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What Are Bulkheads & Stringers on Boats?

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An mnemonic for remembering shipboard terminology goes: "You lean on the bulkhead and stroll on the stringers." Bulkheads and stringers are boat parts that have on-shore equivalents. In spite of their odd names, they serve the same function as their counterparts ashore, as well as add to a boat's structural stability. Knowing that subtle differences marks you as a seafarer when you casually and correctly sprinkle these words in a conversation.

You Lean On the Bulkhead

A bulkhead is a wall. The American Merchant Seaman's Manual says that the bulkhead "provides privacy and encloses spaces within a ship." What the manual leaves unsaid is that the bulkhead is attached to lateral hull stiffeners in the same way that wall studs support a wall in a home. Although most bulkheads are thin, some -- like the collision bulkhead at the front of the ship -- are heavily made to withstand the pressure of the water in the event of a front-end collision.

You Stroll on the Stringer

The stringers are much like floor joists: they support the main deck and decks below the main deck. The stringers also provide room for concealed wiring that might run the length of the vessel. Stringers are concealed by the flooring on the decks below your feet and by the compartment "overheads," the ceilings of the cabins and compartments formed by bulkheads. The stringers provide a convenient attachment point for the overhead of a compartment.

The Bulkhead as a Structural Member

The bulkhead is loosely arranged as a shore-side home's wall, complete with a stud. Unlike a load-bearing wall of a home, the bulkhead doesn't provide structural strength. Instead, the frames that support the bulkhead, called bulkhead stiffeners, add the structure that surrounds a bulkhead. Some bulkheads, though, stand in the way of an invading ocean: should your boat become involved in a collision that breaches the forward end of the hull, the collision bulkhead stops water from entering the boat through the breach.

The Stringer as a Structural Member

Stringers run from the front to the rear of the boat's hull on all sides. One stringer is called the "keel." It runs from the bow of the boat -- the boat's front -- to the rear of the boat in the center of the bottom and acts as the backbone of the ship. Stringers placed between the frames around which a boat's hull is built provide longitudinal stiffness; they also keep the hull from bending in the middle like a rubber raft when the boat rides over a wave.

• "Section 15-01 The American Merchant Seaman's Manual"; W.B. Hayler; 1981

Will Charpentier is a writer who specializes in boating and maritime subjects. A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. He is also a certified marine technician and the author of a popular text on writing local history.

Watch: Bulkheads In Ships Explained

A bulkhead is a vertical partition wall subdividing the ship’s interior into watertight compartments.

Bulkheads reduce the extent of seawater flooding in case of damage and provide additional stiffness to the hull girder.

They can be flat or corrugated.

In simple words, a Bulkhead is an upright wall within a ship’s hull that separates the hull into different rooms and compartments.

Before learning the purpose and usage of the bulkhead on a ship, please subscribe to our channel and press the bell icon to receive future notifications.

The Basic Purpose of Bulkhead is to.

Increase the structural rigidity of the vessel: dividing a ship into smaller parts contributes to strengthening its hull.

Bulkheads also support the deck, making it sturdier and more damage-resistant.

Limit flooding by preventing loss of buoyancy: bulkheads can seal damaged compartments and isolate them from the rest of the ship. This way, the captain can keep the ship afloat while the rest of the compartments remain entirely usable (cargo, habitat, engine room) while it’s being repaired.

Divide functional areas into rooms and Compartments –

Dividing the hull into different sections allows seafarers to carry different types of cargo on the same vessel. This separation can have other purposes depending on the type of vessel. For instance, engineers use bulkheads to separate passenger cabins from crewmembers on yachts and commercial vessels.

Prevent the Spreading of fire: specific bulkheads can help contain fires on board. Similarly, floods in watertight compartments can be prevented; we can isolate fires from the rest of the ship by sealing bulkheads. Additionally, the crew can easily focus on their efforts to extinguish the blaze in that part of the ship.

Bulkheads are of different types according to their Purpose, Position, Or construction.

Some Important types of bulkheads are given below:

Longitudinal Bulkhead: extend fore and aft and divide the vessel along its length. Engineers use them inside traverse bulkheads to increase the number of compartments even further. As a result, the ship conserves even more buoyancy when specific compartments are flooded and isolated.

Additionally, they are one of the main construction elements that strengthen the longitudinal integrity of the ship and are essential in larger vessels such as tankers and commercial vessels.

Transverse Bulkhead: divides the ship from side to side and is used to create watertight compartments on the vessel. Additionally, they stiffen the hull’s structure, preventing deformation and racking stresses.

Plain Bulkheads: consist of plates stiffened by rolled sections such as bulb plates and angles spaced approximately 760mm apart.

The thickness of the plates is generally thickest at the bottom because of the maximum hydrostatic pressure experienced there, and thinnest at the top and typically not less than 6.5 mm thick. The plates of the bulkhead are laid in a horizontal direction.

Corrugated Bulkheads: They are Bulkheads with corrugated plating, eliminating the need for welded stiffeners. A corrugated plate is stronger than a flat plate without stiffening if subject to a bending moment or a pillar load along the corrugations.

The elimination of vertical stiffeners also results in saving in steel weight and the cost of stiffeners. The angle of corrugation is about 45 degrees.

Watertight Bulkhead: These types of bulkheads are used nowadays in almost all types of ships . They provide maximum safety in times of flooding or damage to the hull. They divide the ship into watertight compartments, which prevents water from seeping into other parts of the ship in case the hull breaks.

Collision Bulkheads: It is the foremost main transverse watertight bulkhead. It extends from the bottom of the hold to the freeboard deck or the forecastle deck and is designed to keep water away from the forward hold in case of bow collision damage.

The bulkhead shouldn’t be too much in front and be able to get damaged upon frontal impact.

Also, the bulkhead shouldn’t be too far aft to considerably allow the ship to trim by the stern when the section is flooded. In addition to obvious safety concerns, the captain can conserve fuel while heading back to shore when the ship is damaged. The bulkhead should also provide maximum cargo space.

After peak bulkhead: It is the bulkhead that forms the forward boundary of the aft peak. It can be flat or corrugated.

Engine room bulkhead: The bulkhead is transverse, either directly forward or aft of the engine room.

Bulkheads are the backbones of ships, providing strength and watertight integrity. Without them, we cannot imagine a ship working at sea.

Disclaimer:  The authors’ views expressed in this article do not necessarily reflect the views of Marine Insight. Data and charts, if used in the article, have been sourced from available information and have not been authenticated by any statutory authority. The author and Marine Insight do not claim it to be accurate nor accept any responsibility for the same. The views constitute only the opinions and do not constitute any guidelines or recommendations on any course of action to be followed by the reader.

The article or images cannot be reproduced, copied, shared or used in any form without the permission of the author and Marine Insight.

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Proper way to tab bulkheads on a fiberglass boat

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Hunters and other production boats seem to use a piece of roving, with no epoxy filler under it, to tab in bulkheads. I read somewhere that the lack of filler is to prevent "hard spots" in the hull. What are "hard spots"? Are these more of a problem on coastal boats with thin hulls than on quality boats with thicker layups? Better quality boats, such as C&C's, seem to use several layers of regular glass instead of a single piece of roving. Being opaque, I can't tell whether there is glue/filler at the actual joint and under the glass. Can anyone help me, what is the best way to glass in a bulkhead? If I wanted to add a bulkhead to my boat, should I do it "stitch and glue" style, with a bead of epoxy and filler covered by a few layers of glass cloth, or will that create "hard spots"? Roving would be easier to use, but it is considered inferior to several layers of say 10 oz glass by Don Casey. Is there a significant difference in strength and quality of the joint?  

I installed my new bulkheads with a strip of closed cell foam between the bulkhead and the hull or deck. This is to prevent the hard spots. The hard spots develop when the bulkhead is in actual contact with the hull or deck. Keeping a space with either foam or an epoxy filet is how you prevent this. I then used a couple layers of biaxial cloth and epoxy to tab it to the hull.  

Evidence of a 'hard spot' is when you can actually 'see' the location of a bulkhead from outside the boat.. most common with single skin hulls as opposed to cored, and most noticeable with a shiny hull surface.  

Actually, Beersmith said what I said and probably said it better... in about a third of the amount of wordage I used...bravo Beersmith!  

I have a couple of additions to the good advice listed so far. First, coat the surfaces of the ply, where the glass will go, with epoxy, BEFORE you start the installation - not just the end grain of the edge of the bulkhead. The wood will absorb some resin and if it's not precoated, it will have to pull this out of the first layer of glass, weakening this most critical bond a bit. Next, an easier method than Faster's slot method for anchoring the tabbing is to simply drill through the tabbing and bulkhead, after the glass has cured and been finished, and install appropriately sized machine screws. This bolts the tabbing and bulkhead together, preventing any movement which could cause delamination. The attached (poor) picture shows one of them beside the starboard chainplate. I installed eight of them like that, equally spaced on each bulkhead. Last, a very tidy and craftsman-like installation can be done one of two ways - install a slightly thinner than normal bulkhead and then epoxy laminate thin facing panels over each side of the bulkhead and tabbing strips so the total is the correct thickness for the bulkhead. Or; Rout a rabbet the width and thickness of the tabbing into the edge of the bulkhead before glassing. Either of these methods will keep the tabbing from sticking up above the finished bulkhead surface. Makes a very nice installation on bulkheads that show. Not worth the effort on hidden ones.  

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Sheathing Bulkheads, Part II: Fit, Glue and Finish

Last month, we showed you how you could turn a big, expensive pile of lumber into a smaller pile of bulkhead sheathing and a large pile of sawdust. This month, we’ll show you how to transform that pile of sheathing into beautiful new bulkheads for your boat. Like making the sheathing stock in the first place, installing it is a tedious operation, full of opportunities to make mistakes.

Undoubtedly, some of your pieces of sheathing will have flaws in them-poor grain, poor color, or knots. As much as possible, you should work around these flaws. In new construction, lay out on the unsheathed bulkhead the locations of furniture, cabinets, hardware, or anything else that will cover up any part of the finished bulkhead. With a little planning, you can hide most of the material flaws in location that won’t show when the boat is finished, such as inside lockers, or settee cushions. Unfortunately, you don’t always have that option in a retrofit. That’s one reason for making extra sheathing stock: the inevitable, badly flawed pieces can go unused.

Surface Preparation

Prepare the plywood bulkhead surface for sheathing by power sanding with coarse (60 grit) sandpaper. If the bulkhead is teak plywood, follow this up with an alcohol wipe down to remove surface oils just before gluing down the sheathing.

The tongue part of your sheathing stock has two purposes: to keep the joint between pieces of sheathing from oozing glue, and to assist in positioning and fastening the stock to the bulkhead. The bulkhead sheathing is attached using a combination of mechanical fasteners and adhesive. Epoxy resin, thickened slightly with a material similar in color to the sheathing (such as fine sawdust from making the stock, or a commercial thickener such as WEST System Tan Filleting Blend) provides the primary holding power.

Staples are used as mechanical fasteners and to hold the sheathing in position while the glue sets, but add little to the structural integrity of the installation. We recommend using an Arrow T-50 tacker with 3/8” monel staples. Do not use ordinary steel staples, and be sure to keep your monel staples clearly separated from any steel ones you have, since it is difficult to tell monel from steel without using a magnet.

You should not use screws to fasten the sheathing, except in areas where they are required to get the sheathing to lie down flat. Even carefully matched bungs in screw holes will detract slightly from the appearance of the bulkhead.

The first piece of sheathing installed is the most critical. It must be absolutely plumb, since the sheathing consists of a series of vertical lines which will look ridiculous if they don’t line up with the other verticles on the boat, such as door edges.

Begin next to a doorway to another true vertical, if possible. This allows you to clamp the first piece into position before gluing, so you can carefully line it up. It is best to overlap the doorway slightly with the first piece, since a joint in the sheathing which lines up with the edge of the doorway will look odd. You can trim off the overlap with a saber saw after the doorway is sheathed.

The tongue edge of each piece of stock is the working edge-the edge against which the next piece will be fitted. If you try to do it the other way around, you won’t be able to staple each piece into position.

Cabin overheads are almost always cambered in section to avoid a boxy look.

This slightly complicates fitting the sheathing tightly overhead. An adjustable bevel gauge can be used to take off the angle between the vertical simple thin cardboard template the width of a piece of sheathing, trial fitting to the top of the cabin using a mat knife and a straight edge. Cardboard templates are also useful when it’s necessary to fit around permanent joiner-work. It’s better to make cutting mistakes on cardboard than expensive wood.

Fitting at the bottom of each piece is the same as fitting at the top. Once again, patterns are helpful. If you’re sheathing a new bulkhead, you may have to relieve the back of each piece of sheathing to fit over the tabbing which holds the bulkhead to the hull. This can be done with a plane, chisel, or belt sander. In some cases the tabbing may be so thick that you can’t cut away enough material on the back to make the sheathing lie perfectly flat. You can get away with having it sprung out slightly, since the edges of bulkheads are usually covered with trim, or are hidden inside other furniture.

The top and bottom bevels are cut with a band saw, saber saw, or coping saw.

When you’re finished with the position of the first piece of sheathing, clamp it firmly in place on the bulkhead along the working edge of the sheathing as an alignment reference. For the second piece in the same fashion as the first, once again using clamps to hold it in position after fitting. From here on out, you won’t be able to directly clamp pieces in position. Instead, clamp a batten to the bulkhead long enough to reach over the piece of sheathing currently being fitted. A thin wedge under the batten will apply enough pressure to the sheathing to keep it from sliding out of place as you work.

We have found it best to install no more than four pieces of sheathing – about a foot of bulkhead width – in any one gluing. More than that becomes awkward to glue, clamp, and staple in place. It’s better to do the bulkhead right, a little at a time, than try to save time by doing it all at once.

You can fine tune the fit of sheathing at the overhead and bottom using a sanding block wrapped with coarse sand paper as a rasp. This is less likely to cause splinters than trying to use a tool such as a block plane or a Surform, and allows subtle shaping of the top to conform with the curve of the cabinet top.

After the last piece of sheathing for the first gluing is fitted, strike another pencil line on the bulkhead along the working edge of this piece. This will indicate the edge of the section of bulkhead to be painted with adhesive for the first gluing. Number the pieces before removing them from the bulkhead, either writing the numbers on masking tape stuck to the surface or by lightly penciling numbers on each face.

You’re now ready for the big test.

Since mixed epoxy resin has a short pot life, get everything ready before mixing up the glue. Lay the pieces of sheathing on a table covered with polyethylene sheeting, to which dripped resin will not stick.

Use either a foam brush or foam roller to coat both the back of each piece of sheathing and the face of the bulkhead. Coat both with unfilled resin first, then mix thickener into the resin and brush another coat onto the back of each piece of sheathing. The thickened resin should be the consistency of honey, so it can fill any gaps between the sheathing and the bulkhead surface. It should be brushed out fairly evenly, leveling with a wide putty knife if necessary.

Take your time to position the first piece of sheathing, being careful to line it up with the line you drew on the bulkhead as a reference mark. Use a couple of C-clamps to hold the piece of sheathing in position. Be careful, since the low friction resin-coated surfaces will want to slide around as you tighten the clamps. Use thin pieces of clean scrap wood under the clamps to keep from damaging the surface of the sheathing.

When the first piece of sheathing is clamped into position, staple the tongue to the bulkhead, using firm pressure on the tacker to driver the staples in as far as possible. The staples should be placed about a foot apart, as far in from the edge of the tongue as possible, with the long axis of the staple parallel to the edge of the tongue.

Even using a lot of pressure on the tacker, the staples will probably not drive all the way into the bulkhead. Use a ¼” diameter pin punch and hammer to set them flush with the surface of the tongue.

Aligning the next piece is easier, since it is simply butted up against the edge of the first, then stapled down. After stapling the edge of the second piece, you’ll notice that its groove edge – which is not stapled down – has probably lifted slightly, and is not lying down flush. This edge, and the corresponding edge in the next pieces, will be wedged down after all the pieces in a single gluing are stapled in place on the bulkhead. Now you see why it’s best to fit only a few pieces of sheathing at a time.

Attach the next piece or pieces in the same manner as the second.

You now must face the problem of making the sheathing lie down flat. This is accomplished using a number of battens about ¾” square, which can be made from any type of clean scrap. These are clamped to the edge of the bulkhead at the doorway, allowing them to overlap the last piece of sheathing on the bulkhead by a couple of inches. Drive a screw through the batten into the bulkhead just past the last piece of sheathing. The screw hole in the bulkhead will be covered by the first sheathing strake of the next gluing.

While the batten will do a pretty good job of flattening out the sheathing, you will probably have to use thin wedges or shims under the batten to really hold things down flat. By pressing on the face of the sheathing with your fingers, you be able to feel any sections that are not lying down flat on the bulkhead below. Add more battens and wedges as necessary to hold things down firmly.

Now clean up the mess of glue that has probably squeezed out between some pieces of sheathing and at the top and at the bottom of each piece. A rag dipped in stove alcohol or shellac thinner will remove gobs of epoxy from your sheathing. Use a putty knife to clean up glue that has squeezed past the edge of the last piece of sheathing, to leave the bulkhead clean for fitting and gluing the next the next pieces.

Cleanup is critical. The more effort you put into removing glue while it is still wet, the less work you will have when finishing the surface after the bulkhead is completed.

Always wears latex exam gloves when working with epoxies. A box of 100 costs about $1.5, and it’s the best $15 you’ll ever spend. Epoxy sensitization is permanent, and miserable. Wash any epoxy which gets on your skin off with soap and hot water before it sets up. Don’t use solvents to clean your skin unless absolutely necessary, and then use alcohol, not anything more powerful. Even alcohol has a serious drying effect on your skin.

Carrying On

Successive fittings and gluings generally get easier, although your hold-down battens must get longer and longer as you go.

A few screws through the sheathing itself will be inevitable, as it will undoubtedly be impossible to wedge some pieces completely flat, particularly at the bottom edges and at the extreme edges and at the extreme outboard edge of the bulkhead. Use as few fastenings as possible, and make them fairly large-diameter panhead stainless steel self tappers driven only flush with the surface. After the glue kicks, the fastenings can be removed and the screw holes counterbored and bunged with plugs cut from the same material as the sheathing. Do not use readymade plugs of what is nominally the same material as your sheathing, since the readymade plugs may b different in color from your own stock.

Work from roughly the centerline of the bulkhead all the way to one side, then work from the center to the other side. You will have to reverse the direction the tongue of the sheathing points when you begin working from the center toward the opposite side, since the tongue would otherwise be hidden. Do this by first gluing a thin “tongue” under the grooved edge of the first piece of sheathing you installed. You’re now ready to start gluing in the other direction.

When you’ve finished installing all the sheathing, your bulkhead will look pretty sorry. It will probably have edges which don’t lie flat, gobs of glue here and there, and torn out surface grain. The effort you will put into finishing turns this rough bulkhead into a thing of beauty.

Begin by machine sanding with coarse paper, gradually working from 50-60 grit down to about 100 grit. Use an orbital sander such as the Makita B04510 or the Porter Cable 330 Block Sander. You can use a block plane to cut down any badly raised edges which weren’t completely down. Don’t worry about them coming loose. Some voids behind the sheathing are inevitable, but they won’t affect anything.

After machine sanding, you must finish sand by hand, using a flexible rubber sanding block of the type used in auto body work, or a homemade block of cork or neoprene. Go back to 80 grit paper, sanding with the grain. Sand out any machine sander swirls on the sander swirls on the surface with 80 grit paper before moving on to 100, then 120 grit, but highly-figured wood must be further sanded with 150 and 180 grit to remove fine scratches.

We prefer a satin finish on interior woodwork. It hides flaws better than gloss varnish, an looks more like a traditional hand rubbed finish. If you’re a real masochist, varnish with gloss varnish until the grain of the wood is completely filled. Then rub down the surface with powdered pumice on a cloth dampened water or furniture oil. You’ll eventually get a beautiful surface unmatched in appearance, but at the cost of untold hours of labor. We’d suggest you try a hand-rubbed finish on something small, like a magazine rack, before committing yourself to doing something as large as a bulkhead this way.

For most of us, a satin interior varnish is more than reasonable substitute. Use at least five costs to fill the grain. Sand between each coat with 180 grit paper, using a tack rag to clean the surface just before applying the next coat of varnish.

Odds and Ends

In new construction, the edges of bulkheads are covered with a margin piece to hide any fitting errors or rough edges. The margin pieces should be of either the same wood as the bulkhead, or of a contrasting wood. The margin pieces should be fairly thin, and must be carefully fitted to the side of the hull. If ceiling is to be installed, margin pieces may be unnecessary, as the cleats for the ceiling will probably hide rough edges.

In retrofits, either reuse the original margin pieces or make new ones of the same material as your new bulkhead, using the old pieces as patterns. The margin pieces should merely be screwed on, either counterboring and bunging flathead screws, or countersinking oval head screws.

Sheathing bulkheads is not a beginner’s project. But with careful planning and cautious execution, it can give your boat an interior unmatched by the stick, run of the mill plywood bulkhead. And it will give you a great deal of pride in your boat.

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Proper way to tab bulkheads on a fiberglass boat

Discussion in ' Sailboats ' started by peterchech , Apr 25, 2012 .

peterchech Senior Member

If you look at a production boat like a Hunter, many of the structural bulkheads are tabbed in with one layer of glass roving. I don't see what looks like filler at the actual joint. I guess this is to prevent "hard spots", however that works... On a better quality boat like a C&C, it looks like they use several layers of maybe 10 oz regular glass. Being opaque, I can't tell whether there is filler at the joint or not. Say I wanted to add a structural bulkhead to my boat, or else reinforce an existing one. What is the best/proper way to attach the bulkhead to the hull of a glass production boat?  

souljour2000 Senior Member

I am not sure... but we will hear from the experts...I will say that I think a small fillet along the tabbed areas with a few layers of glass over it would be needed to reduce any bulkhead movement and seal joints to reduce moisture migration ...sealing the butt ends of the ply with epoxy is critical so it doesnt wick up moisture. Then consider leaving a small gap at where bulkhead, etc. panels meet the hull/coachroof that can be sealed as part of the epoxy fillet...and then tab over with light/heavy glass layers...  

gonzo Senior Member

It depends on the hull construction. Cored hulls don't usually get print through from hard spots. If the laminate is solid, it is common practice to either leave a small gap or have a foam tapered filler in between.  

What kind of foam would be used as filler? Mixed floation foam? Seems that would expand too much...  

iceboater Junior Member

I use carriage bolt (photo1) of different size to shape fillets from fiberglass bonding paste (photo 2) from Oldopal. I am not familiar with using expansion foam as filler, I think Gonzo means pre cut foam fillets. For glass over the fillet, I use any ware from 1800-4500 gr/m2 of glass (sorry, metric) tapered out each layer depending on the design. Axel  

Attached Files:

Screen shot 2012-04-25 at 9.39.27 pm.png, screen shot 2012-04-25 at 10.54.22 pm.png.

Yes, I meant precut foam fillets  

PAR Yacht Designer/Builder

A typical foam shape, used under the edge of a bulkhead, at the interface of the hull shell. Triangular shapes are common as are trapezoidal stringers. Any shape can be cut, though these can save time. A filler can be mixed as well, which serves the same purpose and commonly applied as a fillet or bedding under an element. As far as proper tabbing, well it depends on the loads. A single layer of fabric isn't uncommon. This doesn't mean it's very durable, just that it's an out of sight place manufactures can save some money. Directional fabrics are much better suited to tabbing than anything else. It's all I spec except on small craft where cloth will serve. If you could be more specific about your application, more precise answers could be applied. What ever it is, I'll probably tell you to use biax and epoxy, no mat. It's just easier, stronger, uses much less resin and isn't going to fail easily. As to how much biax, well this depends on the boat and the bulkhead.  

Well I ask for two reasons. I have a 1982 hunter 25 and have repaired cracked bulkheads on it before.I used the same method as I would on a s&g dinghy. An epoxy and hard filler joint, filleted to about 1/2 inch half round, then 2 layers of 10oz glass cloth. I was wondering if this is adequate, or whether the epoxy filler joint would create a hard spot or even a stress concentration point. The second reason I ask is because the owner of the Phrf boat I will be crewing on ripped out his interior and installed a "grid" of shallow bulkheads around the keel intersection area. I like this idea alot. I was wondering what the proper way to tab them into my boat would be, since his is an aired cored hull and mine a thin (hunter) solid laminate. Why bias tape? Don't most s&g designs call for regular old tape? An idea on the proper layup would ne helpful too...  

Steve W Senior Member

When you use regular 0-90 glass tape only half of the fibers are running across the joint,with double bias tape all of the fibers cross the joint making for a much stronger joint. As Par pointed out how much glass you should use depends on the application,if you are tabbing in a main structural bulkhead such as the ring frame under the mast you would use more glass than a piece of furniture. For some applications just a large fillet will surfice. We do maintainance on a 40ft cold molded race boat that has some bulkheads just filleted in and after 30 years,so far so good. Steve.  

SamSam Senior Member

iceboater said: ↑ I use carriage bolt (photo1) of different size to shape fillets from fiberglass bonding paste (photo 2) from Oldopal. I am not familiar with using expansion foam as filler, I think Gonzo means pre cut foam fillets. For glass over the fillet, I use any ware from 1800-4500 gr/m2 of glass (sorry, metric) tapered out each layer depending on the design. Axel Click to expand...

Another trick for glassing bulkheads with heavier fabrics. We made 30' powerboats AquaMarine Island Hoppers) and I had to tab the bulkheads to the hull. We used Fabmat, which was 24 0z woven roving glued to 1 1/2 oz mat. The 8 & 12" wide strips had to be cut at chines and strakes to conform to the hull and the fabmat was too thick to wet out from one side. So the procedure was to lay it out mat side up on cardboard, wet that out, flip it over and wet out the other side, pick that up, stick it in position and roll out the bubbles. By the time you got a 5' section all wetted out, the mat on one side had begun to dissolve and the WR on the other had begun to un weave itself. With all the cuts to make it conform to the hull shape added in, laminating at all was tough, neatly was not possible. All this was in open hulls in Florida sunshine. After a few boats I started putting the Fabmat in place dry. I would then fold down the vertical halve on the bulkhead, wet out the mat and ply bulkhead and stick it back in place. Then I would fold up the portion on the hull and do the same. Then I would wet out all the WR side and roll out the bubbles. It worked perfectly and 'looked marvelous'.  

Fabmat and stitchmat products are really a waste of resin (lots of it) in an epoxy laminate. In polyester structures a necessity, but not epoxy. The real reason biax and other directional fabrics are better suited to tabbing is simple physics. Conventional cloth is woven, with the fibers going over and under each other. Under load these fibers have to flatten out, which kinks and weakens them, long before the max elongation of the resin or fibers are reached. With directional fabrics (like biax) the fibers lay on top of each other, essentially being continuous straight lengths. Under load these fibers immediately begin to participate in resisting elongation, so the resin and fibers work in concert without delay, kinks or flattening out first. Small taped seam craft can employ regular cloth on their seams because it's more then strong enough to reach the peel strength of the surrounding wood it's bonded to. This is especially true on the outside corners of a taped seam. On larger craft, loads can exceed what cloth can provide, so direction fabrics are necessary. Generally, bulkheads are highly loaded in all but the smallest of boats. The use of biax is the best way, to use the least amount of resin and fabric, to achieve the desired strength and stiffness. Fillets prevent stress risers and hard points, again from simple physical laws. A stress riser is created when you have a sudden and dramatic increase in density along a panel or element. If you have a plywood planking panel and a bulkhead perpendicularly joined to it, loads traveling down this panel reach the bulkhead where there is a sudden and distinct rise in panel stiffness and density. the edge of the bulkhead makes a hard point as the load transmits through it, which can cantilever on the adjoining planking panel. If you can ease this transition area with a ramp, such as produced by a fillet, the load transmission area, is spread out over a much wider area and the density increases more slowly. This helps dissipate the load into the adjoining panel, without a hard point, releasing strain on the joint, the planking panel and the bulkhead. As to your tabbing concerns, two layers of 10 ounce doesn't seem like much. I scale tabbing to the loads anticipated. On a boat the size of yours, it would surely be biax, not cloth. Also if in doubt about the creation or elimination of hard points, error on the too big side with fillets.  

SamSam said: ↑ Another way is to slip the appropriate sized tool socket over your finger and drag that along the filet. A really good tool is a ball bearing welded on a rod. With that you can go into a three way corner (like the inside bottom corner in a box) and all the fillets can be done at once and will match perfectly. Click to expand...

Steve W said: ↑ SamSam, such a tool can be purchased from pattern shop suppliers such as Kindt-Collins or Freeman Supply with different size balls on each end, they are chrome plated and are typically used for working leather or wax fillets into a corner. Actually there are a lot of things used in the pattern making industry you guys may find interesting such as the leather fillets and carvable polyester filler and castable urethanes. Steve. Click to expand...

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PAR said: ↑ Fabmat and stitchmat products are really a waste of resin (lots of it) in an epoxy laminate. In polyester structures a necessity, but not epoxy. Click to expand...

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Bulkhead Compass

• Thread starter Tom P
• Start date Oct 1, 1999
• Hunter Owner Forums
• Smaller Boats

Has anyone installed a bulkhead mounted compass on their H240? Anything to watch out for? How did you make the hole, with a fine sabre saw, maybe a small hacksaw? Help.  

Hole Saw On my 23.5 I used a drill and a hole saw, it makes cutting a perfect circle much easier  

Dave Condon

Compass installation Definitely use a hole saw for a cleaner cut. You will have to cut through the bulkhead and inner liner. Put the compass on the same side as the electrical panel. Run the wires if your compass is lighted to the panel and make sure you hook up to the running lights so the light on the compass is on with the running lights only.To cover up the hole, you can buy cover plates from any marine store but the easy route is to buy a plastic bowl big enough to cover the hole and it will not come out too far into the cabin. One other thing to mention is the lightly scratch the cover and spray paint with a beige paint to closely color match the interior of the boat.Crazy Dave  

Andrew Keddie

Bulkhead Compass Mounting I have put off fitting a bulkhead compass on my 240 for 18 months as I couldn't figure out a neat solution to this:The bulkheads are not set a right angles to the direction of travel of the boat. An angle from the vertical can be fixed with most bulkhead compasses but what do you do about the fixed error introduced by the compass not being at right angles to the centre line of the boat?I thought abound a wood mounting plate to correct the error but it seemed rather ugly and difficult to get just right. Any ideas?  

Michael Bell

Wedge'e I think a teak wood wedge cut to the outside diameter of the compass flange would look OK.  

Contest 101 As far as the bulkhead angle is concerned, maybe a correction chart?I have a Platismo Contest 101 bulkhead compass mounted on my 240.It's nice, and you can also read it, (180 out), in the cabin.Tom  

Its Done I mounted a Saturn compass with an edge card and it looks great and is accurate enough for me. Fortunately, I live in St. Pete (FL) where the deviation is practically 0 already. Using a separate hand held compass, the Saturn appeared right-on. The mounting angle abeam has turned out to be negligable. I haven't even thought about the adjustments that could be done. Please also bear in mind that my primary need is to allow my wife to sail (by keeping us on coarse) while I relax or roam around elsewhere. I will also add, THAT WAS ONE EXPENSIVE 4" HOLE ($30.00 FOR THE "ONE USE IN A LIFETIME" BIT)!  

John Thomas

A bit to sell Any interest in selling that bit?  

Sorry, no bit sale I decided to give it away to my neighbor (the builder). He didn't have a 4" but did have every other smaller size including a 1-1/8" incher I'll need to borrow to install an exterior electrical socket. Sorry.  

Wanderer138

Do it without cutting a big hole My H23 came from the previous owner with the compass mounted to the bulkhead on a gimballed aluminum bracket. There were only four small holes in the bulkhead, three for the bracket and one for the power supply to the internal light. I believe the bracket came with the compass.The compass is easily removed from the bracket for stowing below when not in use, and it takes about 30 secs. to re-install. I really like this setup because the compass is not exposed to the sun and potential thieves when I am away from the boat. I also like the fact that the small holes in the bulkhead are not likely to leak like a big hole and if they ever do, resealing them will not be a major hassle. If only my chainplates were the same way.Peter "Why cut holes in a nice dry boat?" Suahs/v Raven  

Marcie Robson

compass bracket We have a 25 and the compass is on a bracket I have been on larger boats and they were on brackets also. I have always liked the security of being able to remove it when we leave and its kept out of the weather (I wonder if it can freeze??). In a public marina down from us there was some vandalism and some compasses were shattered and others stolen. I figure "out of sight out of mind". With the bracket you dont have to worry about the angle either. If you do decide to drill a big hole use a hole saw and apply masking tape to exposed surfaces being drilled through, this helps prevent splintering and scuffing if you goof. Drill from the outside in to the inside, the side you start on usually looks better. Make sure you dont lay into it or when you break through youll smash the drill into the side of the boat and splinter the other side. Decide which angle the hole should be and keep it that way either paralell with the deck or perpendicular with the surface to be cut if you make the wrong cut youll have to widen the top of the hole and have a gap at the bottom depending on the thickness, Rember to wear a dust mask and clean up, fiberglass dust is as bad as asbestos. I havent drilled or cut into a boat yet but I have installed equipment and found these a few things to remember...hope this helps...Marcie  

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Building Tall Ship Models by the Plank on Bulkhead Method

Posted by Capt Jim on 2nd Apr 2020

Many steps are required to build our high quality wooden ship models.

Most all of our Tall Ship, America's Cup Sailboat, Ocean Liner & Cruise Ship, Runabout Speed Boat, Motor Yacht, Fishing Boat, Ferry & Passenger Boat, Row Boat and Pirate Ship models are built by the plank on bulkhead (or frame) method (joining multiple small pieces of wood like Cedar, Rosewood, Mahogany, Teak and other exotic tropical wood together on the hull). The task requires skillful craftsmen hundreds of hours to accomplish. Below is the step by step process of building a tall ship model.

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As a final building step for most models and especially for Exclusive Edition Model Tall Ships , each model is uniquely identified by a serial number, which is laser cut to the hull of each model. In these editions, we are able to identify the production date of a model, the material that was used on the model, the craftsmen who worked on each area of the model, the individual who inspected the model and also the professional packaging staff. Quality is our number 1 priority, thus all steps are thoroughly supervised from the beginning to the end of making each model. Included with your model is a certificate of authenticity signed by the master builder. Finished models are securely packed with foam sheets, peanuts or bubble wraps. Most of the items are shipped double boxes. All tall ships expert level are fully assembled and packed in an extremely secure wooden crate which is boxed and sometimes double box. Freight shipments are strapped to wooden pallets. Our customer's are usually very impressed with the packaging. One customer of the above San Felipe 37" tall ship model told me about how the shipping carrier was walking up the sidewalk with the boxed crate in his hands when it slipped and dropped onto it's end on the concrete sidewalk, he was amazed that there was zero damage. To view the entire collection of tall ship models please visit our category Model Tall Ships . Please come aboard captjimscargo.com to view a huge selection of nautical decor, nautical furniture, fully assembled model ships, sailboats, speed boats, airplanes and much much more!

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