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What does 'cog' mean in yacht racing?

Understanding the Basics of Yacht Racing

Before we dive into the specifics of 'cog' in yacht racing, I think it's important to first understand the basics of the sport itself. Yacht racing is a popular water sport that involves sailing yachts and larger sailboats. These races are typically conducted for sport, but they also have a strong cultural significance in some parts of the world. The races can take many forms, but the main goal is always the same: to cross the finish line before your competitors.

Now, when it comes to yacht racing, there are many terms and phrases that can seem confusing to the uninitiated. One such term is 'cog'. This is a term that has a specific meaning in the context of yacht racing, and understanding it can greatly enhance your appreciation of the sport. So, let's delve into the world of yacht racing and unravel the mystery of the cog.

The Definition of 'Cog' in Yacht Racing

In the world of yacht racing, 'cog' is an abbreviation for 'course over ground'. This refers to the actual path that a yacht has taken or is currently taking over the surface of the Earth. The cog is determined by the compass direction in which the vessel is moving. It's important to note that the cog can be different from the heading of the vessel, which is the direction in which the vessel is pointed.

Understanding the cog is crucial for navigators during a yacht race. It helps them to ascertain how their yacht is being affected by the wind, currents and tides. By monitoring the cog, navigators can make necessary adjustments to their course to ensure they reach their destination as quickly as possible.

The Importance of 'Cog' in Yacht Racing

The importance of understanding and monitoring the cog in yacht racing cannot be overstated. It is a critical piece of information that can make the difference between winning and losing a race. For instance, if a yacht is being pushed off course by a strong current, the navigator can use the cog to identify this and adjust their course accordingly.

Moreover, the cog can also be used to predict future course changes. By comparing the current cog with the projected course, navigators can anticipate necessary adjustments and plan their strategy accordingly. This proactive approach can give a team the upper hand in a race.

How to Determine 'Cog' in Yacht Racing

Determining the cog in yacht racing involves the use of sophisticated navigation equipment. Modern yachts are equipped with GPS (Global Positioning System) devices that provide real-time information on the yacht's cog. These devices calculate the cog by comparing the yacht's current position with its position at a previous point in time.

In addition to GPS, navigators also use a compass to verify the cog. By comparing the compass heading with the GPS cog, they can ascertain if the yacht is drifting off course due to wind or current. This double-checking method ensures accurate navigation and optimal performance during the race.

'Cog' vs 'Heading' in Yacht Racing

While the terms 'cog' and 'heading' are often used interchangeably, they have distinct meanings in yacht racing. As we've already discussed, the cog is the actual course that the yacht is following over the ground. On the other hand, the heading is the direction in which the boat is pointed.

The heading can be different from the cog due to wind and current. For instance, if a yacht is sailing into a strong current, the navigator may need to point the yacht at a different angle (the heading) to ensure that the yacht stays on its intended course (the cog). Understanding the difference between these two terms and knowing how to adjust each is key to successful yacht racing.

Written by Maverick Nautica, 17 Jul 2023
Sailing and Yacht Racing
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What is the meaning of ‘cog’ in yacht racing?

In the world of yacht racing, the term “cog” refers to a boat’s ability to sail at a certain angle to the wind. The concept of cog is essential to understanding racing strategy and determining the most efficient course to sail.

Simply put, cog is the angle at which a boat is able to sail as close to the wind as possible while maintaining its speed. It is expressed as an angle in degrees, measured from the true wind direction. For example, a boat sailing at a 45-degree cog is sailing at an angle of 45 degrees from the true wind direction.

In yacht racing, understanding cog is critical for developing a winning strategy. The goal is to sail as close to the wind as possible without sacrificing speed. To do this, sailors must constantly adjust their sails, boat speed, and course to maintain the most efficient cog possible.

Another important factor in determining cog is a boat’s sail plan. Different types of sails, such as genoas and spinnakers, can affect a boat’s cog and overall performance. Sailors must carefully consider their sail plan and make adjustments as necessary to maintain their desired cog.

One of the most significant challenges in yacht racing is dealing with wind shifts. As the wind direction changes, a boat’s cog will change as well. Skilled sailors must be able to read the wind and adjust their course and sail plan accordingly to maintain their desired cog.

In summary, cog is a critical concept in yacht racing that refers to a boat’s ability to sail at a certain angle to the wind. Understanding cog is essential for developing a winning strategy, and skilled sailors must be able to adjust their course and sail plan to maintain their desired cog.

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How To Calculate Course Over Ground (Illustrated Guide)

With a modern GPS and chart plotter, reading a Course Over Ground (COG) number tells you what the COG is. As the name suggests, it's the direction the boat is traveling over the bottom, including any side slipping, current and drifting. It can differ from your compass heading, and it's important to know why.

How do you calculate course over ground? If you have an estimated course and you're doing dead reckoning, you add the known effects of currents to your projected course to derive the COG. With a known start and ending position, COG is measured from a chart.

At its simplest level, imagine your sailboat dragged a chain on the bottom as you sailed, leaving a line through the mud and sand. It doesn't matter what your compass heading was or your angle of sail off the wind, your "Course Over Ground" is literally that line you drew on the bottom. It is the path the boat travels relative to the bottom , no matter which way you're sailing.

COG is not Heading . The heading is the compass direction your boat is pointing, and it may not match COG if you have current and tidal effects. Heading is instantaneous, we derive COG from your boat's motion over time.

If you know where you are now, and you know where you were five minutes ago, describing your COG is just a straight line back to where you were. Your GPS can calculate this because it knows where you were five seconds or five minutes ago, and it displays the number on the fly from the known start and ends.

Calculating COG between two fixed points is easy, it's just plotting points and measuring. On a chart, its primary use is to document what happened since you already have a fix, so you which way you traveled despite the direction the boat was pointed.

Figuring COG when you're doing dead reckoning plots is different - it gives you an estimate of your position and is useful for navigation without a GPS.

If you're not comfortable plotting a point on a chart and measuring a line, start with this guide to be sure you understand dead reckoning and how to plot a point and measure a line . Those skills are important to figuring your COG by either method.

To calculate COG from point A to point B with a chart is simple if you understand the basics of plotting and measuring.

Plot Point A and Point B on your chart.
Draw a straight line from A to B.
With a parallel rule, measure the compass angle of the line and record it.
Adjust the number for magnetic variation, adding West variation and subtracting East.

The final number was your COG between the points.

This is where the calculations get useful and much more interesting. When you are navigating with dead reckoning and paper charts, you estimate your position based on information about your course and heading. But a current can move you miles off course, and you'll never feel it. Accounting for it and estimating it is how we calculate our Course Over Ground.

To do this, you will need a dead reckoning plot - this will be a series of estimated fixes and recordings of speed lines. If you are sailing in an area with known current effects, make the COG adjustment after each DR plot.

For this calculation you will need to know an estimate of the strength and direction of currents affecting the boat - sometimes referred to as set (direction) and drift (speed). This will be a speed in knots and a compass heading.

The steps, including the dead reckoning plot:

From your last fix, calculate how much time has lapsed. We will use an hour, because most DR plots are done on the hour.
Get your compass heading for the last hour and boat speed.
Draw a line from the last fix equal to your boat speed for the measured hour on your heading.
Starting at the end of the line you just drift, draw a line representing the set and drift of the current. This will be the length of the drift on the compass direction of the set.
With your straight edge, draw a line from the last fix to the end of the set/drift line.
Measure the angle of this line against the compass rose to get the Course Over Ground. The Speed over Ground is also the length of the line, if the measured time was an hour.

Other Error Factors

The other major error factor which makes your COG and estimated position inaccurate. The first is leeway , or sideslip. Because the wind is blowing from the side of the boat, the boat is pushed sideways. This effect is most pronounced when sailing to windward and reduces as the wind moves aft and disappears running downwind.

The amount of leeway varies with boat speed, wind speed, and sailing conditions. A boat moving slowly has more leeway, and higher wind speed causes more leeway with more sideways force. Rough conditions, especially when a boat is sailing into waves which slap it backwards, can increase leeway.

Unfortunately, you can't plot a course ahead of time to account for leeway, since it varies with the conditions and you won't know them until you set sail. But you can estimate it once you start sailing, though it's better to adjust your last Course to Steer than it is to plot leeway on your chart, especially if it's upwind to your destination.

Without hard data for leeway (which rarely exists), the best you can do is estimate. Five degrees isn't a terrible estimate to start with for many boats going upwind, but as you sail your boat, you can try to figure a better estimate. Once you have a Course to Steer, add the leeway to your heading to sail a few more degrees upwind, then it will be factored into your COG calculation when you plot it.

Since you have a COG function on your GPS, why take the time to learn how to calculate a less precise number on paper? And what can you do with the COG once you have it?

The answer to "why bother" is the same one for why learn Dead Reckoning navigation - if you lose your instruments or there's a problem with the GPS system you still can get to a safe harbor or home. Understanding basic navigation, even if you never use it, will make your electronic navigation more efficient and safe, and give you a good fallback in case you lose power or your instruments.

But what else can you use COG for?

With electronic navigation, I find it useful as my first clue there are currents at play that I don't know about. It happens more than you expect; most coastal waters have some tidal effects and it's not always obvious what they are doing.

In parts of the world where current plays an enormous factor in navigation, are are often published sets of current data. But those often apply to very specific locations like the entrance of a harbor or canal. Their accuracy is a prediction, not a statement of fact, and your COG can be your first clue you're being swept in a different direction than you're pointing the boat.

Check your COG against your heading when you're sailing. In theory, they should be close together. If they aren't, you've got current, leeway, or both. It gives you a chance to adjust your heading to compensate for the current and stay near the course you plotted. With practice, you can learn enough about your boat to estimate current set and drift from checking the COG against your heading.

If you're a hundred miles from land, a mile or two isn't a big deal. But if you're sailing near the Middle Ground Shoals in Vineyard Sound - a notorious area for fast and shifty tides and currents - that side slippage or push from the current can be the difference between smooth sailing in deep water and bumping a sand bar.

When you're navigating with Dead Reckoning, calculating the COG is a critical step to getting a more accurate DR position in areas with a lot of current. No matter the current set, you want your best position possible. If you know about currents in the area you're sailing, you can account for them before you sail with the Course to Steer - refer to our guide on that topic .

G-whizz Elan 340

Elan 340 sail boat, sail racing abbreviations.

This is a list of around 280 abbreviations and acronyms that you may find in sail racing documentation including; Sail Race Results, Notices of Race and Sailing Instructions.

Other Lists:

List of Racing Abbreviations: Code What does it mean # "No Data":- Data is missing (or questionable) from the results system. [x] [x.y] ">(x) (x.y) [x] [x.y] "Discarded":- The race score inside the brackets is not included in series results. Normally the race score is dropped as per Sailing Insructions. e.g. [2] or [2.5] 2H "Two Handed":- Racing in a division limited to only 2 crew members. 2IC "Second In Charge". ">A "Mediated or Arbitrated Protest Result":- Result of protest determined by mediation or arbitration between the parties without going to full protest hearing. ABDn "Race Abandoned":- The race has been abandoned and will not be re-run. ABN "Race Abandoned":- The race has been abandoned and will not be re-run. ABP "Associated British Ports". AHC "Allocated Handicap":- The handicap allocated before the start of the next scored race. AIS "Automated Identification System":- A system that transmits a boat's position to all boats' in VHF range so that those boats are aware of the transmitter's position. AMS "Australian Measurement System":- A handicap based on physical measurements. AP "All Purpose":- Generally in conjunction with a handicap system e.g. ORC AP. AP "Answering Pennant Code Flag":- This signal flag is used to indicate a postponement or delay to (generally) the race start. ARB "Arbitrated Protest Result":- Result of protest determined by arbitration between the parties without going to full protest hearing. AS Yardstick "Australian Sailing Yardstock":- A handicap system to allow for mixed fleet racing especially Small catamarans and Dinghies, also including small keel boats, based on measurments handicapping systems. ASBA "Australian Sports Boat Association". AVE "Average Points Given":- Average points awarded as apposed to actual scored points, e.g. a boat that failed to finish due to them providing assistance to another. May also exist where a boat's division is changed during a series. AVG "Average Points Given":- Average points awarded as apposed to actual scored points, e.g. a boat that failed to finish due to them providing assistance to another. May also exist where a boat's division is changed during a series. AVS "Angle of Vanishing Stability":- The angle from the vertical at which a boat will no longer stay upright but will capsize. B "Bettered":- Tie broken by one boat bettering another. (No I don't understand this either). Maybe the same as Tie (see below). B "Black Flag Disqualification":- RRS 30.4 (Black flag). Disqualification for being On Course Side (OCS) in a race that was started under black flag conditions. BCE "Back Calculated Elapsed Time":- The difference between a boat's actual elapsed time and the theoretical elapsed time needed to achieve the same corrected time as the winning boat. BCH "Back Calculated Handicap":- A calculated handicap that would have resulted in all boats having the same corrected time for the race. BCR "Back Calculated Rating":-The handicap a boat would have needed to achieve the same corrected time as the winning boat. BCT "Base Corrected Time":- The elapsed time used to determine the BCH. BCYS "Back Calculated Yardstick":- The corrected time divided by the standard boat time and multiplied by its own yardstick. As in AS Yardstick for dinghies. BDS "BeiDou":- Globall Navigation Satellite System (GNSS) - China. BFD "Black Flag Disqualification":- RRS 30.4 (Black flag). Disqualification for being On Course Side (OCS) in a race that was started under black flag conditions. BID "Boat Identification":- Used in event entry systems to give a boat a unique identification. BOM "Bureau of Meteorology":- An Australian Government Agency for producing (Amongst other things) weather forecasts. BOW "Bow Number":- A number fixed to the bow of a boat, normally allocated by the Organising Authority (OA) to a boat without a sail number, eg. A charter boat. BSF "Time on Distance":-Handicap process. (e.g. anticipated seconds a boat takes to travel one Nautical Mile). C "Casual Entry":- Boat not entered into the entire series. Possibly does not collect series points or affect other competitors' points. C "Did Not Compete":- Entered for the race but did not show up to the start area. CBCH "Clamped Back Handicap":- Same as BCH but with preset limits on the amount of adjustment from the AHC. CBH "Class based Handicap":- A Handicap developed to allow boats from various classes to compete against other. CHC "Calculated Handicap":-The handicap that will be applicable to the next race. CL "Class":- Class or Division the boat is competing in. COG "Course Over Ground":- The actual direction of a boat relative to the Earth's surface which may be different to its heading. COLREGS "International Regulations for Preventing Collisions at Sea". Cor'd T "Corrected Time":- Elapsed time after application of handicap. CR "Class Rules":- Rules applicable to a specific Class or design, esp. One design. CRF "Classic Rating Formula":- Handicap system for classic yachts. CT "Corrected Time":- Elapsed time after application of handicap. CV "Committee Vessel":- Normally seen at the starboard end of the start line and/or at the port end of the finish line, it may also be any vessel performorming functions related to the ruuning of the race eg. Setting marks. D "Disqualification":- (other than DGM). Not Excludable under rule 90.3. DBP "Duty Boat Points":- Club specific points for a boat that undertakes Club duties in place of racing . DFL "Dead (Expletive deleted) Last":- Self explanatory. Not an official acronym but heard around the bar of Sailing Clubs. DGM "Disqualified":- Disqualified under RRS 69.1. (Gross Misconduct). DH "Double Handed":- Racing in a division limited to only 2 crew members. DidNot "Did Not Receive a logical Score":- Reason for a boat receiving a score greater than the number of finishers e.g. DNF, DSQ, etc. Div "Division":- Description of or the number of the Division the boat is competing in. Div No "Division":- Description of or the number of the Division the boat is competing in. DNC "Did Not Compete":- Entered for the race but did not present to the start area. Alternate - "Did Not Come". DND "Disqualification Not Discarded":- The Disqualification race points score cannot be excluded (dropped) from the series score. DNE "Disqualification Not Excluded":- The Disqualification race points score cannot be excluded (dropped) from the series score. DNF "Did Not Finish":- Not too sure of the difference to Retired (RET) . Could it be that the boat retired due to a conscious decision made by the Skipper as opposed to not finishing due to external factors. Eg mechanical failure. Refer also Time Limit Exceeded (TLE). DNS "Did Not Start":- Was at the starting area but did not start. DOG "Distance Over Ground":- Distance over the ground, measured point to point, in nautical miles. DP "Discretionary Penalty":- A breach of a rule (Generally in the Sailiing Instructions) notated "DP" may attract a penalty at the discretion of the Race Committee. DP "Discretionary Penalty":- A discretionary penalty applied by the Race Committee which could be positive or negative. DPI "Discretionary Penalty":- A discretionary penalty applied by the Race Committee which could be positive or negative. D-PN " Dixie Portsmouth Number":- The handicap value as calculated by the Portsmouth Yardstick (PY) handicapping system As recognised by United States Sailing Association. DQ "Disqualified":- Will mostly be heard being used by Sail GP broadcast commentators. DR "Derived Rating ":- Resultant Handicap as derived from the Portsmouth Yardstick (PY) for classes/designs not covered by the Measured rating (MR). DR "Development Rule":- World Sailing (WS) process to publish a new Racing Rule for "Temporary Testing". DSC "Digital selective calling":- A standard for transmitting digital messages via Marine radio. It is a core part of the Global Maritime Distress Safety System. DSQ "Disqualified":- Reason for the disqualification should be noted somewhere in documentation. DTF "Distance To Finish":- Distance for the subject boat to go to the finish, measured along the shortest possible course. DTG "Distance To Go":- Distance for the subject boat to go to the finish, measured along the shortest possible course. DTL "Distance to Lead(er).":- The difference between the leader's Distance to go (DTG) and the subject boat's DTG. DUT "Duty Crew":- Points awarded to a boat that was unable to compete due to their duty crew responsibilities. E "Event Specific Penalty":- As defined in the event documentation. ECA "Ensign Class Association". ECS "Electronic Chart System":- An electronic charting system. EHC "Event Handicap":- Based on the performance of a particular boat. The initial EHC handicap reflects previous/known performance for the boat or the type of boat. Elapsd "Elapsed time":- Boats time from race start time to the boats finish time. ENP "Event Nominated Penalty":- As defined in the event documentation. EPIRB "Emergency Position Indicating Radio Beacon" ERS "Equipment Rules Of Sailing". ESP "Event Specific Penalty":- As defined in the event documentation. EST "Estimated". ET "Elapsed time":- Boats time from race start time to the boats finish time. ETA "Estimated Time of Arrival". ETO "Elapsed Time Order":- The order of finishing based on elapsed time. ETord "Elapsed Time Order":- The order of finishing based on elapsed time. EXC "Race Results Excluded":- The results of a particular race are exclude for all boats. F "Did Not Finish":- Not too sure of the difference to Retired (RET) . Could it be that the boat retired due to a conscious decision made by the Skipper as opposed to not fiishing due to external factors. Eg mechanical failure. Refer also Time Limit Exceeded (TLE). Fin Tim "Finish Time":- Finish time at time of day. as opposed to elapsed time. Fleet "Fleet":- Subject boat's situation overall (in the Fleet), irrespective of Class/Division. G "Redress Given":- Points awarded to a boat that due to exceptional circumstances achieved a result worse than the points given. E.G. provided assistance to another boat in difficulty. GLONASS "Global Navigation Satellite System":- a Global Navigation System (GNSS) -Russia. GMDSS "Global Maritime Distress and Safety System":- System for Automated Emergency Signal Communication. GNSS "Global Navigation Satellite System":- E.g. GPS, GLONASS. etc. GPH "General Purpose Handicap":- Based on predicted seconds/mile. GPS "Global Positioning System":- A Global Navigation System (GNSS) - USA. GSC "Galileo":- a Global Navigation System (GNSS) - EU. H "Did not sail course":- Boat finished the race but did not sail the correct course. H1 "One Hull":- Foiling catamaran sailing with one hull in and one hull out of the water. Will mostly be heard being used by Sail GP broadcast commentators describing a boat that is not foiling. H2 "Two Hulls":- Foiling catamaran sailing with both hulls in the water. Will mostly be heard being used by Sail GP broadcast commentators describing a boat that is not foiling. HC "Handicap". HC "Wind Handicap":- A system that is a multi-number extension of the Portsmouth Yardstick (PY) system to account for varied boat performance across a range of wind and sea conditions to correct elapsed times. HCAP "Handicap". HF "High Frequency Radio". HPS "Handicap Points Score":- Points awarded based on handicap performance. I "Discretionary Penalty":- A discretionary penalty applied by the Race Committee, could be positive or negative. IDM "Inner Distance Mark":- A Mark associated with the start line, it could be a mark to protect the committee vessel (Sometimes called a Barging Buoy) or (especially) where the start line is defined by transits. It is not part of the start line but must be passed on the specified side. IJ "International Juror". ILCA "International Laser Class Association". ILM "Inner Limit Mark":- A Mark associated with the start line, it could be a mark to protect the committee vessel (Sometimes called a Barging Buoy) or (especially) where the start line is defined by transits. It is not part of the start line but must be passed on the specified side. IMA "International Maxi Association". IMO "International Maritime Organisation". IMOCA "International Monohull Open Class Association". IMS "International Measurement System":- A handicap based on physical measurements. IMSAR "International Aeronautical and Maritime Search and Rescue":- IMSAR Manual is a manual for the operation of Maritime and Aviation Search and Rescue. IOR "International Offshore Rule":- A handicap based on physical measurements. IPH "Initial Provisional handicap". IRC "International Racing Conference":- A handicap based on physical measurements. Adminitered by 'Union Nationale pour la Course au Large' (UNCL) from France and 'Royal Offshore Racing Club' (RORC) from Britaim. IRC TPR "International Racing Conference - TP52 Rating":- Unique to TP52 One design boats, calculate using the boat's IRC handicap and adjusted for boat age, crew age and number and crew professional status. IRNSS "Indian Regional Navigation Satellite System":- a Global Navigation System (GNSS) -India. IRO "International Race Officer". IRPC "Individually Rated Production Class":- In PHRF where a production model boat has been modified or does not otherwise fall within the definition of a standard production model. IRPCAS "International Regulations for Preventing Collisions at Sea". IRPCS "International Regulations for Preventing Collisions at Sea". ISAF "International Sailing Federation":- (Now known as "World Sailing"). ISO "International Organization for Standardization". ISYR "International Superyacht Rule". ITMA "International 12 Meter Association". JAM "Jib and Main Only":- Boats restricted to conventional headsail and main only. Spinnakers not be allowed. KB "Keel Boat". L "Late Entrant":- Boat joined series after first race. LB "Laid Buoy":- A temporary buoy laid by the Race Committee as a mark of the Course. LBCHD "Limited Back Handicap Discard":- Same as BCH but discarded when the variation to AHC is greater than preset limits. LBCHL "Limited Back Handicap Lower":- Same as BCH but with preset limits on the amount of Lower adjustment. LBCHU "Limited Back Handicap Upper":- Same as BCH but with preset limits on the amount of Upper adjustment. LH "Hull Length":- Used in some handicap measurement system documentation. LH "Line Honours". LM "Laid mark":- A mark laid out by (generally) the race committee to act as a mark of the course. LM "Leeward Mark". LOA "Length Overall". LTP "Long Term Performance":- Performance based handicap system for sports boats. LWL "Length at Waterline" M "Disqualified":- Disqualified under RRS 69.1. (Gross Misconduct). M(n) "Mark (Insert number here)":- A mark of the Course. M1 "Mark One":- A mark of the Course. M2 "Mark Two":- A mark of the Course. MCCF "Mixed Class Correction Factor":- applies to fleets containing multihulls and monohulls or sailboards and monohulls. MED "Mediated Protest Result":- Result of protest determined by mediation between the parties without going to full protest hearing. MMSI "Maritime Mobile Service Identity":- Is a unique nine digit number that is entered into certain marine radio communications equipment. MOB "Man Over Board". MOCRA "Multihull Offshore Cruising and Racing Association". MPZ "Moving Prohibited Zone":- A moving zone that entry into is prohibited. E.g the exclusion zone surrounding a moving ship or Passenger Ferry> MR "Measured Rating":- Resultant Handicap as derived from the Portsmouth Yardstick (PY). MSA "Maritime Safety Act". N "Event Specific Penalty":- As defined in the event documentation. NCL "No Crew List ":- This Boat has failed to submit an accurate Crew List . NER "No Entry Received":- Subject boat did not enter for this particular race. NET "Net Series Score":- The sum of all race scores in a series less any scores dropped (scores that are not counted). NHC "National Handicap for Cruisers":- Based on the boat's previous performances. NJ "National Juror". NM (nm) "Nautical mile":- One Nautical mile approximates 1,852 meters. NOC "National Olympic Committee". NOD "No Declaration":- A declaration form has not been submitted within the required time frame. These declarations could include compliance or post race declarations, or declaration(s) as specified in the Sailing Instructions. Generally a penalty will apply. NOR "Notice of Race". NP "Non Point score":- A race that is part of a series but does not contribute to the score of that series. NP "Not Protest":- A boat may not protest another boat that is in breach of a rule (Generally in the Sailing Instructions) that is notated with (NP). NS "Non Spinnaker":- Boats racing in a division where spinnakers are not permitted. NTC "Notice To Competitors". NSC "Did not sail course":- Boat finished the race but did not sail the correct course. O "On Course Side" :- Over the line at the start. Or broke RRS 30.1 (I Flag) Start conditions. Alternate - "On Course at Start". OA "Organising Authority". OCS "On Course Side" :- Over the line at the start. Or broke RRS 30.1 (I Flag) Start conditions. Alternate - "On Course at Start". OD "One Design". A form of racing where all boats are virtually identical or similar in design. Each One Design class will have its own set of specification rules. ODM "Outer Distance Mark":- A Mark associated with the start line, it could be "Pin End" and part of the start line or (especially) where the start line is defined by transits it is not part of the start line but must be passed on the specified side. OffSet "Off Set Time":- The waiting period or offset which is subtracted from the finish time to work out the elapsed time, Generally applicable to pursuit stars. The subject boat's pursuit start handicap sutracted from its finish time equals its actual elapsed time. OLM "Outer Limit Mark":- A Mark associated with the start line, it could be "Pin End" and part of the start line or (especially) where the start line is defined by transits it is not part of the start line but must be passed on the specified side. OMR "Offshore Multihull Rating". "Offshore Multihull Rule":- A measurement based handicap system for multihulls. Same Acronym interpreted differently by various organisations. ONB "Official Notice Board". OOD "Officer Of the Day". ORA "Officer Of the Day".Offshore Racing Association". ORC "Off Shore Racing Conference". ORC AP "Off Shore Racing Conference - All Purpose":- A measurement based handicap rating system. For handicapping boats in all except Winward Leeward races. ORC DH "Off Shore Racing Conference - Double Handed":- A measurement based handicap rating system. For handicapping boats competing in Double Handed divisions. ORC WL "Off Shore Racing Conference - Windward Leeward":- A measurement based handicap rating system. For handicapping boats in Windward Leeward races. ORCc "Off Shore Racing Conference - Club":- A measurement based handicap rating system. Based on honesty self measurement. ORCi "Off Shore Racing Conference - International":- A measurement based handicap rating system. ORR "Off Shore Racing Rule":- A measurement based handicap rating system. ORR EZ "Off Shore Racing Rule":- A measurement based handicap rating system with algorithms to recognise performance differences in points of sail, e.g. Reaching Vs running, running vs beating etc. OSR "Offshore Special Regulation(s)". OTB "Off The Beach":- Normally associated with dinghy classes where the boats are launched off the beach". OTL "Ouside Time Limit":- Finished outside of the time limit applicable to that race. OV "Overall":- Subject boat's situation overall, irrespective of Class/Division. OWC "Off Wind Course":-Part of the PHRF rating system, is used when the anticipated course majority off wind. P "Port":- Normally associated with a course mark - leave to port. P "Protest pending". PBH "Performance Based Handicap":- Based on the boat's previous performances. PBO "Poor Bloody Owner". Normally relate to the weight (or lack thereof) of the owners wallet. PCS "Polar Curve Scoring":- Yachts of different designs have different time allowances depending on weather conditions and course configuration. PD "Percentage Difference":- The percentage difference between AHC and BCH. PF "Performance Factor":- The BCYS divided by the boat's class yardstick. As in AS Yardstick for dinghies. PFD "Personal Flotation Device":- Life Jacket. PHRF "Performance Handicap Racing Fleet":- Handicap system based on the previous performances of all boats of a particular class, design or Model. PHRF-xx "Performance Handicap Racing Fleet" "xx":- xx = the abbreviation of the local PHRF jurisdiction. E.g. LO = Lake Ontario, NB = Narragansett Bay, NE = New England. USA location list here ussailing.org/competition/offshore/phrf/phrf-fleet-contact-directory PHS "Performance Handicap System":- Based on the boat's previous performances relative to the performance of other boats. PiC "Person in Charge" PLB "Personal Locator Beacon". PMR "Pacific Multihull Rating"- Resultant Multihull Handicap as derived from the Portsmouth Yardstick (PY). PN "Portsmouth Number":- The handicap value as calculated by the Portsmouth Yardstick handicapping system (PY). POB "People On Board". Alternate - "Persons On Board". Alternate - "Pax On Board". Alternate - "Personnes Ã Bord". Alternate - "Persone a bordo". (Take your pick - Sorry got carried away). PP "Protest Panel". PRO "Principal Race Officer". PTL "Protest Time Limit":- The time window available for lodging of a protest. PY "Portsmouth Yardstick":- A empirical handicap system first developed in (believe it or not) Portsmouth. Q "Disqualified":- Reason for the disqualification should be noted somewhere in documentation. QZNS "Quasi-Zenith Satellite System":- A Global Navigation System (GNSS) -Japan. R "Race". R "Retired":- Not too sure of the difference to DNF however in Motor racing a competitor is scored RET while the race is still in progress and DNF after the event is finished. R "Race Number":- Indicates the race number in which this boat broke a series score tie. e.g. R3 RAF "Retired After Finishing". RC "Race Committee". RCB "Race Committee Boat". RCD "Recreactional Craft Directive":- Boats covered by the Directive are required to comply with specific ISO standards. RD "Race Director". RDG "Redress Given":- Points awarded to a boat that due to exceptional circumstances achieved a result worse than the points given. E.G. provided assistance to another boat in difficulty. RET "Retired":- Not too sure of the difference to Did Not Finish (DNF) . Could it be that the boat retired due to a conscious decision made by the Skipper as opposed to not finishing due to external factors. Eg mechanical failure. Refer also Time Limit Exceeded (TLE). RIB "Rigid Inflatable Boat". RLC "Random Leg Course":-Part of the PHRF rating system, is used when the anticipated course is neither windward/Leeward or majority off wind. Rn "Race Number":- Indicates the race number in which this boat broke a series score tie. e.g. R3 RO "Race Officer". RORC "Royal Offshore Racing Club":- A British Club that manages IRC from Britain, see also UNCL. RR "Racing Rule". RRS "Racing Rules of Sailing":- Or to those that like to remember before electronic publishing; The Blue Book (In Australia). RTD "Retired":- Not too sure of the difference to Did Not Finish (DNF) . Could it be that the boat retired due to a conscious decision made by the Skipper as opposed to not finishing due to external factors. Eg mechanical failure. Refer also Time Limit Exceeded (TLE). RYA Yardstick "Royal Yachting Association Yardstock":- A handicap system to allow formixed fleet racing especially Small catamarans and Dinghies, also including small keel boats, based on measurments handicapping systems. S "Did not start":- Was at the starting area but did not start. S "Score":- Indicates the score value that this boat received as a tie breaker. Boats with equal series scores but whose hierarchy is determined by a count back system indicated in SIs. E.g the boat with the most 1st paces etc. May also be used to indicate the individual race score that determined the result of the count back. e.g. 1S 1.5S S "Starboard":- Normally associated with a course mark - leave to starboard, SAR "Search and Rescue". SBT "Standard Boat Time":- The corrected time for the first boat on corrected times to sail a proper course. Alternatively, a consistently sailed boat finishing in the top five of the fleet, on corrected time, can be taken as the standard boat . As in AS Yardstick for dinghies. SC "Scoring Penalty Applied":- Penalty applied, generally withaut an a hearing e.g. entering the restricted start entry before a boat's appropriate tine. SCD "Safety Compliance Declaration". SCHRS "Small Catamaran Handicap Rating System":- A handicap based on physical measurements for small catamarans. SCP "Scoring Penalty Applied":- Penalty applied, generally withaut an a hearing e.g. entering the restricted start entry before a boat's appropriate tine. SCP "Scoring Penalty Taken":- Rule 44.3. SER "Safety Equipment Requirements". SER "Single Event Rating". Sers "Series". SI "Sailing Instructions". SIN "Sailing Australia Number". SIs "Sailing Instructions". SKED "Schedule":- E.g time(s) of scheduled reporting of position. SML "Stone Motherless Last":- Not an official acronym but often heard around the bar at Sailing Clubs. Maybe a declaration that victory has many parents but defeat has none. SMS "Short Message System":- Better known as a text on on a mobile (cell) phone. SMS "Sport Boat Measurement System". A handicap based on physical measurements. SOG "Speed Over the Ground":- The speed the boat is moving relative to the surface of the earth. SOLAS "International Convention for the Safety of Life at Sea":- A International maritime treaty that sets minimum safety standard. SOP "Sign On/Sign Off Penalty":-This Boat did not Sign On/Sign Off . SORC "Southern Ocean Racing Conference". SP "Scoring Penalty":- A Breach of a rule notated "SP" may attract a penalty without a hearing. SP "Standard Penalty". SPIN "Spinnaker":- Spinnakers allowed. As apposed to Jib and Main Only (JAM). SR "Special Regulations":- The regulations dictating the equipment required on a boat to be legal to race, generally published with the RRS. SSS "Safety and Stability Screening":- A base value for the boat is calculated from the boat's dimensions and rated parameters. STCW "Standards of Training, Certification, and Watchkeeping":- A comprehensive set of international regulations that determine the qualifications and certifications required of seafarers. STIX "Stability Index". STP "Standard Penalty":- Penalty applied (normally not an on-water incident) due to an infringement that was specified the NoR or SIS, could include not reporting to officers pre/post race or not returning equipment e.g. a tracker. STW "Through The Water". T "Tie broken":- Tie broken by one boat having more of a particular score. E.g firsts. T "Time Limit Exceeded":- Finished outside of the time limit applicable to that race. TCC "Time on Time Handicap". TCF "Time Correction Factor":- Handicap value to determine corrected time. TD "Time Difference":- difference in time between fastest corrected time and subject boat's corrected time. TES "TopYacht Entry System":- Entry system that is part of the TopYacht race scoring system. TES-BID "TopYacht Entry System - Boat Id". TH "Two Handed":- Racing in a division limited to only 2 crew members. Tie(s) "Scoring Tie(s)":- Indicates boats with equal series scores but whose hierarchy is determined by a count back system indicated in SIs. E.g the boat with the most 1st paces etc. May also be used to indicate the individual race score that determined the result of the count back. TLE "Time Limit Exceeded":- Finished outside of the time limit applicable to that race. TLP "Time Limit Penalty":- Penalty applied to boats that failed to finish within a specified tile after the first boat to finish. TOD "Time on Distance":-Handicap process. (e.g. anticipated seconds a boat takes to travel one Nautical Mile). TOT "Time on Time Handicap". TPR "TP52 Rating":- Unique to TP52 One design boats, calculate using the boat's IRC handicap and adjusted for boat age, crew age and number and crew professional status. TS "Traffic Separation". TSS "Traffic Separation Scheme". U "U Flag Disqualification":- RRS 30.3 (U flag). Disqualification for being On Course Side (OCS) in a race that was started under"U" flag conditions. UFD "U Flag Disqualification":- RRS 30.3 (U flag). Disqualification for being On Course Side (OCS) in a race that was started under"U" flag conditions. UNCL "Union Nationale pour la Course au Large":- A French Club that manages IRC from France, see also RORC. US Yardstick "United States Sailing Yardstock":- A handicap system to allow formixed fleet racing especially Small catamarans and Dinghies, also including small keel boats, based on measurments handicapping systems. USSA PN "United States Sailing Association Portsmith Number":- A handicap system to allow formixed fleet racing especially Small catamarans and Dinghies, also including small keel boats, based on measurments handicapping systems. USSER "US Safety Equipment Regulations". UTC "Universal Time Coordinated":- UTC (A time Standard) is the time at the time zone known as Greenwich Mean Time. V "Average Points Given":- Average points awarded as apposed to actual scored points, e.g. a boat that failed to finish due to them providing assistance to another. May also exist where a boat's division is changed during a series. VHF "Very High Frequency Radio":- Often expressed as VHF channel 77, VHF Ch 77 or VHF 77. Vis "Visitor":- Possibly does not collect series points or affect other competitors' points. VMC "Velocity Made on Course":- Speed of a boat projected on the theoretical route. VPP "Velocity Prediction Program":- Used in ORC and others to predict a yacht's performance. Vs "Visitor":- Possibly does not collect series points or affect other competitors' points. VTS "Vessel Traffic Service". W "Duty Crew":- Points awarded to a boat that was unable to compete due to their duty crew responsibilities. W/L "Windward/Leeward". WL "Windward/Leeward". WM "Windward Mark". WRS "Weather Routing Scoring": A factor that alters a boats handicap based on the forecast weather conditions and the boats forecast performance in those weather conditions. X "Race Results Excluded":- The results of a particular race are excluded for all boats. XWL "Wrong Finish Line":- Subject boat finished on the wrong finsh line. Y "Scoring Penalty Taken":- Rule 44.3. YB "YB Tracker":- A propriety global tracking system. Originally known as "Yellow Brick". YOB "Year Of Birth". YTC "Yacht Time Correction":- A simple measurement based handicap system. Z "Z Flag Penalty":- RRS 30.2 (Z flag). 20% PENALTY for being On Course Side (OCS) in a race that was started under Z code flag conditions. ZFP "Z Flag Penalty":- RRS 30.2 (Z flag). 20% PENALTY for being On Course Side (OCS) in a race that was started under Z code flag conditions.

This list came about from those occasions when we looked at the results of a yacht race or a regatta and have seen an abbreviation or an acronym and wondered what those Sail Racing Abbreviations meant, we would google “what does ??? mean in sailing”, the results of which were sometimes a bit obscure others easier, a list started from there, we hope it is of some value to you.

Many of these Racing Abbreviations are self explanatory, however on some occasions they can be somewhat (actually quite) obscure, leading us to wonder just what does ??? mean in sailing, It almost appears that at times the PRO (Look it up) puts in abbreviations or anagrams in an attempt to show their audience that they know more about the subject than the reader. At other times and quite sensibly these abbreviations and anagrams are just a way of saving space in a results table and/or publication time.

This list may be a little “AussieCentric” as that is where we live and take most interest in race results, also one of the resources used was the Top Yacht Scoring system that is popular with clubs in Australia. There are a few different acronyms and abbreviations in sailing that appear to have the same meaning, there are also a few sail racing abbreviations and sail racing acronyms that have differing meanings, this is probably due to differing scoring regimes in different jurisdictions, they may have subtly different meanings.

Please feel free to contact us with any comments or suggestions regarding this list.

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What are My Electronics Telling Me About Boatspeed and Heading?

By Miles Seddon
Updated: May 21, 2015

With the increasing accuracy and update speeds of modern GPS units, it’s common for sailors to wonder whether using Speed Over Ground and Course Over Ground would be better than the old technology of paddlewheels and magnetic compass. In other words, is it time for us to throw away the paddlewheel and compass?

To begin with, let’s take a look at where SOG and COG come from, and if we can rely on them. SOG and COG are output from your GPS receiver. There are two methods the receiver can use to derive SOG and COG. The first and most basic is to measure the change in position from the previous fix to the present fix and calculate the speed and direction based on the time between fixes. The second, more complex and more accurate way, is to measure the Doppler shift between the received signal and the primary carrier frequency from the satellite.

Since the U.S. Government turned off Selective Availability in 2000 and WAAS was introduced in 2003, we have seen better position fixing accuracy and as a result more people using and relying on GPS. This has lead to some rapid technology advances and reduction of costs.

Until recently, most GPS receivers transmitted position, SOG, and COG data once per second, making it slow for the purposes of yacht racing. In the past five years, we have seen an increase in the number of GPS receivers on the market that output position, COG, and SOG at five times per second (5Hz). This is much more suitable for racing, especially in a starting sequence when the yacht is maneuvering a lot. Today, top-of-the-range GPS receivers, typically used for precision survey work, output data at up to 20Hz.

As this technology becomes more affordable, we will see it filter down from the America’s Cup and Volvo Ocean Race to become common on every boat. So technologically, with a fast updating GPS antenna and more accurate GPS position fixing, there’s little reason not to trust the accuracy of the SOG and COG data, but as a racing navigator we should question whether this is the correct data to be feeding into our instrument system and what impact it will have on other numbers down the line.

As their names suggest, speed over ground and course over ground are measurements related to solid ground. This means that using SOG and COG as accurate sources of speed and heading is fine if we are in a car, as we are in direct contact with the ground, but in a sailboat we have water moving independently between us and the sea bed. Even on a large freshwater lake, the water often moves compared to the ground.

If we want to be able to quantify the performance of our boat, we need to be able to measure our speed and heading through the water. This is best done with a sensor that measures water flow across the hull of the boat, such as a paddlewheel or ultrasonic speed sensor, and a sensor that measures the direction the bow of the boat is pointing in such as a magnetic compass, GPS compass, or, if the budget extends to it, a gyro compass.

If we rely on SOG as a measurement of boatspeed and we are sailing in waters with any current, we will struggle to reach our targets. With foul current, we will never reach our target boatspeed, and with favorable current we will out perform our targets, leading our crew to have little faith in the polars, the instruments, or worse still, the navigator.

Most importantly, our instrument system won’t be able to calculate accurate sailing wind. Diagram 1 shows a simplified view of how we use boatspeed to calculate True Wind Speed (TWS) and True Wind Angle (TWA), and how we can use heading to calculate the True Wind Direction (TWD).

In Diagram 2, we can see what happens if we substitute boatspeed with SOG and we are sailing in an area with current. In this instance, the favorable current is giving us a faster SOG than speed through the water, but this is reducing our TWS and shifting our TWD. In fact, we are no longer calculating our True Wind Speed, but instead our Ground Wind Speed. The same is true if we substitute heading with COG, we are no longer able to derive the TWD, but instead we can calculate the Ground Wind Direction.

Ground wind has an important use on a sailing boat, it’s the wind that blows across the land and is what’s given in your weather forecast, but it’s not the wind that we are sailing in, so tactically—and navigational—it’s of little use outside of Optimum Routing calculations.

So if we cannot use SOG and COG for boatspeed and heading what can we use them for? If we combine an accurate speed through the water and heading with SOG and COG, we are able to derive the actual effects of the current on our boat. Some instrument systems will take this data and calculate the tide set and tide rate for us, which can have tremendous tactical advantages when racing in areas with significant tidal currents, such as San Francisco.

If you’re fortunate enough to be sailing on a boat where the difference between the boatspeed and the tide rate is very large (such as a large multihull traveling at 30 knots in a 1-knot current) then it would be safe to use SOG as a replacement for boatspeed without many issues. In fact, at these high speeds, SOG is often much more accurate than a paddlewheel sensor, so it has become common practice on large multihulls to use SOG from top of the range GPS receivers as a replacement for speed through the water, especially at higher speeds.

When we are out racing around buoys, or want to be sure we can lay a headland, COG is the essential piece of information to determine whether we’re making that mark or not. It’s good practice as a navigator to note your COG on each tack while sailing to a mark or, if you are using tactical software, to run a strip chart of COG for the past 15 minutes. As an example, if we are sailing up to the starboard layline on port tack, we should know what our last starboard tack average COG was, either from our “wet notes” or a strip chart. Provided the wind has not shifted, or the current changed, this will be the number that we want to see through the hand bearing compass when we tack, though there is still a large element of good luck involved in any layline call.

Boatspeed to Calculate True Wind Speed

Using Speed Over Ground

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Racing Signals: Sailing Flag Meanings

Last Updated by

Gabriel Hannon

August 30, 2022

Where other competitions have umpires and referees right next to the players, sailing race committees have to rely on flags to communicate with sailors.

In this article, we are going to explain the meanings of all the flags used at regattas to communicate with sailors. The flags can give information about starting procedures, course information, and on-the-water judging, so a basic understanding is a crucial part of general seamanship.

While nautical flags all have defined meanings in a historical context, they have very specific meanings in the context of racing competition. For instance, in the general nautical world, the Z-flag means that you are in distress and are in need of a tow or relief from a tug boat. At a regatta, the race committee may fly the Z-flag to indicate an additional penalty for any boat that has crossed the line early. Moreover, even though there are certain flags that have well-defined roles, race committees may stipulate additional meanings or introduce new flags via an announcement in the sailing instructions for the event, so we will cover some of these more common changes as well. We will break down the meanings into the various categories of usage.

A secret that I have learned over many years of regattas at every level from proverbial ‘beer-can’ races to national championships is that, as well as both you and the race committee can recite the racing flag rules on land, someone is always going to make a mistake or misunderstand these symbols. That is why I will be going through the official flag meanings and rules from the Racing Rules of Sailing for 2021-2024 to clarify any questions that you might have when the race committee flies a flag that hasn’t been seen since we used Clipper Ships to cross the oceans. Hopefully this article will help break down all the most common signals so that when your friend turns to you and asks ‘is that the flag that tells us it's time to go in,’ you’ll be able to help out!

Table of contents

‍ Flags at the Start

The start of a race is often the most confusing part of a regatta and is where the most flags must be used. We will be going over the rules for the flags at a basic 5-minute start. These can be modified for 3-minute dinghy starts, 5-minute match race starts, 6-minute Olympic starts, or 10-minute big boat starts, but the same logic applies.

A few flags are crucial to set everything up on the starting line prior to the starting sequence.

To begin, the race committee must have an Orange Flag visibly displayed, as this demarks the exact location on the boat from which the line is called. If there is a pin boat, they will often fly an Orange Flag as well, but if it is just a buoy, then the buoy serves as the other end of the line.

Next, the RC will additionally fly the L Flag if they are ready for competitors to check-in at the beginning of the race day. This helps them confirm that everyone is sailing under the correct sail number, which is often a logistical nightmare. They will blow one horn when raising this flag. If this flag is raised at any point later in the day, it is meant to tell competitors to come by the committee boat again.

Finally, the AP Flag is a general purpose postponement flag. The race committee may raise this on land to indicate that the harbor start has been delayed or on the water to indicate that there will be a delay in the starts. While there are other flags that are used for abandonment situations, particularly the N Flag, the AP is commonly used in informal situations. Two sounds accompany the raising of the AP, and it can be said that competitors are ‘under AP’ until it is dropped, along with one sound. If it is dropped on land, competitors may immediately launch. If it is dropped on the water, the next start may begin in as little as one minute.

The final note with the AP Flag is that the race committee may indicate the end of racing for the day by flying ‘AP over A.’ Again, the AP could technically be replaced with the blue and white checkerboarded N Flag, but the two serve very similar purposes at most levels.

Starting Flags

Once the race committee is set up and everyone is ready to go sailing, the next task is to get the right fleets to the starting line for their start. At the warning signal, one loud horn that indicates that the 5-minute countdown to the start has begun, the race committee will raise some type of Class Flag that indicates which type of boat will be starting. Above we have the different class flags for the different competition rigs for the ILCA-Dinghy, formerly known as the Laser, which would be raised to indicate which rig is starting.

This is a convention even if there is only one class on the water. Sometimes this is replaced with raising the Orange Flag itself, or some other flag as laid out in the sailing instructions. Often classes have been assigned a numeral pennant, of which 1-4 are displayed above, in place of the highly specific Class Flags. Still, some flag of this nature goes up at 5-minutes and remains up until go, at which point it is dropped.

At 4-minutes, the RC will sound another horn, known as the preparatory signal, and raise some combination of the above flags.

The P Flag is always required to go up, and it is simply the ‘Prep Flag,’ which signals to the racers that they need to get serious about the race. Once the P Flag is raised, all the right-of-way rules that apply during the start switch on and racers, particularly in team and match racing, are allowed to begin tactically engaging with each other (though in team racing this would happen at minute 2 of the 3-minute start). Moreover, racers can talk with their coaches until the prep signal, and race committees may alter the course up until this moment. Afterwards, all coaching is banned and all course changes on the current leg are not allowed. This belies the fact that a 5-minute starting sequence is actually a 4-minute sequence with a warning signal at 5-minutes, but that is a purely semantic detail.

Depending on how rowdy the competitors are, the race committee may raise any combination of the I, Z, U, or Black Flags. Each of these flags deals with boats that start ‘on-course side’ (OCS), essentially a false start for sailing. If any of these flags is raised, a boat is not allowed to be anywhere within the triangle formed by the starting line and the first mark of the course after the 1-minute signal during the start. These flags essentially help the RC ensure that they can get off a clean start and ensure that they can identify any boats that are OCS at go. When they are flown, the following penalties are added beyond requiring a boat to clear itself by dipping back under the line:

I Flag: Conventionally referred to as the ‘one-minute rule,’ this requires that any boat over the line after a minute also has to sail around an end of the line in order to start the race fairly. This punishes a boat for being over by potentially making it a little harder to clear themselves if they are over on a large line.
Z Flag: Often flown in combination with the I Flag, this flag adds that any boat that is OCS will get a 20% penalty on top of their score in that race, regardless of whether they clear themselves or not. This further hurts any boat that is ‘pushing the line’ by ensuring that even if they manage to clear themselves and come back, they will still see an impact on their scoreline that is equivalent to immediately being passed by 20% of the fleet.
U Flag: Now we’re getting into harsh territory. When the RC is really trying to brush the fleet back off the plate, this flag immediately disqualifies a boat that is over after a minute with no course for redress. If these boats are identified, they tend to be told to stop sailing the race by a notice board at the top mark.
Black Flag: The black flag serves a very similar purpose to the U Flag, except it is a step harsher. It disqualifies you after a minute and even prevents you from sailing in a restart of the race or a race abandoned halfway through.

The I Flag is by far the most common flag, and is often effective at keeping boats from being over. The U Flag rule was introduced in 2013 as an option and formally codified in the Racing Rules in 2017 and is massively more popular than the Black Flag, which is considered overly punitive. In particular, when many sailors are over in a Black Flag start, such that the RC cannot determine who was over, they are forced to make unfair decisions that carry over to the restart, so the U is now almost universally used in its place. Additionally, as the U has become more popular, people tend to shy away from the Z flag, which is considered cumbersome for scorers and confusing to sailors.

In general, while these flags are supposed to be raised in conjunction with the P Flag, often the RC will only raise the most punitive of the flags, as any of them can essentially be considered as a prep flag.

As the starting sequence continues, any prep flag(s) raised must be lowered at the 1-minute signal. The class flag is then lowered at go, leading to the next category of flags: Recall Flags

Recall Flags

After the pain of raising and lowering all those start flags, the RC then has three possible jobs. If the start is clean, they shout ‘All Clear!’ and can then relax until they have to start another race or record finishes for the race in progress. Unfortunately, this is often not the case, as they likely will need to ‘recall’ certain competitors for being ‘OCS,’ i.e. false starting. They have two choices here.

If only a few, easily-identifiable boats have started early, the RC will raise the X Flag along with a single sound in what is referred to as an individual recall. This indicates to the boats on the course that there are some competitors who are currently OCS and must clear themselves. If the I Flag had been flown for the start, competitors have to round an end; if not, they can just dip back behind the starting line and restart from there.

While the X is suitable on its own to inform a boat that it has been called over, it is an oft practiced courtesy for the RC to hail an OCS boat’s sail number over a megaphone, a radio, or other transmission device. The X Flag is dropped when all OCS boats have cleared themselves or after 4 minutes from go, whichever comes first.

If more boats than can be easily identified are called over, the RC can blow two horns and fly the First Substitute Flag, indicating a general recall. In this case, the race is fully reset and the committee will initiate another entire starting sequence for that fleet. After a general recall, the RC will often, but not always employ the next level of penalty flag for the restart in an attempt to get the race off cleanly.

Sometimes, as in college sailing or as stipulated by other sailing instructions, any general recall immediately implies the I Flag for the next sequence if it had not been flown previously. As such, the RC does not necessarily have to fly the I if it is unavailable. Still, such stipulations are almost always written out explicitly for a given event and are often accompanied by a verbal announcement as a courtesy.

Still, outside some usages of the AP or N Flags to abandon or delay starts already in sequence, these are all the flags that deal with general housekeeping and the starting sequence.

While Underway

While the starting flags are by far the most complicated of the flag rules, there are still other flags to keep track of while racing. The first among these are...

Course Change Flags

Although course changes are relatively rare, race committees often pull them out when conditions change substantially during races or if there has been a problem with one of the marks.

When wind or time constraints require, the race committee may send an official to any mark of the course that no boat has yet rounded and have it raise the S Flag along with two sounds. This indicates that the fleet shall finish at that mark, cutting off the race earlier than written in the sailing instructions.

In the case of any other change to the course, such as a minor adjustment to the angle or distance of an upcoming leg, a race committee boat will go to the preceding mark and raise the C Flag along with repeated sounds.

This is sometimes accompanied by a Red Square or a Green Triangle to indicate that the mark has been moved to port or starboard respectively. Although during less formal events, you can change the positions of any marks so long as there are no competitors currently sailing on that leg of the course, it is considered poor form if at all possible to inform competitors, particularly in longer races. Sailors make decisions based on the position of the marks, and if this has been changed without them noticing, that can drastically affect the outcomes of strategic decisions, so in large competitions the C Flag is a must.

If, meanwhile, something odd has happened to a mark of the course, any official boat may fly the M Flag with repeated signals. This serves to inform the competitors that they have become a replacement for the missing mark. This is relatively uncommon, but anchors do occasionally snap on marks, so it is always good to have a support boat with the M if possible.

Finally, as mentioned before, if conditions have deteriorated to the point that a race is considered no longer possible, due to lack of wind, fear of foul weather, or some form of interference -- I’ve seen it happen because cruise ships wanted to pass through a dinghy course, and you don’t say no to them -- the race committee may abandon the race using the N Flag. Still, this flag is relatively rare as you will often see the AP in its place for convenience, as they are functionally similar.

Miscellaneous Flags

While we have covered the bulk of the flags necessary for racing at any level, there are a few more flags from across different disciplines and classes that are worth mentioning, if only to let you in on these quirky parts of the racing world! This starts with what one could reasonably call…

The Cheating Flag

Calling the O Flag the cheating flag is certainly a bit of a misnomer. The O Flag does, however, suspend Rule 42 of the Racing Rules of Sailing. Rule 42 is particularly notorious, as it bans pumping, rocking, ooching, sculling, and excessive maneuvering, all of which are methods to make your boat go substantially faster. While Rule 42 is worth an article in and of itself, the larger point is that it is meant to keep anyone from gaining an unfair advantage over their competitors.

Certain competitive classes, however, including the Olympic class 470s and Finns and many of the new foiling fleets, allow competitors to ignore Rule 42 in certain conditions, typically in heavy breezes that are referred to as ‘planing’ conditions. There are differences across the classes, but whenever it is allowed and the RC flies the O Flag, Rule 42 is switched off and competitors can ooch, pump, rock, and tack their boats all around the racecourse. This allows for a much more physical style of sailing and is a rule that many different classes and sectors of sailing are beginning to consider.

If conditions no longer meet the threshold for that class’s rules regarding suspension of Rule 42, an official boat will raise the R Flag at some point during the race. They can only do so at a mark of the course so that it is fair to all the competitors throughout the fleet. This is relatively rare, and is normally done between races, but is still a key part of the O Flag rule.

Judge and Umpire Flags

On the topic of Rule 42, there are certain fouls in sailing that can be actively enforced on the water by judges or umpires, depending on the context.

Rule 42 is enforced by judges with a Yellow Flag, which they will point at an offending boat along with a sound signal and a direct sail number hail. That boat may clear themselves from their first Yellow Flag by taking their two-turn penalty, but, unless otherwise noted in the sailing instructions, any subsequent violation can entail disqualification.

Finally, certain levels of modern match and team racing, with the addition of high-performance racing like SailGP, have full on-the-water umpires who actively follow the racing to make calls on fouls and other plays. While this is not the spot to go through the intricacies of team and match race calls, the basic gist is as follows.

In any interaction, any boat involved in the race may call in the umpires if they believe that their opponent has fouled them. If the opponent clears themselves quickly, essentially admitting fault, the umpires will not get involved. If no boats clear themselves, the umpire has to make a call on whether there has been a foul. If they determine that the maneuvers were clean, they will make one sound and fly a Green Flag, thus exonerating all boats in the interaction. If they determine there was a foul, they will fly a Red Flag with a singular sound and hail the offending boat.

Beyond that, if a boat is found to have broken a rule not related to an interaction, the umpires may come in and fly the Red Flag without being directly invited into the situation. Further, if a boat is found to be in violation of sportsmanship or refuses to take a penalty as assessed by an umpire, the umpire may fly a Black Flag, disqualifying them from the race.

While there are differences at each event and in each discipline, these general guidelines are followed in most umpired races, with specific flags used at various events, generally depending on availability.

With that, we have made it from land, through the start, a few general recalls, all the way to umpire flags! I hope this has helped you get a grasp of the various flags used across sailing. While this has not scratched the specifics of the various alterations made for kiteboards and windsurfers, nor some of the annoyances of protest flags and more, we have gone through the bulk of regularly used race committee and umpire signals.

The ‘Wear Your Life Jacket!’ Flag

Finally, we have a safety flag. At big boat regattas, the race committee may, if it chooses, fly the Y Flag at any point prior to a start to inform competitors that they must wear personal floatation devices, which is not always strictly necessary.

The Most Important Flag

While I wish I could tell you that everyone uses their flags properly and accompanies them with the proper timing and sound signals, that is far from the truth. Everyone’s flag set is slightly incomplete or out of date, and invariably there is going to be a miscommunication somewhere, where the race committee forgets to put the I Flag up but really should have; I’ve certainly done that a time or two. Still, there’s nothing quite like being on the water, so, despite the endless mutual griping between racers and their race committees, hopefully everyone comes back to shore flying the ‘Happy Flag.’

Happy sailing!

I have been sailing since I was 7 years old. Since then I've been a US sailing certified instructor for over 8 years, raced at every level of one-design and college sailing in fleet, team, and match racing, and love sharing my knowledge of sailing with others!

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Using AIS and trackers when racing

Race tracker and Automatic Identification System (AIS) technology is becoming more and more prevalent in yacht racing. In this article I explore what these technologies can offer us, how they can be used to our advantage and some of the drawbacks.

The 2014-15 Volvo Ocean Race was often referred to informally as the World Ocean Match Racing Series because the racing was so close between the teams. One of the reasons for the close positions of the boats was because they could keep one eye firmly on the opposition using AIS technology. Once out of AIS range of each other (approximately 8 to 12nm) the Volvo Ocean Race fleet had to revert back to the standard six-hourly position reports because they were prohibited from using three-hourly tracker data. Using the six-hourly reports meant that the fleet would split in a more traditional manner.

However, in many other ocean races these days, the Notices of Race require more regular position reporting for media coverage. This has seen trackers bridge the gap between near-live AIS positions and the six- hourly position reporting from traditional radio schedules.

What IS AIS

AIS came about because of the need to identify large vessels in commercial shipping zones. It provides critical data to captains to help them avoid collisions.

AIS uses a GPS receiver to obtain the vessels position and an AIS transponder which broadcasts that position via VHF radio. On the other end of the broadcast, an AIS receiver receives the position and boat's MMSI number. Other useful data such as vessel length, vessel type, speed, heading, rate of turn, etc. are also broadcast. This data can be provided either in a table or as a direct chart overlay.

AIS broadcast requirements are broken down in to two types, Class A, and Class B. Class A is required for commercial vessels. It has a broadcast rate of a few seconds and high transmission power of 12.5W. Class A broadcasts have other legal requirements such as monitoring. Class B requirements, which are the type which will be the focus of this article, typically have a refresh rate of around 30 seconds and a transmission power of 2W.

USING AIS WHEN RACING

For yacht racers, AIS can give you some very useful data for keeping an eye on your fellow competitors. It is possible to infer tactical information from the data. For example, a lift or header can be inferred based on their boats heading, or an increase in wind strength based on their speed.

What is Yellow Brick tracking?

Yellow Brick trackers have become the gold standard of race tracking over the last few years. Almost every major race now uses the “Yellow Bricks”, so named for their bright yellow colour and size similar to the old Nokia brick phones. The manufacturer of Yellow Brick trackers recently changed their name to YB trackers.

The YB trackers use the Iridium satellite service to track the position, SoG, and CoG of each yacht, typically at 15 minute intervals. These data are then overlayed on to a “Google maps” style chart which can be embedded into the event website. There is also a smartphone app for displaying the data on the go.

With some handy safety features such as a distress button, and a battery life of around three weeks (on a 15 minute refresh rate), many race organisers now use YB trackers as their primary way of keeping tabs on the fleet. As a result of YB trackers and similar trackers, many race organisers now use only “listening” schedules rather than a full position roll call for their races.

Tracking in Expedition

Those who watched the Whitbread Round the World Race as a child like I did will remember the daily position reports. The navigators came on deck and read out the gains and losses to each boat after the radio schedule. Nowadays with AIS, YB trackers and six hourly position reporting, it is near impossible to keep up doing the calculations long hand. Imagine having to plot out each boat every 15 minutes based on its YB tracker position… too hard right?

Fortunately Nick White, the author of Expedition (possibly the most widely used race navigation software in Australia) has written tools to update positions automatically for you using AIS and tracker data.

By linking your AIS system to Expedition, you can nominate the MMSI numbers of the yachts you wish to track. Then Expedition will give you critical performance data for those yachts. Automatically you will get each yacht's range, bearing, SoG, CoG, and VMC (velocity made good on course). Over the course of the race, this develops into an almost real-time plot of your competitors on your chart. Expedition can also track your competitors' two, five and 10minute average CoG, SoG and VMC so you can see any trends.

Once the AIS drops out of range (hopefully because you have pulled away over the horizon) you can switch to the YB tracker data.

All you need is the yacht race YB tracker race ID. For example, this year's Sydney to Gold Coast race ID was SGCR2015. Enter the YB race name, and Expedition will update the boat database, and display the relevant yachts' positions on the chart. You can then use the “race schedules” feature to display a whole raft of information such as the competitor’s ranges, bearings, CoG, SoG, VMC, as well as distance to finish (DTF), gain/loss, and even their position on corrected time

Which one to use and when?

AIS being near real time is useful only when in VHF range of the other boat. Its great for short haul races, and when close to other boats for shorter-term strategy.

Yellow Brick's 15 minute update, and straight in to expedition with a simple button click, is great for the duration of the race for both medium and long-term strategy against the fleet. It is also worth considering the update time of the tracker (usually on the hour, and then at 15 minute intervals) when making tactical moves such as a tack or a gybe. Doing the move just after the update may give you a 15 minute jump on the fleet.

Radio schedules every eight hours, are a last resort, and only really good for longer-term strategy. In most races we do around Australia, the time between scheds is too long to react to most tactical moves.

Is it good for racing?

Gone are the days where there are big splits in the fleet. Longer races are now effectively sprints or match races where you can’t lose your opposition. Many tactical opportunities that one would have taken before would now not be taken due to the risk of splitting with the fleet.

Will Oxley; navigator on board Alvimedica in the Volvo Ocean Race 2014-15 says, “I’d be happy getting a position report every 12 hours and nothing else. We often sailed our best when we were not obsessing about the AIS. However, AIS is a major safety improvement so I think we are stuck with it.”

I’d tend to agree with that. In my experience you often sail better sailing your own race. Given that this level of information is likely to stay, we need to learn how to use it to our advantage without losing the skill of tactical navigation. Sailing defensively has its place in offshore racing, but with AIS and trackers some of the tactical attacking skill has gone. Before the days of AIS and trackers you didn’t know where your competition was for certain, so their position played less of a factor in your decision making process.

Running tactical software for tracking is no longer just for the longer races. Learning to use the tracking features can give you some great tactical information on the rest of the fleet that will help get yourself in a better position. It is worth the investment to ensure you have a good system on board for receiving AIS information and a good Internet system for YB tracker data. But use it wisely, and keep sailing the fast route when you are confident in it, rather than defensively against the fleet.

Is defensive sailing from the moment you start a good idea? It is normally going to be better to be proactive in your decision-making than reactive. Use the tools wisely and at the best time for your strategy. ✵

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Thinking Like Your GPS System

By Dick Aarons
Updated: October 4, 2007

Today’s electronic navigation systems let you accomplish just about any navigation task in three or four ways. And therein lies the problem. Some of these systems offer so many options we can easily lose track of the fundamental task at hand: getting from point A to point B safely and relatively gracefully.

It helps to think of an electronic GPS or chart plotter as an assembly of four separate units: position finder, navigation computer, waypoint library and control display unit.

The position finder is the heart of the electronic navigation system. The important thing to understand is that the position-finder portion of GPS does nothing more than determine the current position of the vessel over and over again-usually at one-second intervals. These fixes are then sent to the navigation computer and the display unit of the GPS or the chart plotter.

As most of us know, the vessel’s instantaneous (current) position is displayed alphanumerically as latitude/longitude. If the system has plotting or charting capability, the current position will be displayed with an icon on the plotter/chart view. Most systems offer a “track mode that will display subsequent fixes. (Some users like to think of this feature as the “bread crumb mode.) You can turn it on and off and select the sampling rate.

To this point, our system is simply establishing positions sequentially and displaying them. Now we can really put the navigation computer to work and get the most out of these sophisticated units.

The first task of the navigation computer is to derive and display course over ground (COG) and speed over ground (SOG). Because the system knows where the vessel was a few seconds ago and where it is now, the navigation computer can approximate SOG and COG. “Approximate, of course, is the operative word. If the vessel is running at a constant speed and along a straight path, SOG and COG will be quite accurate. Alternatively, if the vessel is maneuvering and changing speed, the accuracy of SOG and COG calculations will deteriorate.

Your nav-system setup page will enable you to choose the COG display in true or magnetic degrees. For most navigators, true is the practical choice. The system will ask you to input the local variation or select an automatic mode that will provide variation based on your position. If you have a gyroscopic compass or flux gate on board, you will want to keep the displays in degrees true, to match your chart plots.

Though it seems obvious, it is important to understand that SOG is not necessarily speed through the water. SOG is a resultant of speed through the water, current and leeway. In a simple example, if your vessel is making 10 knots into the face of a 3-knot current, your SOG will be 7 knots. Similarly, COG is not necessarily the same as true or magnetic heading. Consider the situation in which you wish to track due west across a swiftly moving north-to-south current. While the COG will be 270T, your boat’s heading will be greater than 270T, because you must crab into the current to make good the desired course.

A sophisticated navigation computer can take speed through the water from a transducer and compare it with ship’s heading (from a compass system), SOG and COG to come up with current set and drift, a task that used to be hashed out with pencil, paper and calculator.

To this point, we’ve dealt only with the “where we are half of the navigation equation. The “where we are going half-obviously just as vital-involves waypoints.

Most systems allow you to define waypoints in several ways. Typically, you can enter lat/long of the desired waypoint or its range/bearing from your current position. Systems with plotting devices usually let you define a remote waypoint by moving a cursor to the appropriate place and pushing a button to capture and store the position. Most modern GPS systems have huge waypoint-storage capacities-1,000 or more is common.

Once you have defined a waypoint for your system, you can ask it to guide you there. This is one of the most common and easily understood functions of a GPS. As soon as you hit GoTo, the system begins computing a new collection of navigation parameters beyond SOG and COG. You may be able to see (or select) displays of ETE (estimated time en route), ETA (estimated time of arrival), TTG (time to go) and XTE (cross-track error). You’ll also have the opportunity to select new display types: CDI (course-deviation indicator) and BRI (bearing/range indicator). These are all functions that will help improve the system beyond getting from point A to point B, creating a more complete navigation tool.

Displays of ETE, ETA and TTG are instantaneous-that is, they are accurate if course and speed have been stable for a few moments and you continue to maintain your velocity. If you change speed, the system will recompute those parameters.

XTE is a measure of how far your vessel has moved left or right of the course that was established when you pushed GoTo. The lazy navigator’s method to remedy XTE is to push GoTo again. This generates a new track from the boat’s present position to the selected waypoint, eliminating the error. It is important to keep track of this information, ensuring you don’t wander over a navigational hazard.

The correct way to deal with XTE is to get back on the original course, then add a heading correction to keep your vessel on track. Your correction angle will be proportional to your rate of drift off course. Here’s a method some pros use to correct cross-track error:

1. The first step is to keep XTE from increasing. Make a 5- or 10-degree turn toward the desired track and hold the new heading while you monitor XTE. If XTE continues to grow, make another correction toward the original track, this time about half the magnitude of the first correction.

2. Once you have momentarily stabilized the XTE, your steering compass will indicate the corrected heading necessary to maintain the desired track when you get back on it. Now, turn toward the track, and once you have returned to it, turn back to the corrected heading.

This technique sounds a lot more complicated than it is in practice. Soon, you’ll be doing it automatically. In short, stop the drift, return to course and resume with the corrected heading. Use the CDI to visualize the rate of departure or closure to or from the desired track. Your autopilot can also be set up to interface with the GPS, monitoring the XTE. As with any piece of modern navigation equipment, however, it is important to understand the fundamentals. That way, you’ll know why your boat is changing course.

Finally, one waypoint you should know how to generate blindfolded is the MOB (man overboard) waypoint. Typically, the MOB waypoint is created when the user pushes MOB and holds it for a number of seconds, or pushes it a set number of times. The MOB waypoint automatically becomes the active waypoint; the displays direct you back to the place where you activated it, presumably where you lost somebody or something overboard.

One of the most beneficial elements of the modern GPS is the “route function. You can hook up a string of waypoints into a named route and tell the system to execute (i.e. follow) the route. In this situation, the system guides you to each waypoint in the route and automatically transitions to the next waypoint as the voyage continues. When running a route, your nav system will compute, at your request, the familiar nav parameters-SOG, COG, ETA, ETE and TTG-to the next waypoint or to the final destination. Make sure you know which waypoint (active or final) the system is using, and be sure you are still monitoring your course and changes in waypoint. It is often handy to have a waypoint list and check off each as you progress.

At any time, you can tell the system to skip a waypoint and proceed directly to another waypoint down route. You can also tell the nav computer to reverse the route and guide you back to the origin. Look at your owner’s manual for specifics.

Each nav system stores a finite number of routes, each with a finite number of waypoints. The specification will usually read something like “a maximum of 50 routes with 20 waypoints each.

USING YOUR SYSTEM

All electronic navigation systems do the things we’ve discussed. Where they differ is in the nuances of control and display. The best way to get to know your GPS and chart plotter is to use them at every opportunity. Have them up and running even when you’re cruising locally. Compare what you see on the displays with what you see and sense in the real world. Explore the menu pages and try different display configurations. Customize your display units to work with your charts.

The more time you spend with your GPS and chart plotter, the better they will serve you.

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Velocity Made Good (VMG) – Definition and Application

In this post we discuss Velocity Made Good or VMG. Many newer sailors are not familiar with this important concept, so we’ll discuss the definition and show some examples. Then we’ll discuss how to use the concept of target boat speed to maximize your VMG.

View the video or read through the text below.

Velocity made good is the speed at which you are making progress directly upwind or directly downwind.

Here’s an example with some made up numbers. The blue boat sails upwind on a close hauled course at about 45 degrees to the wind. The boat travels 7 units of distance in the time period, so we’ll say it’s boat speed was 7 units. The scale on the left shows that the boat traveled 5 units of distance upwind in the same time period. So, the boat’s VMG in this case is 5 units.

To show the importance of VMG, let’s compare the boat in the graphic above (Boat B in the graphic to the right) to two other boats sailing upwind.

Another boat (C) eases her sheets. C is reaching and sails faster, but at a lower heading than B. Her boat speed is 8 units in the same time period. She advanced 4 units upwind, so her VMG is 4 units.

Still another boat (A) decides to sail closer to the wind, so she sheets in tightly and heads up. She is pinching and her speed is 5 units. Her VMG is also 4 units.

These are made up numbers, but they illustrate that VMG depends on your boat speed and your heading.

Why is Velocity Made Good Important?

VMG measures how fast you are making progress directly upwind (or downwind). Therefore, if you’re sailing windward/leeward courses, the boat that has the highest average VMG wins the race. It’s that simple. If this puzzles you, go back and review our post on ladder rungs .

If the course is a reach, then VMG doesn’t matter – it’s straight line boat speed that matters.

Realize that it’s your average VMG that matters. You won’t always sail at your best VMG: sometimes you will pinch or foot, or even sail on a header to get to a favorable shift or puff. But if you find that favorable shift or puff, it will greatly increase your VMG.

Top sailors don’t spend a lot of time talking about VMG or trying to measure. The concept is important, but measuring it is not very important. To measure it, you need instruments that sense the actual wind speed and direction and track your progress upwind or downwind. Big keel boats have these instruments, but even for them, VMG changes so rapidly that it’s not useful.

Instead, we use other indicators to sail at max VMG. We’ll talk about these more below.

Maximize your VMG with Target Boat Speeds

One way to think about VMG is a concept called target boat speed. Keel boats use instruments to maximize VMG by sailing at target boat speeds.

To understand target boat speed, let’s review our previous examples.

Boat A had a boat speed of 5 and a VMG of 4.
Boat B sailed at 45 degrees to the wind and had a boat speed of 7 and a VMG of 5.
Boat C footed off and had a boat speed of 8 and a VMG of 4.

So, Boat B had the maximum VMG of these three boats. Let’s assume that B chose the very best combination of speed and sailing angle.

In the drawing above, notice the curve (dotted line) showing how far upwind boats would get if they sailed at different angles upwind. Assuming they were all trimmed up properly for their chosen headings, they would end up somewhere on the curve. This curve shows that a boat speed of 7 maximizes your VMG in this case. So, for this wind and these fictional boats, we would say that the target boat speed is 7.

So, the target boat speed is the speed at which your velocity made good is maximized for a given wind speed, assuming proper trim. If your boat is sailing above the target speed, like C, you’re footing. If your boat is sailing below the target speed, like A, you’re pinching.

Racing keelboats have instruments with target speeds programmed into them for each wind speed. On these boats, the helmsman and crew adjust the boat’s heading and trim until they match the target.

Target Speed and Puff Response – Upwind

When sailing upwind, many sailors have trouble getting the most out of the boat in a puff. The target speed concept can help you understand the best way to respond and maximize your VMG.

First, realize that target speed and heading angle are different for each wind speed. In our first example the target speed was 7. Let’s assume that occurred with the true wind at 8 mph and the heading of 45 degrees to the true wind.

If the wind increases to 12 mph, the target speed and heading will change. Let’s say that it changes to a target speed of 9 and a heading of 40 degrees.

Puff Response

If you’re sailing in an 8 mph wind and a puff of 12 mph comes along that lasts several seconds, how should respond to maximize your VMG? Should you head up to the 40 degree angle first? Or worry about the target speed?

If you think about target speeds, you will realize that your target boat speed increases when the puff hits, and so you must gain speed to get to the new target. If you head up first, you won’t build speed rapidly. You might even slow down if you head up too quickly.

Instead, you need to focus on getting to the new target speed as quickly as possible. Increase your speed by easing the sail and holding your heading steady or feathering up just a bit. During this speed building time, you’re sailing below the new angle of 40 degrees.

Once you build speed, you can head up fully to the new 40 degree angle.

Lull Response

Next think about the proper lull response. Let’s reverse the above situation. You’re sailing in 12 mph breeze at your target of 9, and along comes a lull to a wind of 8 mph. How should you react?

Hopefully, you can see that your new target speed is lower. To get to that new target quickly, hold your heading, even though you are sailing too high for the 8 mph wind. This will bleed off your speed quickly, and also let you make more progress upwind for a short time. Once your speed is down to target, you can bear off to the lower heading.

Maximizing VMG Downwind

just like upwind, there is a target boat speed and sailing angle that maximizes your velocity made good downwind.

In light air, most boats sail very slowly if they head dead downwind. To compensate, we head up to gain speed. The extra speed more than compensates for the extra distance we sail. Using made up numbers, if the wind were 4 mph, we might sail at a heading of 135 degrees to the wind to build to a speed of 3 mph. Boats that sail low might point closer to the mark, but make less progress. Boats that sail higher will go faster, but will also make less progress. This relationship is indicated by the dotted curves.

In heavier air, we can sail lower and still maintain higher speeds. In this example, if the wind is 8 mph, we might be able to sail dead downwind at 5 mph, maximizing our VMG. Thus, the dotted curve for 8 mph show a max VMG when heading straight downwind.

This is one of the reasons for the downwind advice to “sail up in the lulls and down in the puffs.” Following this advice blindly is not the best way to maximize VMG.

Puff and Lull Response Downwind

If you’re reaching up a little to get more speed in light air, and a puff comes along, should you head down immediately?

Just like the upwind response, the answer is to adjust your trim and hold your heading or feather down only slightly to build to your target speed as quickly as possible first. Then head down.

For a lull, bleed your speed while gaining distance downwind, before you head up. This might only take a few seconds.

Notes About Target Speed

Don’t worry about the math and geometry. It’s the concept, that there is a best speed and associated heading angle to maximize your VMG. The sailors that keep their boats at or near target speed will make the most upwind or downwind progress.

Since we don’t have instruments, we need other cues to tell us when we’re at target speed. Here are some:

The target speed concept is based on sailing your boat as fast as possible for the heading – that means proper sail trim, angle of heel, and hiking. If you’re not doing that, then by definition you’re not sailing at target speed.
Once you learn how to responds to puffs and lulls properly, you will feel the difference and will want to get that feel every time.
You can always tell if you’re gaining on other boats by comparing ladder rungs. See our video on ladder rungs for how to do this.

“Fudging” on Target Speed

Of course, there are situations when you may not want to sail strictly at target speed. These include the following:

Tactical or strategic positioning situations
Waves, where you might want to foot a bit to power through
Cases in which your boat’s speed limits (such as hull speed) and performance characteristics blur the target speed concept. We’ll discuss this idea in another post.

VMG (Velocity Made Good) – eye-catching video from Oracle Team USA VMG to Wind Calculator – just for fun from L-36.com

Understanding apparent wind: visual resources.

Mechanical Advantage in Sailboats: Block and Tackle Systems

4 thoughts on “velocity made good (vmg) – definition and application”.

This was a great article/commentary. I have often heard the term but never really understood it until now. Thanks a lot. Adrian

Thanks for the feedback! Let us know what other content you’d like to see.

Bin durch Zufall auf Eure tolle ! Seite(n) gestoßen; was ich bis jetzt gelesen habe ist klasse – ich hoffe, ich kann meine Jungs jetzt besser überzeugen ! – is german ok here or are all you guys US and others ?

Welcome Klaus! Deutsch is certainly welcome! Happy to have you share any sailing tips that you have. -Rob

Understanding the IOR Rating System & Formula

August 25th, 2017
Yachtmaster

Although the magazines and marinas are full of flat designed, chined and wide-sterned modern yachts made to perform and host large volumes, a great number of yachts nowadays have their origins in the Seventies and Eighties as we call them “Classic GRP Yachts”. As I was roaming the jetties of my home marina I came to rest in front of such a very, very nice and well kept yacht: A German made Hanseat in blue.

She bears the distinctive shape of a whole class of yachts which defined the Seventies yacht design: The IOR-yachts. IOR? Most of you may know this fictional conversation very well by their own neighbours in the berth: “Ah, this is a nice, classic boat indeed!”, “Yes, I like her. Her lines. She´s an IOR-yacht!”, “Yeah, for sure!”. IOR. We are all too familiar with the wide bulky hull shaped like a tea kettle. But what does IOR really mean? Here´s a short but hopefully clear explanation.

History of the IOR-Rating System

First of all, IOR, the “International Offshore Rule”, was a rating system introduced in the Sixties when for the first time in history regatta-rules and handicap ratings of Europe (namely of the Royal Ocean Racing Club of England, RORC) and America (to be precise of the CCA, the Cruising Club of America) sought to standardize their set of rules to ensure a worldwide rating system for sailing yacht races. The IOR has been kept in place up until the early Eighties when it was superseded by the more technical and scientific advanced IMS and IRC-rating, which are in place still today.

The set of rules changed massively during the years as their trustees tried to keep up with the pace of yacht designers and boat builders who sought to interpret the rules in such a way that thy would make the fastest boats possible within this set of rules. In such an environment, as we all know from other occasions, the mind of the people does incredible things and so the IOR set of rules sparked a whole generation of naval architects to create yachts and hull shapes within this set of rules – leading to this one, very iconic feature of IOR-yachts: The tea kettle shape of the hull. But what´s to it?

Design Features of Sailing Yachts under IOR-Rating

Well, in short, the IOR called for short waterline lengths. It favoured yachts with a short waterline and penalized longer boats. But as we all know: The longer the waterline length, the fast the boat sails. By the same time, naval architects and designers of the boats tried to keep the wetted surface of the yacht as small as possible, shortening the surface area of both hull, keel and rudder blades.

The yachts had been fitted with a sharp bow and the distinct “cruiser stern” which bears a large overhang. Now, let´s cast off and get the sails hoisted. What happens? First of all, when the IOR-shaped boat is now sailing, it will start to heel to leeward as expected. Due to the unique wide girth, the “tea kettle”-hull will now immerse into the water. As you may imagine by looking at such a tea kettle-shaped hull, due to the unique design features of the IOR-shaped hull, the length of the waterline increases greatly thus “imposing” a larger hull and increasing speed. That´s the theory.

Implications of IOR-designed Hulls

It really worked well for a number of yachts and IOR proved to be the offshore rule setting off a huge wave of new yachts to be built and new races to be raced. But the IOR-yachts had also some unwanted implications and sailing characteristics which are nowadays considered frowned upon the least if not to say dangerous.

First of all, IOR-yachts are a kind of unstable boats in terms of seakindness. Due to the round chined hull and the wide girth, those boats are sailing massively heeled and are always in heavy motion even in lighter swell. Modern yachts with wider sterns and pronounced chines are heeling up to a certain point and will then sail very stable. Also, during the catastrophic events of the iconic Fastnet Race of 1979 more of those unwanted and possibly dangerous effects of IOR-constructions emerged in a way that the formula itself, its official role in regulating races and the design features had been abandoned by both the commissions as well as by the naval architects. If you want to dive deeper into this topic, there are numerous books and websites available.

In present naval design of yachts the IOR-inspired hull shapes have completely vanished. Although IOR-yachts have undeniable qualities in sailing hard upwind, they are nowadays considered too shaky in terms of sailing characteristics. Also, the somewhat narrow aft sections of these yachts do only leave space for quarter berths the best – best example here is the Beneteau FIRST 30 on which I did have the pleasure to make a 7-day-short dash to the Island of Bornholm (read the full articles here and here ). This yacht offered way more comfort and volume on 30 feet than my 33 feet IOR-era King´s Cruiser 33.

So in the end, the IOR-era was an attempt to flatten the worldwide rating systems to pave the way for a global racing circus. Designers reached out far to squeeze out the best designs possible. In a way the IOR proved that a bright mind can create miracles even inside the narrowest borders. But IOR also proved that too many rules can have limitations and even dangerous aspects as well. I personally admire some of the IOR-era designs, such as my own boat – but I also praise the technological advance that brought us faster, safer and beautiful designs as well.

Other interesting articles on that topic:

What´s the Yardstick rating system all about?

Tim Kroeger on racing the Swan 60 .

Sailing a Pogo 40 Racing Yacht.

What is Yacht Racing? (Here’s All You Need To Know)

Have you ever watched a yacht race, with its colorful sails gliding across the water in a graceful dance? Have you ever wondered what it takes to participate in yacht racing? This article will take you through all you need to know about yacht racing, from the different types of yachts and races, to sailing clubs and regattas, technical knowledge and skills, safety, and the benefits of yacht racing.

We’ll also explore some of the most popular events and races.

So whether you’re an avid sailor or just curious about this exciting sport, you’ll find all the information you need here.

Table of Contents

Short Answer

Yacht racing is a competitive sport and recreational activity involving sailing yachts .

It is most popular in areas with strong maritime cultures, such as the UK, US and Australia.

Races typically involve a course that boats must follow, which can vary in length depending on the type of race.

Competitors often use advanced sailboat designs, and use tactics and strategy to try to outmaneuver their opponents in order to be the first to cross the finish line.

Types of Yachts Used in Racing

Yacht racing can be done with a wide variety of boats, from dinghies and keelboats to multihulls and offshore racing boats.

Dinghies are small, lightweight boats with a single sail and are often used in competitive racing.

Keelboats, on the other hand, are larger and heavier boats with a fixed keel and two or more sails.

Multihulls, like the popular catamaran, are boats with two or more hulls and are designed with speed and agility in mind.

Finally, offshore racing boats are designed for long-distance racing and are typically larger and more powerful than other types of yachts.

No matter what type of yacht you choose to race, they will all have common features that make them suitable for racing.

All yachts must have a mast, sails, hull and rigging, and will usually feature a deck, compass, and navigation equipment.

Additionally, racing yachts are often fitted with safety features such as life jackets, flares, and emergency radios.

Each type of yacht has its own unique characteristics, and some are better suited for certain types of racing than others.

For example, dinghies are better suited for short-course racing, while offshore racing boats are better for long-distance racing.

Additionally, keelboats and multihulls are often used for more challenging types of racing, such as distance racing or match racing.

No matter what type of yacht you choose for racing, it is important to remember that safety should always be your first priority.

Be sure to check the weather conditions before heading out and make sure that you have the proper safety equipment on board.

Additionally, it is important to get professional instruction or join a sailing club to ensure you have the necessary skills to race safely and enjoyably.

Types of Races

Yacht racing events can take place in a wide variety of forms and formats, from long-distance ocean racing to short-course inshore racing in protected bays and estuaries.

Each type of race requires different skills and equipment, and the type of race you choose to participate in will depend on your sailing experience, budget and the type of boat you have.

Long-distance ocean racing is a popular form of yacht racing, with races often taking place over several days and often involving multiple stages.

These races often have several classes of boat competing, with each boat competing in its own class.

These races may involve sailing around a set course or route, or they may be point-to-point races, where the boats sail from one point to another.

Inshore racing is the most common form of yacht racing, with races typically taking place over a few hours or a single day.

This type of racing is often conducted in protected waters, such as bays and estuaries, and generally involves shorter course lengths than ocean racing.

Inshore races may involve multiple classes of boat, or they may be one-design classes, where all boats are the same model and size.

Multi-hull racing is another popular type of yacht racing and involves boats with two or more hulls.

These boats are generally faster and more agile than monohulls, and races are often held over a short course.

These races can be highly competitive, with teams of experienced sailors vying for position and race victory.

Offshore racing is similar to ocean racing, but often involves much longer distances and more challenging conditions.

Races may take place over several days and multiple stages, and require a high level of experience and skill.

Offshore racing boats are usually specially designed for speed and agility, and may have multiple crew members on board to help manage the boat in challenging conditions.

Sailing Clubs and Regattas

Yacht racing is a popular sport around the world, with sailing clubs and regattas held in many countries.

Sailing clubs are organizations where members can come together to race, learn, and enjoy their shared passion for the sport.

Membership in a sailing club usually includes access to the clubs facilities, equipment, and training classes.

Regattas are large-scale yacht racing events, often hosted by a sailing club.

The regatta can be organized for any type of boat, from dinghys to offshore racing boats, and the races can be held over a series of days.

The goal of the regatta is to crown the winner of the overall race, or the individual class honours.

Sailing clubs and regattas are a great way for sailors of all levels to come together and compete.

They give sailors an opportunity to hone their skills, network, and make friends with other passionate sailors.

Additionally, these events are often open to the public, so they give the general public a chance to see the amazing spectacle of yacht racing up close.

If youre looking for an exciting and fun way to get involved with sailing, look no further than your local sailing club or regatta.

Technical Knowledge and Skills

Yacht racing is a sport that requires a great deal of technical knowledge and skill.

Competitors must be familiar with the physics and dynamics of sailing, including how to read the wind and manipulate their vessel to maximize speed and maneuverability.

They must also be able to understand the principles of navigation, so they can accurately plot a course and adjust it to take advantage of the prevailing wind and current conditions.

Furthermore, competitors must be able to read the weather and use that information to their advantage in the race.

Finally, competitors need to have a good understanding of the rules of the race and how to adhere to them.

Yacht racing is a complex sport with a steep learning curve, and it requires a great deal of experience and practice to master.

Safety is a key element of yacht racing, as it involves operating large vessels in often unpredictable and hazardous conditions.

All racers must be properly equipped with the appropriate safety gear, such as life jackets, flares, and a first aid kit.

It is also essential that all racers are familiar with the rules of the race, and have a good understanding of the safety protocols that must be followed in order to ensure the safety of everyone involved.

All yacht racing events must be properly insured, and there are often medical personnel on standby in case of an emergency.

Before any race, all participants must sign a waiver declaring that they understand the risks involved and accept responsibility for their own safety.

Benefits of Yacht Racing

Yacht racing is a great way to challenge yourself and take part in a thrilling sport.

It offers numerous benefits to those that participate, from improved physical health and mental well-being to an opportunity to travel and explore new places.

Whether youre a beginner or an experienced sailor, yacht racing provides an exciting and rewarding experience.

One of the main benefits of yacht racing is its impact on physical health.

It requires a great deal of strength and endurance, as the sailors must use their arms and legs to control the boats sails and rudder.

Its also a great way to get your heart rate up and improve your cardiovascular health.

Additionally, sailing is a low-impact sport, meaning theres less risk of injury than other more strenuous activities like running or cycling.

Yacht racing also has many mental benefits.

Its a great way to relax and take in the beauty of the ocean, as well as the camaraderie and excitement of competing in a team.

Additionally, it gives sailors the opportunity to put their problem-solving skills to the test, as they must think quickly and strategize in order to succeed.

Yacht racing also requires quick decision-making, which can help to improve mental acuity and develop a more acute awareness of ones surroundings.

Finally, yacht racing is a great way to explore new places and meet new people.

Races often take place in different locations around the world, meaning sailors can get a glimpse into different cultures and explore new destinations.

Additionally, yacht racing provides an opportunity to socialize with other sailors, as well as make connections in the sailing community.

Overall, yacht racing is a great way to challenge yourself and reap the numerous physical, mental, and social benefits that come with it.

With its exciting races and stunning locations, its no wonder that yacht racing has become a popular sport around the world.

Popular Events and Races

Yacht racing is an exciting and popular sport with events and races held all over the world.

From the world-famous Americas Cup to local regattas, there are races and events of all sizes and skill levels.

The Americas Cup is the oldest and most prestigious yacht race in the world, with the first race held in 1851.

Held every 3-4 years in a different location, the Americas Cup pits the worlds best sailors against each other in a battle of boat speed, tactics and teamwork.

The Rolex Sydney Hobart Yacht Race is another major race, held annually in Australia.

The race begins in Sydney Harbour and ends in the port of Hobart, Tasmania and is known for its unpredictable and challenging conditions.

The Whitbread Round the World Race (now known as The Volvo Ocean Race) is a grueling nine-month, round-the-world yacht race.

This race is one of the most challenging and dangerous races in the world.

In addition to these larger races, there are many smaller local and national regattas and races that offer an opportunity for sailors of all skill levels to compete.

From small dinghy races to larger keelboat and offshore racing events, there are plenty of opportunities to get involved in yacht racing.

Yacht racing is a fun, competitive and rewarding sport and with so many events and races available, there is sure to be something for everyone.

Whether you are a competitive sailor or just looking to have some fun on the water, yacht racing is the perfect sport for you.

Final Thoughts

Yacht racing is an exciting and challenging sport that is enjoyed by many around the world.

With a variety of yacht types, races and events to choose from, there is something for everyone.

To get started, it is important to have a good understanding of the technical skills and knowledge needed, as well as the safety protocols associated with the sport.

With the right preparation and dedication, yacht racing can be an incredibly rewarding experience.

If you’re interested in taking up this exciting sport, make sure you check out your local sailing clubs and regattas to find out what’s on offer.

James Frami

At the age of 15, he and four other friends from his neighborhood constructed their first boat. He has been sailing for almost 30 years and has a wealth of knowledge that he wants to share with others.

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05-06-2012, 13:45
	with 500 on MFD. is extreemly useful system. It doesn't replace radar/lights, eyes, etc. But is better than the rest combined. However, stalkers were able to track me up the coast on sites. and were surprised at my early arrival time. they said my speed was in the 4 to 5 range. Blasphemy! (shtarker)Ve don't do 4 knots here. So I am thinking it was transmitting speed rather than SOG. My speed was not calibrated and was showing 5 - 6 knots less than SOG in the . So, the question is does AIS transmit boat speed/heading or SOG/COG? One is accurate - the other can be completely wrong, and misleading from the perspective of another vessel. Also if you have receive only AIS - get transmit too - seriously you can be one of the ships or part of a ship... cheers

05-06-2012, 13:52
Boat: FP Belize, 43' - Dot Dun	. Yours will send heading if connected to a gyro stabilized heading source via (HDT sentence).

06-06-2012, 02:40

. Yours will send heading if connected to a gyro stabilized heading source via (HDT sentence).

06-06-2012, 11:49

Boat: FP Belize, 43' - Dot Dun

06-06-2012, 11:57
Boat: Research vessel for a university, retired now.	broadcasts COG, SOG and other information such as the vessels name, type of vessel and status. Some information has to be broadcasted for AIS to and some information is optional. AIS can be set up to broadcast heading from a gyro or a . This is optional information. Some vessels broadcast heading and some do not. An AIS receiver broadcasts nothing, by definition. It is listen only. Anton, please describe in more detail what you meant by your snarky comment. It wasn't of any help to DotDun.

06-06-2012, 12:02

06-06-2012, 12:15

Boat: FP Belize, 43' - Dot Dun

06-06-2012, 12:23

Boat: Moody 31

sites. and were surprised at my early arrival time. they said my speed was in the 4 to 5 range.
Blasphemy! (shtarker)Ve don't do 4 knots here.

06-06-2012, 12:34
Boat: Research vessel for a university, retired now.	to an AIS system is irrelevant. SOG is relevant.

06-06-2012, 13:41

to an AIS system is irrelevant. SOG is relevant.

07-06-2012, 05:43

07-06-2012, 07:06

07-06-2012, 07:30
Boat: Amel SM 53 - BeBe	. Get a life. Bill

07-06-2012, 07:34

Boat: Research vessel for a university, retired now.

. Get a life.

Bill

07-06-2012, 08:20

Boat: Amel SM 53 - BeBe

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Nautical Term: COG

Definition of cog.

Course Over Ground, often abbreviated as COG, refers to the true direction a vessel is traveling, relative to its actual heading. For instance, if a ship is sailing due west but its compass is indicating a northerly heading, then the ship’s COG would be due west. In a single paragraph, you could use the term COG to describe the true direction of a ship’s movement, despite its compass heading. For example, ‘Despite the compass indicating a westerly heading, the ship’s true Course Over Ground was easterly.’

Explore other nautical terms:

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What Does Cog Mean In Yacht Racing

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What does 'cog' mean in yacht racing - quora, cog boat abbreviation meaning - all acronyms, what are my electronics telling me about boatspeed and …, cog meanings | what does cog stand for - all acronyms, thinking like your gps system | yachting mag, cog - definition by acronymfinder, what does cog mean - imword.com, got enough information about what does cog mean in yacht racing.

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COGS the Cornwall Offshore Group Series

Welcome to COGS – the Cornwall Offshore Group Series.

COGS was founded in 2001 to encourage offshore yacht racing along the Cornish South coast and has since grown to offer an Offshore series of five races, a Coastal series of six races and – new for 2024 – a three race Bay series within Falmouth Bay.

All races are run with a fleet for IRC boats and another for boats with a RYAYTC handicap. IRC is a more technical rating system usually preferred by the “designed-to-race” boats, whilst RYAYTC, designed for cruisers and cruiser-racers, is simpler and free of cost. Within these two fleets, boats also have the choice of entering either fully-crewed or two-handed, with separate scoring and prizes for each group.

The Offshore series can take you around the Eddystone lighthouse, cross-channel to Roscoff or L’Aber Wrac’h, on a tour of the principal SW lighthouses (The Trinity) or on the PASAB race out to the Scillies, round the islands and back. The Coastal series is made up principally of passage races along the Cornish coast between ports from Plymouth to Penzance. Depending upon conditions, these races are perhaps less demanding and appeal to a wide range of cruiser-racers typically from 25 to 40ft alongside the more dedicated racers. COGS is “proper” racing conducted in good spirit and crews thoroughly enjoy the hospitality of ports and yacht clubs along with their racing.

Recognising the time pressures that may limit participation in the longer races, for this year we’ve introduced a separate three race Bay series within the Falmouth area and the Dodman (including the existing Gull Rock Manacles race, which also remains within the Coastal series). These races start between Pendennis Point and Black Rock, in the entrance to Carrick Roads, and finish off Flushing Sailing Club and so, for Falmouth based boats, eliminate the need to position for the start, or return home from the finish.

COGS is unusual in that it doesn’t run it’s own races. Each race in the calendar is run by a different yacht club which gives each event it’s own distinctive flavour. We’re very lucky to have the support of many excellent clubs who give their time and facilities to enable our racing. Our grateful thanks are due to these clubs and also to our race sponsors.

So, whether your preference is to race hard or to enjoy a “cruise with an edge”, and if your boat likes to stretch it’s legs beyond a short round-the-cans course, we’re confident that you’ll enjoy racing with COGS. Entering any of the series is simple and very good value, and we look forward to your joining us on the water in 2024.

Tim Rowley, Chair Anthony Nathan, Vice-Chair

Latest News

Offshore Series Final Placings

24 August 2024

As Trinity was cancelled today we now have the provisional results for the 2024 Offshore Series. Well done to Jackdaw, who won the IRC, Blue Horizon, who won the RYA YTC and Britich Beagle and Largo who won in the two 2H series,in IRC and RYA YTC respectively

Last Bay Series Race 8th September 2024

The SI are appended below, which are the same as earlier in the series

Trinity Race – Cancelled Due to Weather and Sea State

4 August 2024

Race abandonded by RCYC because of the weather and sea state The race will not be run on a future date as there is no suitable slot in the timetable, so the offshore series is now complete

Crewing On COGS Races

If you are interested in crewing on a boat in COGS races or if you are a skipper looking for crew, you can use the link below, which is the Falmouth Race Crew Wanted/Available Facebook site.

Alternatively, if you are looking for a COGS boat to crew on, you can contact the webmaster at [email protected], and your details can be circulated on the COGSChat WhatsApp Group

Important Note Re Offshore Series Entry Fees

Note that for the OFFSHORE SERIES you must complete your entry form and pay for the Series Entry (£30) and it is also necessary to complete the entry form and pay the individual entry fee via the organising club's website

SITE DESIGNED, DEVELOPED AND SUPPORTED BY EIGHT WIRE Pleased to support sailing in Cornwall

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What does COG stand for?

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Chicago style: Acronym Finder . S.v. "COG." Retrieved September 6 2024 from https://www.acronymfinder.com/COG.html
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BBYRA 2024 - 2025 Series

09/03/2024 - 06/06/2025, biscayne bay yacht racing association.

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Local yacht racing on Biscayne Bay is back!

BBYRA is excited to kick off the 2024-2025 season at our Skipper's Meeting, Awards Ceremony, and Crew Call; CRYC Reef Bar on Thursday September 12th, 2024 1800hrs. We hope to see you there!

Boat	Rating	Class
NEMESIS USA-1307		Etchells
Old's Cool 286		VX One
Wind Chill 7		PHRF (Certificate Required)
Cloud Nine 650		PHRF (Certificate Required)
Shadowplay 4208		J24

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This 32,000-mile Ocean Race has yachts doing research along the way
12-Meter yachts competing in the 1987 America’s Cup in Fremantle
A Look At The World’s 3 Biggest Yacht Races
Definition & Meaning of "Racing yacht"
Handbook on American yacht racing rules; an explanation of their
Schematic of speed over ground (SOG), course over ground (COG), ship

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COMMENTS

What does 'cog' mean in yacht racing?
In the world of yacht racing, the term 'cog' holds a special significance. Essentially, 'cog' is a nautical term referring to the course over the ground, the actual path that a yacht takes over the surface of the Earth. It's influenced by the vessel's heading and the current or wind. Keeping track of 'cog' is vital for navigational purposes and making strategic decisions during a race. So, in ...
What is the meaning of 'cog' in yacht racing?
In the world of yacht racing, the term "cog" refers to a boat's ability to sail at a certain angle to the wind. The concept of cog is essential to understanding racing strategy and determining the most efficient course to sail. Simply put, cog is the angle at which a boat is able to sail as close to the wind as possible while maintaining ...
How To Calculate Course Over Ground (Illustrated Guide)
Learn what course over ground (COG) is and how to measure it on a chart or with dead reckoning. Find out how to adjust COG for currents, leeway and other error factors.
Sail Racing Abbreviations and Acronyms.
SSS. "Safety and Stability Screening":- A base value for the boat is calculated from the boat's dimensions and rated parameters. STCW. "Standards of Training, Certification, and Watchkeeping":- A comprehensive set of international regulations that determine the qualifications and certifications required of seafarers.
What are My Electronics Telling Me About Boatspeed and Heading?
Learn how to use GPS units to measure speed over ground (SOG) and course over ground (COG) for sailing, and how they differ from speed through water (STW) and heading. Find out why paddlewheel and ...
Racing Terms: Glossary for Newer Sailors
Racing Terms and Phrases for Newer Sailors. The angle between the apparent wind and the chord line of the sail. The direction and speed of the wind as measured from a moving boat. Tacking away from other boats to obtain clear air. Often used for starting situations.
Key sailing terminology every sailor should know
Learn the key sailing terminology for meteorology, navigation, boat equipment, and more. This comprehensive list covers sail types, boat components, units of measurement, abbreviations, and unique terms for charter boats and safety at sea.
Racing Signals: Sailing Flag Meanings
Learn the meanings of all the flags used at regattas to communicate with sailors about starting procedures, course information, and on-the-water judging. Find out how to interpret the flags for different types of starts, penalties, and postponements.
Using AIS and trackers when racing
21/10/2015. Race tracker and Automatic Identification System (AIS) technology is becoming more and more prevalent in yacht racing. In this article I explore what these technologies can offer us, how they can be used to our advantage and some. of the drawbacks. The 2014-15 Volvo Ocean Race was often referred to informally as the World Ocean ...
Thinking Like Your GPS System
XTE (cross-track error) is a measure of how far your vessel has moved left or right of the course that was established when you pushed GoTo. Learn how to correct XTE and avoid navigational hazards with your GPS system.
Velocity Made Good (VMG)
VMG is the speed at which you are making progress directly upwind or downwind. Learn how to maximize your VMG with target boat speed, puff and lull response, and examples.
Understanding the IOR Rating System & Formula
First of all, IOR-yachts are a kind of unstable boats in terms of seakindness. Due to the round chined hull and the wide girth, those boats are sailing massively heeled and are always in heavy motion even in lighter swell. Modern yachts with wider sterns and pronounced chines are heeling up to a certain point and will then sail very stable.
What is Yacht Racing? (Here's All You Need To Know)
Learn everything you need to know about yacht racing, from the different types of yachts and races, to sailing clubs and regattas, technical knowledge and skills, safety, and the benefits of yacht racing. Whether you're an avid sailor or just curious about this exciting sport, you'll find all the information you need here.
Glossary
The Ocean Race is the world's premier offshore race, an exceptional test of sailing prowess and human endeavour, which started over 37 years ago as the Whitbread Round the World Race. The Ocean Race crews will experience life at the extreme as they race day and night for more than 20 days at a time, living on freeze-dried food and combating the harshest weather conditions the planet can offer ...
AIS
An AIS transceiver broadcasts COG, SOG and other information such as the vessels name, type of vessel and status. Some information has to be broadcasted for AIS to work and some information is optional. AIS can be set up to broadcast heading from a gyro or a fluxgate. This is optional information. Some vessels broadcast heading and some do not.
COG
Course Over Ground, often abbreviated as COG, refers to the true direction a vessel is traveling, relative to its actual heading. For instance, if a ship is sailing due west but its compass is indicating a northerly heading, then the ship's COG would be due west. In a single paragraph, you could use the term COG to describe the true direction of a ship's movement, despite its compass heading ...
COG Boat Abbreviation Meaning
Boat COG abbreviation meaning defined here. What does COG stand for in Boat? Get the most popular COG abbreviation related to Boat. ... Yacht Brokers, Designers and Surveyors Association. Broker, Business, Yacht. HT. Hard Top. Yacht, Business. BTW. Bearing to Waypoint. Sail Racing, Sail Sports, Sailing. FIA. Flight Instructor Airplane ...
Quora
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Cogs and other 12th century sailing vessels
Learn about the cog, a round-stemmed ship with a single square sail, and its contemporaries, the knorr and the nef, from the comments and questions of readers. Find out how many crew members, passengers and horses they could carry, how they manoeuvred and docked, and what routes they sailed.
What Does Cog Mean In Yacht Racing
COG Boat Abbreviation 1 COG Course Over the Ground Navigation, Course, Ground Navigation, Course, Ground Suggest to this list Related acronyms and abbreviations Abbr. Meaning Share COG Boat Abbreviationpage APA All Acronyms. 2021.
COGS the Cornwall Offshore Group Series
COGS offers three series of offshore, coastal and bay races along the Cornish coast for IRC and RYAYTC boats. Find out more about the races, entry fees, sponsors and yacht clubs involved in COGS.
COG
COG is an abbreviation that can stand for 71 different meanings, such as Cognitive, Children's Oncology Group, or Republic of the Congo. See the full list of definitions and categories of COG on AcronymFinder.com.
BBYRA 2024
Local yacht racing on Biscayne Bay is back! BBYRA is excited to kick off the 2024-2025 season at our Skipper's Meeting, Awards Ceremony, and Crew Call; CRYC Reef Bar on Thursday September 12th, 2024 1800hrs.