Kayak Building Notes
by Nick Schade

An updated copy of these notes is included with each set of Guillemot Kayaks plans.

These building notes are not intended to tell you everything you need to know to build a kayak. Instead they are a supplement to my book — The Strip-Built Sea Kayak. If you do not already have my book, I suggest getting it, it is a complete instruction manual for building any of my sea kayak designs. It is available through me, or through any bookstore. If you have any questions, feel free to email me at Email Nick Schade or call (860) 659-8847. Be sure to look at my web site at www.guillemot-kayaks.com the latest techniques and ideas

Don’t Over-Sand

People complain about the amount of sanding required to make a stripper. A really good finish does require a fair degree of sanding. However, there are some things you can do to minimize the amount of sanding. The first step is to do much of your fairing with a plane or spoke shave. Use one of these tools to remove the angles created by joints between the strips. Next use a fairing sander or "long board" to grind down the high spots.

Fairing is a whole-boat operation. Don’t concentrate on one spot. This can cause low spots which is the opposite of what you are trying to accomplish. If there is blemish that needs deep sanding, either fill it in if it is small, or gradually fair the surrounding area down to until the blemish is ground out. The best tool for this may be a plane then go over the region with the fairing sander. Use a course grade of sandpaper on the fairing sander, 50 or 60 grit is reasonable. Make sure you move the fairing sander parallel to strips. This will minimize the number of scratches that will show up later. Any cross-grain scratches will show up when you apply the epoxy.

Run your hand over the boat, your hand is very sensitive at detecting non-fair spots. You will feel a hump or hollow. Use a plane to knock of the tops of high spots. When you are done fairing, any saw marks in the wood should be removed. If there are any gaps between strips, now is the time to fill them.

Now with 80-grit sandpaper, sand the whole boat. Again, don’t concentrate on one spot. Move the sander in 2’ long sweeps over the boat. Work the sander parallel to the centerline and move from centerline to sheerline, overlapping your strokes as you go. When you have completed one 2’ wide region, move 1’ down the boat and repeat the process, so that you are overlapping onto previously sanded wood. Move the sander rapidly and smoothly. The goal of this sanding is to remove any scratches left over from the fairing. When the surface looks uniform, vacuum the surface and use a wet rag to swell any compressed wood.

After the wood has thoroughly dried, sand it again with 80-grit sandpaper. In most cases this should be all the sanding you need. You do not want a super smooth, polished surface. Instead you want a surface free of visible scratches but rough enough for the epoxy to get a good mechanical bond. If you sand to 220 grit as you would on a piece of furniture prior to varnish, you risk having a weak bond between the wood and the fiberglass.

Planing

Successful planing is not hard, but it does take a little practice. The most common problem is "tearing". Usually this will happen when planing against the grain. The first solution is to reverse the direction you are planing. However, this is not always an option. You should be able to plane in either direction without tearing. Tearing is usually caused by one of two problems; either your blade is not sharp enough or it is set too deep. Start by sharpening. Then back the blade all the way in and start pushing the blade out one quarter of a turn the adjustment screw. Try planing after each turn. At first nothing will happen, but as you get it farther out, the blade will start to bite into the wood. At first it should create very fine shavings, another quarter to half turn of the adjustment knob should work fine. If you have an adjustable throat block plane, close down the throat so there is just enough room to let the shavings to pass through. Too tight and the shavings will get stuck and too wide the wood will have room to lift before being cut off and thus can tear.

Even once the blade is sharp and it is adjusted well, you may still get some tearing. The next thing to do is change how you push the plane. Do not hold the plane parallel to the direction you are pushing it. Instead, hold it an angle to the direction of motion. This causes the blade slice through the wood more gradually than if you push the plane straight.


Holding the plane at an angle to the direction of motion will make it cut better

On the worst grain you may still get some tear out. In these places, you will just have to do more sanding. Although sanding is not as effective for fairing, it does not have any problems with squirrely grain.

Recessed Cockpit

In The Strip-Built Kayak, I talk about doing a "recessed cockpit". This involves cutting a hole larger than the cockpit, restripping horizontally in the hole and then cutting out the cockpit sized hole. I mentioned this as an optional operation for the all the designs, but only gave it as a standard on the Guillemot. As I have built more boats of different styles, I have come to like the recess even more. It originated as a primarily aesthetic idea. I thought it would look cool. As I’ve built more, I’ve come to see that it has some very utilitarian functions. The recess lowers the height of the coaming, permitting a more comfortable paddle stroke; it creates a flat spot for your knees for more comfortable bracing, and most importantly, it makes the coaming easier to form.

The recess at the front and back of the cockpit reduces the curvature of the coaming. This makes wrapping the coaming lip laminations much easier because they don’t need to bend in as many directions at once.

The most effect on the curvature occurs right at the front and back of the cockpit. The simplest for of the recess is just a triangle cut out at the front and back of the cockpit. If you mark a point 2 to 4 inches in front of the standard cockpit front and then draw a straight line back to hit the cockpit pattern at a tangent you will create a simple recess pattern.

Cut out the cockpit with the recess triangle, then fill the triangle with horizontal strips and cut the standard cockpit shape. A deeper recess can be made by cutting a larger first hole.

Kayak Thigh Braces - Strip recessed area, Cutout cockpit shape, Start stripping the vertical section, Glue strips on top of thigh-brace area, Apply Fillet on both sides of the vertical strips.

Figure 1 Integral thigh braces can be incorporated into the recessed deck area.

 

Kayak Thigh Braces

In order to really be comfortable in a kayak, it helps to fit securely. A firm object to push against is less tiring that having your legs loose in the boat. But then again, it is nice to be able to move around and get in and out easily. A secure fit and room to move can be mutually exclusive properties. Having a place to brace your knees and thighs usually requires a small cockpit that may be hard to get into. One solution is thigh braces. These are a part of the cockpit coaming that sticks into the cockpit opening giving something for your legs and knees to brace against.

I incorporated thigh braces into my Night Heron. It is doesn’t take any extra material and is not very hard. The thigh-braces cut into the room in the cockpit, but leave space where you need it. I can still lift my knees out of the boat by bringing them up between the braces one at a time. I built the recessed deck as described in my book, making sure I had long strips in the region I wanted the thigh-braces. When I cut out the hole for the cockpit, instead of just following around the "oval" of the cockpit, I left part of the recess-deck sticking into the cockpit area on either side of the front.

I started putting on the vertical part of the coaming in the regular way, gluing strips in vertically starting at the front. As I got back to the thigh brace, I just tacked the strips directly on top of the recess-deck, continuing backwards while following the line of the cockpit. You don’t need to do a good job gluing here because it will all get glued together with epoxy later. When I got back to the section where the hole followed the cockpit line again, I went back to gluing the strips to the edge of the hole. Where the strips transitioned from being glued on the side-of-hole to the top-of-the-deck, I needed to sand away the corner of the vertical strip slightly for a close fit. I used hot-melt glue throughout.

When the vertical part of the coaming is completely installed, clean off the squeezed out glue and sand the inside and outside. The outside is indistinguishable from a normal cockpit. Put a fillet in the corner and fiberglass normally. The inside will need a fillet where the thigh-brace meets the coaming. Fill up any gaps with epoxy/sanding-dust putty and apply fiberglass over everything. Attaching the coaming lip is no different than if you didn’t have the thigh-brace. Sand everything smooth and you are all set. You can put foam padding on the thigh braces as needed.

I have found the Expedition Single usually doesn’t need thigh-braces because the contour of the recessed deck provides enough room to brace. Some people may find them beneficial in the Guillemot and the Great Auk.

Making Strips More Flexible

The easiest way to make a strip more flexible is to make it narrower. This works great if you are trying to bend the strip side-to-side such as the sheer-strip. However, sometimes you need to bend the strip up-and-down or across the 1/4" thickness dimension. If you don’t want to make your strips any thinner, you need some other solution. With my designs the deck can sweep up a lot at the ends. It can be difficult to get the strips to conform to this curve. There is a way to make the strips thinner without actually using thinner strips. You can use a razor saw or Japanese pull-saw to rip the end of strip into two 1/8" layers.

Taper the end of the strip in the usual way so it will fit into the space, even if it has trouble bending up. Then lay the strip flat on a worktable and with your saw held horizontally cut into the tapered end of the strip to make two equal thickness layers. Since the highly curved section of my designs does not usually last very long you only need to split the last few inches.

If you now try bending the end you will see the two layers slide apart slightly, letting the end bend fairly easily. Inject a little glue in between the two layers and install the strip normally.

Sealing the Inside

The inside of a kayak does not need to be finished as finely as a boat like a canoe because the inside is not generally visible. However, water does get inside and it can potentially soak in through the epoxy and fiberglass if there are any pinholes in the finish. A single coat of epoxy and fiberglass can have small holes, particularly anywhere there is a pocket to absorb the epoxy, such as staple holes and joints between strips. You could solve this problem by doing a fill coat on the inside in the same way you do the outside. But this could add quite a bit of weight. Instead, you can apply a couple coats of thinned varnish or rub epoxy onto the surface. If you paint on a thin coat of epoxy and rub it around with a rag, you will force resin into pinholes and remove excess.

As a further prevention, you should always empty out your boat before putting it away in storage. Sponge out any standing water and keep the hatches open so the interior can dry out.

For UV protection, you should varnish any part of the inside that will get sun exposure.

The End Pour

The end pour should be as small as possible to keep the weight low, but you want it big enough to install a grab loop and strong enough to secure the hull and deck together. The ends of the boats are pretty small, so a little goes a long way when you pour something in. Usually about a 1/2-cup of epoxy with enough q-cell or -balloons to make it the consistency of thin mayonnaise will be enough. Add filler to the epoxy to make it as thick as you can with it still able to flow.

The solid mass of epoxy in the end can heat up quite a bit. You don’t want it to get so hot it damages the boat. If the air temperature is below about 75°, this is probably not a problem. Above that you should probably put the end of the boat in a bucket of warm to hot water. This moderates the temperature even if the water is hotter than the air because the water acts as a big heat sink. While the epoxy may get quite hot, the boat won’t get much warmer than the water.

If the air temperature is really cold, it may take forever for the epoxy to set up. Again placing the end of the boat in hot water to help along the chemical reaction of the epoxy.

Note that you do not want water to get to the uncured epoxy. You will probably want to tape the exterior seam and making sure it is sealed before placing the boat in the bucket. You may also wrap the end in a plastic bag to keep it dry, but be careful that you don’t rip the bag. Use a heavy-duty bag.

Building Without Staples

There are several methods that have been suggested for eliminating staple holes. The first methods involve filling in the holes after you make them. Some people have used toothpicks stuck in each hole. This is a tedious task. You don’t want to stick the toothpicks so far in that they go into the staple holes in the forms, because you will in essence be stapling the strips back to the form and you will have trouble getting the boat off. After all that work, the toothpicks don’t look much better than the raw hole because the wood of the toothpick will probably not match the strips. Instead you can fill the hole with putty made of epoxy and sanding dust. You would think that this would match better than the toothpicks, however even if you use dust from the same wood you are filling, the putty will be darker. You need to add something such as Q-spheres that are white to lighten of the putty.

It is easier if you don’t make the holes in the first place. Almost all the methods to do this, that we have heard of require you to install one strip per side then let the glue dry. All the different methods are just different ways of securing the strip in place until the glue is dry enough to install the next strip.

 

Staple free stripping

Figure 2 Stripping without staples requires some sort of clamping method.

U-clamp

A "U" shape plywood fixture with the slot slightly wider than the thickness of the strip can be fitted over the strip next to the form. With the strip pushed into place a spring clamp is used to hold the U-clamp to the form, this securing the strip in place

Elastic strap

A series of nails driven part way into the face of the form can be used as cleats to secure rubber bands. By hooking a rubberband below the sheer and looping it up over the strips and back down to another nail, you can strap down the new strip. Shock-cord, string, or strings of rubber bands tied together may be used as well.

Screw and Dowel

This unique idea requires you build with the cove side exposed. By placing a dowel in the cove, you can use a bugle-head (sheetrock) screw to clamp down against the dowel. Drive the screw as close to the dowel as possible, so the bugle shape of the screw produces a clamping pressure

Spring Clamp

A series of holes or slots cut along the edge of the forms can serve as a place to grab with a spring clamp so you are directly clamping the strip to the forms.

The reason you can only do one strip per side at a time with the above methods, is in each case the clamp goes over the top of the strip and you need to remove the clamp before you can add the next strip. A idea that we have heard suggested is to hot-melt glue the strips to the forms. Presumably, since the hot melt glue is not very strong, you can break the bond between the strips and the forms to remove the boat. We would perform some experiments before stripping up the whole boat with this method.

Is all this effort worth it? That depends on a few factors. How fussy are you. Standing 5 feet away from the boat, the staple holes will be hard to see, from 10 feet away nobody will see them. Stapling is by far the quickest and easiest way to get the boat done. If you want to work fast and a few small holes don’t bother you, use staples. But if you are only working about an hour a night, maybe all you can accomplish is one strip per side per night anyway. In that case, it might not take you much longer to use one of the clamping methods. I like to finish the boat and get it in the water. I use staples.

Care and Feeding of Your Finished Kayak

Strip-built kayaks are made of cedar and other lightweight woods encapsulated in a layer of epoxy and fiberglass. The epoxy and fiberglass provide a rugged coating that is impervious to water. Your boat will not require much maintenance, but it is not completely carefree. Epoxy will eventually be degraded by exposure of Ultra-Violet (UV) light. Varnish is applied over the epoxy to protect from UV light from the sun as well as provide a high gloss finish.

Every Day Treatment:

Scratches:

Most scratches will do nothing more than scratch the outer layer of varnish. If the scratch pretty much disappears when you make it wet, it is just a surface scratch. This is not a big deal and does not need immediate attention. Next time you re-varnish the boat these scratches will be fixed.

If you hit a sharp object really hard you may scratch through the varnish, into the epoxy and down to the fiberglass. If when you wet the scratch you see whitish mark you have probably hit the fiberglass. If the white mark is small an intermittent, it is again not a big deal. You should probably paint the scratch with some varnish just to keep water out of the weave of the cloth.

A deep scratch may reach the wood. This would require a pretty major impact. When you wet down the scratch you will seat a large white line or spot. If the wood turns somewhat dark it means water is getting at the wood. If this happens out on the water, put a patch of duct-tape over the spot. When you get back, you should scrape away any loose varnish and epoxy. Apply a coat of epoxy over the cleaned up area then sand it smooth and apply a few coats of varnish.

Really deep scratches where the fiberglass is badly broken and the wood is easily visible will require that you sand away the fiberglass around the damage and apply new fiberglass and epoxy.

Holes:

Dropping the boat on a sharp object or otherwise hitting a sharp object with great force may put a hole in the boat. This may require replacement of wood and re-fiberglassing

Yearly Maintenance:

Exposure to the sun will dull the finish on the varnish and reduce its ability to block UV. The varnish will need to be refinished eventually. This does not need to be yearly, it depends on how much use the boat gets. If you use it every weekend from April through November, you should plan on re-varnishing every year. If you only use it a couple times a month through out the summer, you can probably go several years before varnishing. Look at the varnish at the beginning of each season. If it is still bright and shiny, it is probably OK. If it is dull, plan on applying new varnish. If you have a lot of scratches on the bottom, you may want to give the bottom a new coat even if the deck looks fine.

Prepare the boat for sanding by removing all the deck lines. Wash down the boat with soap and water. Remove the gloss from the varnish by sanding with 220-grit sandpaper. Be careful not to sand too deeply. You do not want to sand into the epoxy. Continue sanding with finer sandpaper, finishing with 320 or 400 grit.

I use Z-Spar Captains varnish. Any good quality spar varnish with UV blockers will work. I find a foam brush to work very well to apply the varnish. High quality natural bristle brushes are said to work better, but they are expensive and difficult to clean. Foam brushes are hard to clean also, but why would you clean them?

Apply two or three coats of varnish, sanding lightly with fine paper between coats.

Approximate Material Requirements

Model

Little Auk

Coastal

Great Auk

Guillemot

Expedition Single

Play

Night Heron

Double

Fast Double

Length (ft)

10

17

17

17

19

17

18

20

26

Max Girth (in)

18

14

17

14

14

14

14

18

14

Surface Area (sq in)

5,675

7,050

8,352

7,100

8,010

6,620

7,344

11,830

12,360

Total Cockpit Perimeter (in)

85

76

85

76

76

76

76

153

153

Glass Width (in)

38

38

38

38

38

38

38

38

38

3/4" Strips (linear ft) + 10% extra

744

928

1,096

936

1,056

872

968

1,552

1,624

1/2" Strips (Linear ft) with extra

50

200

100

200

250

200

200

100

300

Vertical Combing Strips (2" long)

122

109

122

109

109

109

109

218

218

Combing Lip (1/8x1/2 Ash) (ft)

43

38

43

38

38

38

38

76

76

Strong Back Length

9’ 11"

14’ 11"

14’ 11"

14’ 11"

17’ 10"

14’ 11"

13’ 11"

17’ 11

23’ 1"

Foam Bulkheads

0

2

2

2

2

1

2

4

4

38" wide Fiberglass (yds)

13

23

23

23

25

22

23

27

34

Epoxy (gal)

1.5

1.5

1.5

1.5

1.5

1.5

1.5

3.0

3.0

Adjustable Footpegs (pair)

1

1

1

1

1

1

1

2

2

Seat

1

1

1

1

1

1

1

2

2

Shock Cord (yds)

0

5

7

5

10

5

5

14

14

Backrest

1

1

1

1

1

1

1

2

2

Webbing (ft)

5

5

5

5

5

5

5

10

10

 

These material requirements are approximate. If you are a first time builder, you may want to assume that you will use a little more. For example, 1.5 gallons of epoxy is enough to build most solo kayaks, but given waste due to mixing too much, spillage and applying too much resin to the cloth, you may end up using more. If you are cutting your own strips, you will want to get enough material that you can ruin a few strips before you have worked out how best to cut them. Items like the webbing and shock cord will vary depending on exactly how you outfit your boat.

Complete Kits

Kits are available through Newfound Woodworks (603) 744-6872 and Noah’s Marine Supply (416) 232-0522. They both have all the necessary materials and know how much you need to complete your project.

Kayak Building Notes

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