Professional BoatBuilder Magazine

Cfd for powerboat design, part 2.

By Clay Ratcliffe , Jul 20, 2021

CFD Modeling

Computational fluid dynamics (CFD) modeling of the aerodynamics of a Doug Wright Designs 32′ (9.75m) high-speed catamaran revealed that while it ran at 100 mph, air compressed between the hulls, deck, and water was creating a backflow high in the tunnel and leaking out the front to mix with the airflow over the deck.

CFD analysis of hull aerodynamics holds the potential to answer many performance questions, including the cause of an infamous side-by-side blow-over of identical high-performance catamarans during competition in Key West in 2019.

In Part 1 of our series “ Accommodating Higher Power ” (Professional BoatBuilder No. 191) we explored a case study of hull refinement and the practical application of recent advances in computer modeling to the art and science of hydrodynamics. Looking back at the traditions of modern boat manufacturing, we delved into bottom design, old-school versus new-school tooling methods, and learned how builders can update trusted hulls with improved running surfaces.

Here in Part 2 we’ll look at aero­dynamics—making improvements above the waterline. —Ed.

Eighty percent of the surface of a standard high-performance monohull or catamaran is out of the water, running through air. I remember as a kid putting my arm out the rear window of our car, twisting my hand right and left, and feeling lift and downforce for the first time. We all have experienced that exercise, and the aerodynamic laws we learned as kids hold true with any object surrounded by air. As boat designers and builders, how much attention do we give to that 80% of the hull surface, and how important is it?

Our Part 1 hydrodynamics case study vessel was a 32 ‘ (9.75m) Doug Wright Designs open-cockpit catamaran. We performed what CAD designers call reverse engineering. We started with an object in completed form, but we didn’t have modern triangulated point-to-point computerized coordinates to form a CAD file. Thus, with the aid of FARO Technologies (Lake Mary, Florida) we scanned the entire vessel to an accuracy of 0.004 “ (0.1mm). Then, with the help of Dimensional Engineering (Houston, Texas), we transformed the raw data into a full-mesh watertight stereolithography (STL) file suitable for the next step: computational fluid dynamics (CFD) modeling of the hull’s hydrodynamics and aerodynamics.

Airborne Racing Cat

When these boats are flying, as they frequently do during competition, tunnel pressure is released but must be quickly and smoothly reestablished when the boat recontacts the water. The risks are that while airborne the boats will either catch too much air and flip over backward or bury the bow when they land right-side up.

See the Air

Before working in performance boats, I was in auto racing and a fan of Dale Earnhardt. He often said he could “see the air” as he entered the corner. I remember watching him come in from the first 100 miles (161 km) of a Super Speedway at Talladega slouched down in the seat, five-point harness loosened, his hands loosely grasping two rungs of the steering wheel. He asked for 1.5 lbs (1.5 psi/0.1 bar) in the right-side tires and half a turn on the left rear suspension. He was conducting seat-of-the-pants “tuning,” because he could see (and feel) the air and the dynamics it had on an object slicing through it at 200 mph (322 kmh) on the back straight. Granted, in a boat we are aware not only of primary forces coming from the right and the left like a race car on a twisty high-speed road course but also oncoming waves, quartering seas, winds from all directions, and shifting loads that can move the center of gravity. But with 80% of the boat’s surface area in the air, let’s look at how we can “see” the air and modify it to enhance boat performance, efficiency, and safety.

From a camera’s point of view at the water’s surface it is easy to see that when traveling at speed, a high-performance catamaran is barely in the water. The weight supported by the water is close to zero, meaning the boat is actually “flying” on a cushion of air.

Headwinds and turbulent wave structures launch the high-speed catamaran and make it airborne often more than 50% of its operational duty cycle. Once the vessel launches, all the hydrodynamic hull design we refined in Part 1 is of little consequence until the next impact with the water. With engines mounted at the aft extremity of the boat momentarily unsupported by water, the stern drops, the bow rises, and the boat becomes an airplane in stall mode without the benefit of wings, ailerons, flaps, or other controls. If it doesn’t flip over backward, it then crashes back into the water transom first, tripping, and then risking stuffing the bow torpedo fashion in the wave ahead of it.

Key West World Championships

Dual Blowover

This simultaneous side-by-side blow-over during competition got the attention of the crowd and led driver Scott Porta, who was racing just ahead of the accident, to pursue CFD analysis of the dynamics between the two boats running at speed.

During the last Race World Offshore World Championships in Key West (November 6, 2019), an unexpected and unfortunate incident occurred in the Super Stock class race. Boat owners Bill Allen (Allen Lawn Care Race Team) and Loren Peters (Loren Peters Racing) were running side by side in two equally designed Doug Wright 32 ‘ race-prepared catamarans when they simultaneously flipped 180°, bow over stern. The accidental “blow-over” appeared to be choreographed. Fortunately, no one was injured, but many on the race course that day wondered how two boats running side by side could instantly go from running on a horizontal plane to vertical and then back to horizontal in a split second.

For the drivers, the experience was unbelievably fast and nearly indecipherable as far as aerodynamic analysis goes. Bill Allen (owner/throttleman, Allen Lawn Care Racing) recalled it like this: “I was a little short on room, and I don’t know if they didn’t know I was there or what…. I think, you know, that we got together, and it blew over. So, at the time that we made initial contact, we were at 106 mph. But I can say this, I guess in a boat race when you bump, stuff goes crazy.”

Loren Peters (owner/throttleman, LPC Racing): “Billy Allen was coming up on the starboard side.… I scooted over a little and Billy did the same thing. All of a sudden, we’re right up next to each other. We were deck to deck. I see Billy going up, and right after that, I felt lift. My life flashed before my eyes. We went completely over in a split second.”

Scott Porta (owner/throttleman, Porta Performance ) was throttling the catamaran just ahead. He describes the incident: “We were probably running 113 mph. The two boats just behind us were side by side trying to conduct a straightaway pass and positioning for the turn. These two [boats] naturally gathered up next to each other. The compressed tunnel air that normally escapes from under the sides of the boats was stopped when these guys got next to each other. The increased tunnel pressure easily pushed the bows up. Then the wind-drag and momentum took over. Think of it like when you try to slam a refrigerator door as hard as you can and the gasket traps the escaping air and prevents a hard closing of the door. The idea of boats gathering up next to each other and having a blow-over actually isn’t new and is common in single-engine tunnel boat racing. However, this may be a first for an offshore race.”

Porta’s ongoing efforts to refine the running surfaces of these Wright-designed catamarans for competition and recreational use were informed by this dramatic episode as well as by his own accumulated time behind the wheel on that model.

Porta: “Catamarans run on a cushion of air. There are physics issues we felt the need to address. With race and recreational cats running well over 100 mph, our mission has been to improve design: first, to create the largest possible margins for safety in turns and rough water; second, to design for softer landings to reduce driver fatigue and equipment failure; third, to reduce running surface drag for improved performance at lower trim angles. The resulting reduction in frontal area increases speed and stability while creating a larger window of safety. Aerodynamics is the next frontier to explore for the biggest possible untapped gains.”

To simulate the blow-over, we had two options: the conventional wind tunnel and model construction, or computational fluid dynamics (CFD). As in Part 1, CFD was the easy choice for obtaining results quickly and the ability to model subsequent design remedies. Again, we chose TotalSim US (Dublin, Ohio) as our technology partner.

Let’s review the particulars of the case study boat and the theoretical running conditions:

  •  Doug Wright 32 ‘ wide-tunnel catamaran
  •  5,000 lbs (2,268 kg) fully fueled, ready for passengers
  •  Twin Mercury 300XS engines (300 hp, approximately 600 lbs/272 kg each)
  •  Flat water
  •  Wind speed 0 mph
  •  Design speed 100+ mph (161+ kmh)

As speeds approach 100 mph, two primary dynamics contribute to lift and resultant speed on this model:

Engine lift—With a bullet-shaped gearcase and the X-dimension raised to a high level, a hydrodynamic phenomenon occurs. The half-submerged gearcase alone generates enough lift to carry the entire weight of the 600-lb outboard.

Hull lift—The shape of the catamaran tunnel captures and traps air between the sponsons, thus providing lift that supports most of the weight of the boat.

The CFD Assessment and Conclusion

Nathan Eagles, principal at TotalSim, and Scott Porta set out to see how the air currents at 100+ mph influence handling, speed, and efficiency of the catamaran. When Eagles saw the footage and spoke with Porta about the tandem liftoff at Key West, his immediate thought was to apply the tools and experience from other motor­­sports work to help explain why this happened and potentially develop some countermeasures that could reduce the risk of it reoccurring.

At the beginning of the project, Eagles offered a corollary: “Assessing safety and developing countermeasures to reduce the risks posed by aerodynamic forces when vehicles get outside their normal operating envelope is something the motorsports community has worked hard to address for many years. My initial foray was as head of CFD at the Williams F1 Formula One team, where I worked with the F.I.A. [Fédération Internationale de l’Automobile, the sport’s governing body—Ed.] to understand the forces acting on an F1 car as [it] pitched nose up, and at which angle the aero forces overpowered the weight and inertia forces.”

Later, during the development of the aero kits, TotalSim responded to one of the requirements imposed by Indycar. When the nose pitches up, the new bodywork was to be more stable than its predecessor while traveling sideways and/or backward. This meant that as the shape and the form of the car developed for efficient downforce and drag production around the track, TotalSim had to make sure the forces and moments acted to ground the car if it got airborne (its aero kit won the 100th running of the Indy 500 with no serious accidents).

Blow-Over Model

Angles Assessed in Blow-Over Model

The first step in analyzing the Key West event was to understand the typical forces and moments acting on the Doug Wright 32 when running where Porta was out in front and on his own. To do this, Eagles took the same geometry file Dimensional Engineering had created from the FARO scan and built a CFD model that focused only on the surface in contact with the air.

Eagles: “We set the angle of the hull relative to a flat sea state at several positions (Figure 1) and then assessed the forces and moments at each of those positions (Figure 2). The key forces under consideration are the drag (force acting against the forward motion) and lift (vertical force pushing up away from the water). The result of the combination of the lift and drag forces was a pitching moment (nose-up) about the center of gravity created by these forces.”

We can see from Figure 2 that as the angle of the isolated boat increases from 0° to 50°, the drag and lift forces (and resultant) increase as well, as does the pitching moment. We also see that the resultant is nonlinear, meaning that as the angle changes, the curves get steeper, indicating that doubling or tripling the angle more than doubles or triples the forces and moments. This characteristic implies gross instability, because once the aerodynamic forces exceed the weight of the boat and the bow starts to lift, the forces continue to increase at a rate that makes correction exceedingly difficult.

Angle of Attack Single Boat

Attack Angle Influence on Lift, Drag, and Pitching Moment of Single Boat

Having established the characteristics of the isolated boat, the next step was to place the boats side by side to see if anything changed. From the footage and the comments from the pilots, Eagles positioned the virtual boats 3 ‘ (0.91m) apart, set the angle of attack (AOA) at 5°, and ran the simulation. Figure 3 shows the same isolated boat forces and moments with the two-boat simulation data super­imposed on top. The results are quite dramatic.

We see both drag and lift increasing compared to the isolated boat, with the drag on each of the side-by-side boats being equivalent to the drag on an isolated boat at around a 7° AOA (suggesting they may be slowing each other down), while the lift of the side-by-side boats is equivalent to an isolated boat at around 16°.The huge changes in lift and associated pitching moment change are greater than the restoring moment of the weight, so the boats are no longer trimmed out, and the bows begin to rise.

Angle of Attack Two Boats

Dynamics of a Single Boat vs Boats Running Side by Side

As we saw in Figure 2, as the angle increases, so do the forces; and as the bows come up, the forces go up, the bows rise some more, and this continues until the boat flips over. The CFD force data illustrate a dynamic that would lead to the event we saw in Key West. But why did it happen?

This is where CFD really starts to show its strengths. The forces we have looked at are a result of pressure changes on the surface of the hull. These changes are created by local accelerations and decelerations of the air as it washes over the hull and deck, and CFD can show us how and why these occur. In Figures 4a and 4b the underside of the hull colored by the component of pressure is creating lift for the two different configurations. Yellow depicts low amounts of lift; red is high lift; green is low levels of downforce (the aerodynamic force pulling the boat toward the water); and blue is high downforce.

CFD Lift, Drag, Single Boat

CFD of Lift and Downward Force on Single Boat

The plots show that the entire tunnel surface is creating lift whether the boat is alone or side by side, and there is not much change between the two scenarios. However, the sponsons tell a different story. The isolated boat is showing strong downforce coming from both sponsons at the section just ahead of where the hull meets the water (blue patch midway down the sponson). This downforce is generated by the air accelerating in the narrowing gap between the hull and the water surface. This is illustrated in Figure 5a as velocity vectors colored by speed, with blue showing low speed and red showing high speed.

Eagles: “As air enters the tunnel, it starts to slow down as it packs up under the boat, and as it progresses it gets squeezed into a tighter volume and starts to push out at the sides, accelerating (red arrows) as it washes outboard over the hull surface. As the air accelerates, its pressure drops, creating suction, and this in turn generates a force pulling the hull towards the water. There are some effects also happening on the deck side, but these are secondary compared to the hull and have not been covered here.”

CFD Lift, Drag, Twin Boats

CFD of Lift and Downward Force on Boats Running Side by Side

Looking at the side-by-side configuration in Figure 4b, we see an effect on the outer sponson similar to what is seen on the isolated boat. However, on the inside sponson we see most of that downforce has been eliminated and replaced by lift across the majority of the surface. This is the source of the liftoff mechanism that caused the blow-over. The velocity vectors of the side-by-side configuration show that air is unable to get out as effectively, as it’s blocked by the sponson of the adjacent boat, as illustrated by the slow-moving blue arrows in Figure 5b. This slow-moving air has higher pressure and therefore does not create the suction we saw in the isolated boat, with the net result that the inside sponsons on both boats now create significantly more lift, disrupting their stable trim and causing the bows of the nearly identical hulls traveling at the same speed to flip quickly and almost simultaneously.

CFD Single Boat

CFD of Air Velocity on Single Boat

“The simplest way to reduce the risk of this happening in the future is to make sure there is sufficient gap between boats that the air can get out,” Eagles said. “However, racing being racing, when you are fighting for the patch of water leading around the buoy, I suspect that this probably will not be what is at the forefront of your thinking.”

He concluded: “A more practical solution would be to adopt something like Indycar or NASCAR and add a device to the boat that when deployed creates a counteracting force that cancels out the lift and stabilizes the pitching moment. This could be a passive device [auto-deploying] or active [driver initiated] and will require discussion with the governing bodies to make sure it does not adversely impact the racing or create issues of its own. I sense there might be a new project on the horizon.”

CFD Twin Boats

CFD of Air Velocity on Boats Running Side by Side

Real-World Aerodynamics

Most relevant to designers and builders of recreational powerboats, our case studies show that aero­dynamic design really starts affecting a boat above 60 mph (97 kmh). With multiple higher horsepower outboards being bolted on the transom, almost every boat manufacturer has a model capable of that speed, but aerodynamics are relevant on more sedate vessels as well. Builders use phrases like dry ride, acoustically tuned cockpit, comfortable, and wind free to describe the virtues of even a 20-knot boat. That’s no surprise when social media is full of posts about how “car-like” their recent boating experience had been. The current automotive comfort expectations have raised the bar for everyone. Gone are the days of the passengers in a top-down convertible being exhilarated by the wind in their hair on a gusty open highway. Modern convertibles are acoustically and aerodynamically refined. The open sky is still overhead, but engineering has all but eliminated the noise and wind of the convertible.

Let’s say that a boat owner drives to the marina in a quiet and aerodynamically refined convertible before boarding a newly acquired sport boat, a product that may cost twice or three times as much as the car. Shouldn’t expectations for comfort and noise be the same on the boat as in the car?

Jake Fraleigh, president of Eliminator Boats (Mira Loma, California), on the importance of aerodynamics to his recreational models: “In the past we used a higher deck, and we noticed that people in the back of our cockpits were getting lots of wind buffeting. Our newest models have flattened decks. We pulled the ‘bubble’ out of our top deck, and that allowed our new windshield design to positively affect our aerodynamics for cockpit comfort.”

Because Eliminator is installing more outboards, which means the boats go faster, Fraleigh said, “on both our 31 and 33, we are widening our tunnels now and changing the slope of the deck and tunnel entry, therefore creating more tunnel pressure. We have even added 45° angles to the sponson area upper-deck plane entering the tunnel for better entrapment of air under the boat. We have focused on more lift and therefore a faster, more agile boat.”

Nigel Hook, owner of SilverHook Powerboats (Sanford, Florida), confirmed the importance of CFD modeling during design and model refinement. “The SilverHook was designed as perfectly aerodynamic [with the help of CFD] by Ocke Mannerfeldt of the Swedish firm Mannerfelt Design Team. It has wings, although not movable; it has automatic stabilization. The consumer design has the same CFD advantage. It is fast, efficient, and safe. Only through aerodynamics are we able to manifest the true race-proven features.”

For now, the new minimum expectation for North American powerboat buyers is twin outboards, and the new normal is triples or quads on higher end vessels. More power adds speed, and with speed, airflow becomes very important to boat designers and builders. Boats can and do fly, if only for brief intervals, but managing their seakeeping, safety, handling, and comfort at those speeds requires as much attention to aerodynamic design and analysis as to hydrodynamics. To that end, more manufacturers are using CFD modeling to create and simulate the performance of any given design, especially as they pile on more power to meet market expectations. The results can range from understanding and correcting sources of dangerous instabilities and performance flaws, to quieting the ride in the cockpit and keeping the hair out of your eyes.

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For over forty five years the Bruce Roberts Group, with input from many designers, shipwrights, builders and owners, have been drawing detailed boat plans for sailboats and powerboats with the DIY boat builder specially in mind. These boatplans & designs range in size from 5.8 mts to 20 mts and can be built in many different materials.  We have boat plans & designs for building in steel or aluminium in either multichine, radius chine or round bilge hull forms.  Most boat plans & designs are also in fibreglass using either c-flex, foam sandwich or single skin hull construction methods or in cold moulded ply or strip plank using what is commonly know as wood epoxy boatbuilding. Thousands of boats marketed as Roberts designs have been built in backyards and successfully sailed around the world.

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Top 8 Best Boat Design Software in 2024 (Free & Paid)

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Written by: 3DSourced

January 16, 2024

Whether you’re a student, a hobbyist, or a professional, finding the right software is the key first step to designing a boat. However, with such a wide range of programs available, you need to make sure you choose the best boat design software for you.

We usually talk about 3D software in relation to 3D printing, but 3D modeling techniques are used across many applications and industries, including boat design. In fact, 3D printing is becoming increasingly prevalent in the boat design industry, with one example being Tanaruz’s 3D printed boats .

Quick Overview

  • Free!ship : Best Free Boat Design Software for Linux
  • Sailcut CAD : Free Sailboat Design Software
  • Bearboat SP : Free Boat Designer for Small Boats & Kayaks
  • DELFTship : Intuitive Free Boat Design Tool with Professional Option
  • Fusion 360 : Best Free Boat Design Software for Beginners & Mac
  • SketchUp : Best Boat Design App for iPad
  • Autoship : Best for Naval & Marine Architecture, Best for Windows
  • Solidworks : Best for Aluminum Boat Design Software & Best for Yachts

In this guide, we review several 3D ship design software to help you do just that. We’ll take a close look at both free and professional options, so that you’ll be able to find a suitable program regardless of your budget and experience.

Read more: our feature story on 3D printed boats

Best Free Boat Design Software

1. freeship – best free boat design software for linux.

Yacht designed in Free!ship

Completely free and open source 

Subdivision modeling to design any hull shape

Can export designs in a range of file formats

Can submit support and feature requests 

Positive reviews from users 

Can be tricky for novices to get used to 

Not available on Mac 

Unlike most of the boat building software on our list, Free!ship isn’t developed by a company, but rather by an individual called Marven with a desire to make boat design accessible to anyone.

Free!ship is a surface modeling program for designing ships and yachts, using subdivision surfaces modeling rather than NURBs, providing the freedom to design hulls of any shape. 

Available on Windows and Linux, you can get started with this free CAD software by automatically generating a basic boat structure to use as a template. You can then easily use the nodes on the structure, as well as a variety of tools like curve, split, collapse, and insert plane, to reshape the design to your liking.

You need to fill in certain parameters, such as:

  • Boat length
  • Beam length
  • Longitudinal and vertical direction

Once you’ve done that, you can view your boat design in four different perspectives and every angle to help you finalize your structure.

Free!ship offers the option to fill out support requests, feature requests, and report bugs. However, bear in mind that design beginners may be better off with a professional free ship design software that has more support options and tutorials available, as you don’t get any training with Free!ship.

2. Sailcut CAD – Free Sailboat Design Software

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Specialist sailboat design software 

Easy to use node editing

Supports a variety of sail designs

Export designs in different file types including DXF files

Not suitable for designing other boat types

If you’re looking for a free small boat design software specifically geared towards designing sails and sailboats, you can’t go wrong with Sailcut CAD .

This design and plotting software can be used to design the sail, hull, and rail of a boat, in addition to precisely computing panel development in flat sheets.

You can use it for a variety of different sail types, including wing sails, cross cut, twist foot cut, vertical cut, mitre cut, and radicul cut, so it’s a versatile tool that will suit virtually any sailboat designer.

The software provides a base design template that you can then edit and view in a variety of formats, including shaded, wireframe, and development. It provides control over all the key dimensions of your sailboat, such as boat length, gaff round, and seam width.

Sailcut provides documentation that explains how to use it for CAD as well as community mailing lists and a bug tracker where you can report issues.

3. Bearboat SP – Free Boat Designer for Small Boats & Kayaks 

Bearboat Software

Specialist kayak design software 

Simple to use 

Control all aspects of your design

Multiple view options

Advanced tools like wetting

Not suitable for larger boat designs

Dated interface 

Bearboat SP is a specialist kayak design software that can also be used to design other similar types of small boats.

People have been using Bearboat to design kayaks since 1998 – and it’s the most popular program for this specific type of boat design. 

It’s a fairly simple, no-frills software that makes it easy to get stuck straight in. You begin by filling in the core boat hull parameters, such as length, stability, and design deplacement, and then just click the ‘create’ button to generate your base kayak template. 

From there, you can go about making structural changes to aspects like shape seam, bow and stern seam height, and rockers parameters. You can also easily change dimensions using the nodes on the 2D wireframe design.

There are three viewing options – bird view, side view, and cross-section view – for inspecting your design from different perspectives, as well as options such as changing the color of the wireframe design for easier analysis. 

Advanced features include the ability to view the wetted surface and underwater area, and a drag spreadsheet that contains all the parameters of your boat design, making Bearboat SP a well-rounded boat design tool overall.

4. DELFTship – Intuitive Free Boat Design Tool with Professional Option

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More up-to-date and intuitive than other free boat design software tools

Impressive model rendering

Professional license and extension options

Perform basic calculations to check buoyancy and other factors

Free version has limited features compared to paid version

DELFTship is another great free boat design software, and offers a somewhat more professional and up-to-date solution versus Sailcut and Free!ship, with more impressive renderings than other free programs.

This 3D hull form modeling program is very intuitive with a range of easy-to-use design features, including lots of nodes that make it simple to edit your base model just by dragging and dropping.

You can inspect your models from five different viewpoints and convert them to wireframes and other formats to better analyze structure. Features like the keel and rudder wizard make it simple to design additional components of your boat.

DELFTship provides an unlimited free version alongside a professional license that costs $160. You can also add on extensions and board stability analysis calculations upon request for additional fees.

Even without the paid license you can still use DELFTship free to perform basic hydrostatic calculations and resistance calculations to help improve the precision of your designs, making this one of the most impressive free boat design tools. 

5. Fusion 360 – Best Free Boat Design Software for Beginners & Mac

powerboat yacht design

More beginner-friendly than other boat design software 

Lots of learning resources & tutorials

High quality, flexible 3D modeling tool

Impressive renderings

Available on Mac

Not a specialist boat hull design software

Unlike the other programs we’ve covered so far Fusion 360 is a general purpose 3D modeling software that’s not specifically made for boat designing. However, it’s still widely used in boat designing, and its more general nature has some advantages.

For starters, designing a boat is a fairly large and complex task, and the more specialist software like Free!ship and Bearboat SP are complex if you’re new to computer aided design. 

While Fusion 360 still has a learning curve, it’s one of the best designed, intuitive, and beginner-friendly 3D modeling software out there. On top of that, it has a huge range of learning resources and tutorials, great support, and a large user community, so it’s very popular among new designers.

In fact, there are a variety of YouTube videos and written tutorials showing how to use Fusion 360 for boat design and for different types of vessels, including yachts and canoes. These include videos showing how to design wooden boats , so it’s a good choice if you’re looking for a plywood boat design software.

Another benefit of Fusion 360 is that, unlike most naval architecture boat design software, it’s available on Mac. It even has iOS and Android apps that allow you to view designs and collaborate via your smartphone or tablet. 

Fusion 360 is also free for three years as long as you’re using it non-commercially.

Best Paid Boat Design Software 

6. sketchup – best boat design app for ipad.

  • Price : $119 a year for the app (free online version available)

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3D modeling iPad app

High quality renderings

Intuitive and beginner-friendly

Free online version available

Not specialized for boat design

SketchUp is another general purpose 3D software used for boat design. While it’s not one of the most widely used boat design programs, the reason it’s on our list is that it’s one of the few premier 3D CAD tools that has a fully-fledged mobile app for iPad.

While some programs like Fusion 360 have viewer apps, these don’t have the modeling tools of their desktop counterparts. However, with the SketchUp iPad app, you can enjoy advanced modeling on a tablet, and you can even get creative using an Apple Pencil stylus.

There are a variety of tutorials and videos showing how to design boats with SketchUp, and as a user-friendly software it’s a good option for beginners. SketchUp also boasts high quality renderings for producing 3D boat designs that you can easily share with anyone. 

While the SketchUp boat design app has a yearly fee, you can also use the software for free using the online-only version, or choose from a variety of desktop licenses that vary in terms of features and storage.

SketchUp also offers iPhone and Android apps, although these are more stripped back versions more suited to viewing and sharing designs on your mobile.

7. Autoship – Best for Naval & Marine Architecture, Best for Windows

  • Price : upon quote 

Boat designed in Autoship

Large software suite that covers the entire boat design pipeline

Used by professional boat manufacturers

Highly intuitive NURBs modeling

Comprehensive testing features and data management

Extensive training and support

Can be used to create load plans

Not available on Mac

Steep learning curve 

Autoship is a software suite designed for professional naval and marine architects that provides solutions for every aspect in the boat design process, from modeling to construction and load planning modules for more optimal loading.

In terms of design, Autoship software offers five different CAD/CAM solutions:

  • Autoship Pro – a hull design and surface modeling program.
  • Modelmaker – for creating 3D models of vessels and components.
  • Autohydro Pro – for analyzing hydrostatics and stability of your models.
  • Autoplate – a plate design, expansion, and management system.
  • Autopower – for resistance and powering predictions.

So, you can create a package with any number of these programs based on your needs. The great thing about Autoship software is all the programs are fully integrated, so any changes made to your model integrate into each solution.

Autoship Pro is the primary design solution in this suite, with a vast array of advanced features for designing vessels. Based on NURBs modeling, the intuitive interface allows you to work in up to four views simultaneously with ten levels of zoom and unzoom for top precision.

Some of the impressive features of this vessel design software include extensive context menus to help speed up operations, the ability to color surfaces so it’s easy to pick out parts in complex designs, curvature displays for curves and surfaces, hydrostatic and resistance calculations, and strength assessment tools.

Overall, with its mix of powerful design, testing, and engineering features, Autoship is one of the most complete boat design software on the market.

8. Solidworks – Best for Aluminum Boat Design Software & Best for Yachts

  • Price : upon quote

Yacht designed in Solidworks

Solidworks is one of the most advanced 3D CAD/CAM software out there and is widely used across design and engineering industries, from automotive to aerospace as well as boat design. 

In fact, this software is used by a number of leading boat manufacturers. One such example is Kvichak Marine Industries, a Seattle-based maker of high quality aluminum vessels, including both passenger and industrial boats.

In this v i deo , the assistant chief engineer explains how Solidworks’ highly precise 3D modeling tools allow them to improve processes by spotting issues quicker and therefore improve efficiency, with the ability to inspect every element from the individual pipes within hulls to the connections within engines.

Solidworks’ extremely advanced and flexible modeling allows you to create any type of boat you like. There’s even an eBook that explains each step in designing a superyacht using Solidworks.

While this software is mostly used by professional companies, there are also numerous YouTube videos showing you how to design a boat with it, so it’s accessible to amateurs.

What is Boat Design Software?

A boat design software is a program used to sketch, plan, and model a boat in 3D. Popular boat design programs include Free!ship, Solidworks, Fusion 360, and Autoship.

What is naval architecture?

Naval architecture is the processing of designing and engineering marine vessels like ships and boats, as well as their parts. Naval architects also work in boat and ship repair. 

Do I need special software for designing boats?

You don’t need a special boat design software to design boats and ships. While there are a number of specialist boat design software tools out there, general 3D modeling CAD programs like Fusion 360 and AutoCAD are also used for this purpose. 

What Can You Do With Boat Software? 

All boat software have different features that determine what you can do with them. For example, certain programs are designed for creating certain types of boats, such as kayaks and sailboats, so this is the first consideration you need to make to find a suitable program.

More expensive programs typically offer a much wider range of features than paid versions. At the top end are industrial solutions like Autoship and Solidworks, which offer extremely high quality and flexible modeling tools and provide support for testing, manufacturing, and engineering processes, so they’re complete solutions. 

There are also software like DELFTship and Fusion 360 that provide both free and paid versions, so you can try out the free versions and then upgrade if you want the extra features available on the paid licenses.

What Can You Do With Boat Software

Buying Guide – Things to consider when choosing boat software

Buying Guide-Boat Design Software

Type of Boat

Boats come in all different shapes and sizes, and some software are specially built for designing certain types of boats. For example, Bearboat SP is primarily geared towards kayak designing, while Sailcut is for sailboats. 

On the other hand, general 3D modeling software like Fusion 360 and Solidworks are more flexible, so you could use it as a Yacht design software and for other types of boats. The benefits of this are the increased flexibility and beginner-friendliness, but these general programs can lack some of the more specialist features that the likes of Bearboat SP and Sailcut have.


The device you’re using is going to have an impact on what naval architecture software you use, as most programs only work on certain operating systems.

In fact, the majority of boat design software are only compatible with Windows. If you’re looking for a boat design software for Mac, Linux, or iPad, you may be best off using a more general purpose 3D modeling software like Fusion 360 or SketchUp.

3D Rendering & Graphic Quality

Free programs like Free!ship, Sailcut, and Bearboat SP are all great for creating precise boat designs at no expense, but in terms of graphics and 3D model rendering, they’re all very basic. 

Yachts rendered in Solidworks and SketchUp

This isn’t unusual when it comes to free programs, and if you’re not bothered about graphics then it’s no issue. However, if you do want to create higher quality models and renderings – which is especially important if you’re a student or aspiring professional boat designer – then you’ll need a program that provides this, such as Solidworks or Autoship.

Usability & Training

Boat design isn’t exactly a simple process, so if you’re a complete beginner, you’ll want a software that’s easier to get to grips with. 

The free boat design software we’ve covered are all fairly simple to use, but the level of intuitiveness and support varies. If you’re a complete newbie to computer design, you may want to go for a widely used modeling software like SketchUp or Fusion 360, both of which boast great support, large communities, and more tutorials than specialist boat structural design software.

Budget & Free Trial 

The price of boat design software can vary a lot, from free programs to expensive professional solutions like Solidworks and Autoship that can cost thousands, so bear this in mind. Many paid boat design software offer free trials, so you should definitely take advantage of this to try a program out.

What software is best for basic boat design?

Free!ship, Delftship, and Sailcut are all popular free software that allow you to create basic boat designs. 

How do you design a yacht?

If you want to design yachts, the first step is to find a high quality yacht designing software such as Solidworks or Autoship.

How do you become a boat architect / ship designer?

To be a boat architect or ship designer you need to first obtain a relevant degree, such as a BEng or MEng in naval architecture.

How much do yacht architects make?

Yacht and naval architects can make anywhere from $60,000 to $150,000 depending on their experience and position, with the average salary around $75,000.

Autoship, Solidworks, Maxsurf, and OrcaFlex are all popular marine design software that are used in professional ship design.

To become a boat designer you first need a degree in a relevant subject, such as naval architecture, ship science, or marine technology. 

The best way to learn how to make a boat hull in Solidworks is by watching one the boast hull design tutorial provided by Solidworks Product Manager Mark Biasotti.

The first step to designing a yacht is finding a suitable CAD software, such as Solidworks or Fusion 360.

Lightning CAD Dock Designer is one of the most popular boat dock design software.

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Construction Album         Performance        Materials List         Builders Logs    

The Marissa is a smaller version of our Ocracoke 20 with an easier to build hull shape and a focus on efficiency. The design goal was for the most economical center console boat that would be just big enough to be really practical. By keeping the top end speed at 25 knots the structure could be made lighter which in turn means a smaller motor and less fuel are needed. Calculations show that at 15 knots (17.27 mph) with the 25 hp motor, the 16 gallon (60 liter) fuel tank will give a range of 210 nautical miles in flat water for 15mpg which is more than a lot of pick-ups can do. The top end speed with a 25 hp motor is 21 knots or 24 miles per hour burning 2.2 gallons (8.3liters) an hour. Most builders these days are choose 40-60hp since in many cases the higher hp motors are the same weight since they share the same engine block depending on manufacturer. 


LOA………..18′ 0″          5.49m LWL………..15′ 3″          4.65m BEAM…….. 6′ 10″          2.08m DRAFT/ hull.. 8 3/4″      22cm @ dwl DEADRISE at transom… 12 degrees HORSEPOWER…… 25 – 60  (20" motor) DISPLACEMENT 1680 lbs (764 kilos) @ dwl Pounds Per I” immersion 335#  (152kilos) Additional measurements: Cockpit depth measured at the lowest point..... 20 1/4"    51cm


"My 18' Marissa turned 4 in June and I just wanted to say it still brings a smile to my face the way it slices almost effortlessly through 2' short currituck sound chop. It is the driest boat I've ever had as well as very comfortable in most any direction sea. I don't even have to check the wind forecast before I head out on the sounds because I know, short of a hurricane or other storm it'll be fine. I finally got it dialed in with a brp rogue 13x17 4 blade prop last year and it's as close to perfect as a boat that size can be for me. The fuel economy is stellar as well, 5-6 gallons of gas and I can run all day."

The design was born as an answer to a Wooden Boat design contest. And she won! Read the article below here . This page is reproduced with permission from author Matt Murphy and Wooden Boat Publications. More pictures and video from the design competition here on . 


The construction method uses developed panels of plywood, built over a jig. This means that hull panels can be full size and will drape over the frame without having to be cut into smaller pieces. All of the “jig” becomes permanent structure.  The construction employs a modified “egg crate” method that is both light and strong.  The design is aimed at efficiency of materials for performance.  We also offer a CNC cut kit for these components for those that want to get a jump start on construction.   This is not a stitch and glue “introduction to building" type of boat however it is very suitable for the competent amateur. The Marissa is also an excellent choice for the small commercial yard.

Marissa Plans: Buy Plans

Plans include full size mylar templates for all of the parts in addition to Arch D size prints detailing construction. Below the "template guide sheet" indicates part placement using the templates for good use of materials. Sheets are pre-scarfed prior to cutting out parts from templates. 


CNC KIT:  For c urrent kit pricing  click here   The drawing below shows all of the plywood parts for the Marissa CNC kit. The kit uses 17 sheets of 3/8″ (9mm) 1 sheets of 1/4″ (6mm) and one sheet of 1/2″ (12mm).  All plywood is BS1088 Okume. The kit includes all of the hull pieces, (with all frames, stringers, floors etc..) including (shown below) the stem and keel and the center console. Note that the kit incudes some but not all of the solid wood required to complete the build because shipping solid wood in these long lengths is expensive and unnecessary since timber is almost always readily available locally to the builder. These include the side stringers, inwales, rub rails and stiffening cleats. These are locally sourced by the builder, ripped to size and scarfed to length.


We also offer an epoxy kit consisting of 21 gallons of epoxy, 3 pumps,  2 pounds of colloidal silica, 1 pound of microspheres, glass and tape.  The Kit is built on the cockpit sole where the frames fit into slots in the sole and the bottom stringers and keel slot into the frames.  Below, the Marisa Jig setup is very modest. A pair of saw horses and a few stiff legs do the job and 2x4 runners support the bulkheads. 


The details below show the unique step chine construction that we developed for this design. Instead of the chine log set “normal” to the side surface as is normally done, we set a chine batten “normal” (flat) to the bottom surface. This eliminates all beveling of the chine and gives a strong anchor to clamp or fasten the bottom to while the epoxy dries. The chine flat shape has been calculated and is machine cut or traced from the full size templates and rests on the frame flats until they are filleted. The side panels lay up to the chine flats and are trimmed to the flats after the glue dries. This method beside being fast to build will make for a very fair chine line and fairs right into the bow eliminating an unsightly unfair bow profile.


Hull #55 receives her flotation foam. The cockpit slopes aft and is self draining through transom scuppers. 


This builder added a dual console setup (below) to his Marissa. 

Click here to see more pictures of a  customized Marissa


Marissa Eco 18 Plans

Marissa: Study Plan (Download)

Marissa: Study Plan (Download)

Marissa 18 Kit Deposit

Marissa 18 Kit Deposit

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Boat Design Net

Island Design

Powerboat and marine design | architecture | graphic arts.


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    [1] 100 Boat Designs Reviewed Design Commentaries by the Experts (Woodenboat) on a number of boats from powerboats to daysailers and rowboats from designers including Howard Chapelle, John Alden, Henry Scheel, and Joel White.

  14. Top 8 Best Boat Design Software in 2024 (Free & Paid)

    Bearboat SP: Free Boat Designer for Small Boats & Kayaks. DELFTship: Intuitive Free Boat Design Tool with Professional Option. Fusion 360: Best Free Boat Design Software for Beginners & Mac. SketchUp: Best Boat Design App for iPad. Autoship: Best for Naval & Marine Architecture, Best for Windows.

  15. Power Boats from Van Gorkom Yacht Design

    VGYD have a diverse line of powerboat designs, from a powerful 28 foot cat hull, to a 36 foot jet-drive day launch, to a 50 foot house boat with a twist. ... The 48 Express Cruiser is an incredibly handsome and versatile yacht. Every feature of this design has been meticulously thought out, from the plush yet functional and light weight ...

  16. Scroll Down for Fiberglass Power Boat Plans

    BRUCE ROBERTS OFFICIAL WEB SITE powerboat plans power boat kits for steel boats or aluminum boat designs, cut to size boat kits, part built boats or complete boats. Bruce Roberts Yacht Designs offer boat building project management arrangements for boats built overseas at affordable prices. Sailboat and Powerboat building plans and kits available for building steel boats, fiberglass boats ...

  17. Build your own Power Boat

    Power Boats. A selection of plans for building your own power boat. Inboard and outboard designs are detailed. Horse power ratings, achievable speeds and water ski information are all included in the description of each plan. Blue Marlin 30. $ 185.00 - $ 200.00 (USD)

  18. Top 5 Powerboat Design Trends

    The opportunity for boat owners to enjoy a clean, quiet experience, especially with low-speed use such as moving in and out of marinas, is very appealing. ... 10 Powerboat Design Flaws to Avoid. 10 Top Boat Industry Trends in 2022. Motorboat Types: Powerboat Terms, Uses, and Definitions. Advertisement. Advertisement. About;

  19. Powerboats

    Marissa 18. The Marissa is a smaller version of our Ocracoke 20 with an easier to build hull shape and a focus on efficiency. The design goal was for the most economical center console boat that would be just big enough to be really practical. By keeping the top end speed at 25 knots the structure could be made lighter which in turn means a ...

  20. Powerboats

    Boat Design Net. Home Boat Design Forums > Design > Powerboats. Discuss production and custom powerboats and powerboat design. Propulsion (link) Surface Drives, Jet Drives, Outboards, Sterndrives, Pod Drives, Inboards.

  21. powerboat design

    powerboat design - yacht design - marine design (how to design a boat)

  22. Unsung Heroes of Yacht Design

    In 1977, when Jack Leek left Pacemaker to start Ocean Yachts, Martin went with him as principal designer and drew every Ocean for the next 30 years. Martin was a student of traditional powerboat design and studied the speed/power graphs developed by George Crouch, a professor at Webb Institute of Naval Architecture.

  23. Stylish New Italian Powerboat Is Poised To Meet Significant Demand

    Wally Yachts. Developed by Wally and Ferretti Group' s technical engineering department, the 43wallytender is constructed in advanced composites with carbon fiber at Wally' s new production ...

  24. Island Design

    The Boat Design Directory from Boat Design Net. Also powerboat and sailboat listings. [ view ] detroit river theater A br idge between layers of consciousness. prototype Concept to Creation - design, building, & testing. connecting liberation Infusing new life to old foundations. island design C A T 1 8 9.