Building a Cedar Strip Kayak: The Basics
I've spent many hours canoe camping and fishing. Sometimes I like to get on the water by myself and sometimes a canoe will suit me just fine. Other times the weather is not suitable for a canoe, too windy, too wavy or I just want to cruise the waterways a little more efficiently. A kayak can handle a bit of rough water and can cruise along at speeds comparable to a tandem canoe with two paddlers.
I decided to build a cedar strip kayak. My first choice was a Bear Mountain design called a Resolute. It is designed for larger paddlers and is very stable and has lots of cargo space. Being a smaller paddler I still decided to build this design because I wanted to do some kayak camping and load it up with gear enough for a one week adventure. I built this kayak and took it on a one week camping/paddling trip in Canada's Quetico Provincial Park as well as taking in on several day trips in recent years. It is enjoyable to paddle and handles small wave just fine. The weight was not too bad and is comparable to non-ultra-light commercial designs. It weighs in at about 60 lbs, 16ft. 3in, with a 25.5 in wide hull.
Recently I decided that it would be nice to have another kayak, perhaps a little slimmer, a little lighter and little faster. I decided to build the Bear Mountain Endeavour design. It has a length of 17ft. and width of 23.5 in. The construction of this kayak is described here.
An alternative to strip construction is using plywood panels and stitch and glue construction. The boats constructed using this method seem to be somewhat lighter in weight but I believe this method is more difficult to use when building from scratch. It is more likely better suited for a kit where the panel come pre-cut to the proper dimensions. I also believe the time required to build a complete boat is less. Strip construction gives more opportunity to customize the look of your boat with colors and patterns in the strips.
Generally a longer, narrow kayak will be faster but less stable and carries less gear if you plan to use it for overnight trips. If you want a sea kayak, you should look for a design that has a hull which is between 15 and 18 feet long. Be prepared to answer lots of questions about your hand built cedar strip kayak and get lots of looks and complements from people you encounter on your paddling adventure.
As before when I built my other boats, I read and re-read Ted Moores book "Kayak Craft". Instructions in this book are very thorough and I would recommend reading before you begin a project like this. I also read "The Strip-Built Sea Kayak: Three Rugged, Beautiful Boats You Can Build" by Nick Schade. I followed Ted's method because it seemed more straight forward, however the sleek designs in Nicks book are attractive.
plans - lofting
You can purchase plans from a few different sources or you can create your own from tables in the books I mentioned using a process called lofting. With this process you use the dimensions in the table to create outlines of the forms, which are cross sections of the hull at regular (typ. 12") intervals. I drew the shapes by hand onto a a couple of pieces of brown craft paper. If you are more technical you could use CAD software and a plotter to print the large drawings. I only created half hull outlines because it is symmetrical about a vertical axis. This process is time consuming but can save you some money.
building a platform
You need a platform or long table on which to build your kayak. I built one 12 in wide by 16 ft long from 1 sheet of 3/4 particle board, leaving only a small piece of scrap. I set the table on a pair a saw horses and attached it to them with pieces of scrap wood. I also added some bracing and legs in the center to provide more support. The table needs to be level and flat.
cutting the forms
I transferred the 1/2 hull plan outlines to poster board to make full size templates which I traced onto particle board to make the forms. Actually in this case I had a mixture of scrap wood from an old desk and other discarded furniture that I disassembled. The forms were then cut out slightly over sized using a jig saw and their edges were smoothed and trim to the outline using a drum sanding bit in my drill press.
Cover form edges
The strips will be glued along their edges and stapled to the forms. Some protection on the forms is needed to keep dripping glue from permanently sticking the hull to the forms. Edges of all the forms should be covered including the stem molds. Plastic packaging tape works well for this.
attaching the forms
The forms are then attached to the table on 2X2 station blocks screwed to the table, one every 12 inches. They are attached with screws, using extensions on the deck side of the forms, which holds the forms a few inches above the table. I made the extensions from 3/4 inch thick scrap wood. Once all the forms are set, they need to be checked and adjusted so their centerlines are lined up. They also may need to be adjusted so that if a strip of wood is laid across them there are not gaps or high spots. The strip should touch all the form edges over the entire shape of the hull
milling the strips
I cut my own strips from cedar purchased at Home Depot. On my first kayak I used some salvaged white pine that was about 130 years old and had very straight grain. Some of the strips are cut from 5/4 cedar deck planking but it makes strips a little wide for the my liking.
Use the table saw with feather boards clamped to the guide and table to keep the strip thickness uniform. A circular saw with a guide jig for cutting the strips can be used. Make a few test cuts and adjust your set up. Using a thin kerf blade like the Diablo, cut more than enough strips since some will break or have large knots or other problems. They do not need to be the total length of the boat, they can be scarf jointed or butt jointed on the hull. The strength of the hull comes from the wood core laminated with fiberglass not from using continuous strips. Measure the circumference of the widest from and divide that number by 1/2 inch to estimate the number of full length strips you will need. Once all the strips are cut use a router table with a ¼” bead and cove bit to mill the edges. Cut the bead first since the cove is more delicate. Once again make some test runs to adjust your set up. Cut shorter strips of softwood and hard wood to laminate for the stems.
It is difficult to get perfect strips due warping feeding difficulties. If I build another boat I will first purchase a thickness planer and cut the strips extra thick on the table saw then use the planer to make them a uniform thickness.
laminate the stems
The strips used for the stems need to be steamed and clamped onto the stem forms then allowed to dry before gluing them together. Typically 3 or 4 strips are used for each inner and outer stem. I used a 6 foot piece of PVC drain pipe plugged at each end with a piece of wood. One end had a large hole drilled in it. An old percolator style coffee pot on a camp stove was used to create the steam. A short piece of copper pipe replaced the glass bubbler on the coffee pot. The PVC pipe was hung above the stove. The secret to good bending is HOT steam. Use epoxy thickened with sanding dust for glue. When gluing the stem strips together do not glue the inner stem to the outer stem.
attach the stems
Once the glue for the inner stems has firmly set up, they can be attached to the stem mold with a screw through the last hull form into the end of the stem and a screw through the other end of the stem into the stem from.
The stems need to be trimmed with a plane so that the ends of the planks rest flat against them. This provides a solid surface for the glue joint.
attaching the sheer clamp
The sheer clamp is a piece of wood about 3/4" X 7/8" that runs the length of the kayak on each side. It is used to hold the bottom half of the hull to the deck. I made mine from yellow pine by ripping 2X4s but it can be made from cedar or even hardwood. It is attached with screws to notches in the forms. The screws run vertically up into the forms to hold it on while applying strips to the lower hull. It should be covered with plastic packing tape to keep it from becoming glued to the hull. That will come later. The sheer clamp needs to be cut at an angle on the ends so that it will come together and butt uniformly against the stem on each end. A notch in the bow and stern forms needs to be cut in order to accomplish this.
stripping the hull
Now comes the fun part. Start attaching strips to the forms at the part of the form closest to the strong back and work towards the center of the hull. Attach with cove side up to hold a bead of glue. Glue and staple the ends of the strip to the stems, allowing the strip to run past the stem a little. Press the bead of next strip firmly into the cove of the previous strip and staple through both strips into the form. About 3 or 4 strips per side can be attached. Let the glue set before attaching more. Where the strips seem to pull apart between the forms, masking tape can be used to hold them together. You may have to use some creative clamping methods to hold the strips in place, especially where the round the curves in the hull. Once the hull is stripped up to the flatter bottom section the strips will have to cut and fitted neatly together.
attaching outer stems
Once the hull is completely stripped it is time to trim the strips flush with the bow and stern stems. The outer stem is then mortised into the hull bottom and glued to the inner stem with thickened epoxy. Screws coated with wax are use to hold the outer stem in place. They will be removed when the glue sets and the holes will be plugged.
The outer stem should be planed and sanded until it flush with the strips in the hull,
plane & sand
Remove all the staples. The joint where strips meet at curves in the hull are a little squared off. These joints need to be planed to make the hull smooth. The hull can then be sanded with coarse, medium and then fine sandpaper to achieve a smooth or “fair” hull. The Random Orbital Sander works well for this step. Sanding seems like an endless activity, you will finally get to a point where you say “Well, I think that is good enough”. Before the final sanding, the hull should be wetted down and allowed to dry to raise the wood grain.
exterior fiberglass the lower hull
Fiberglass cloth is laid over the hull so that it extends just past the stems, then smoothed with a soft bristle brush. I used 6 oz. e-glass for this step. Epoxy resin and hardener is then applied to the cloth in small batches, working from side to side, in about 2 to 3 foot long sections. It is important that the temperature of the workshop is warm enough as that will affect the curing time and the rate of flow. Three coatings of resin/hardener are applied, the first to wet out the cloth and soak into the wood hull, the second to fill the weave of the cloth, the third to finish and protect the cloth. Each coating, except the third, should carefully squeegeed with a plastic scraper and only applied once the previous coat has become tacky. This step is intimidating but not real difficult if you are careful. Proper mixing of the resin and hardener are very important.
stripping the deck
Once the epoxy on the hull has cured the screws holding the mold extensions to the station blocks need to be removed and hull is then flipped. I first lifted it off the build table and set it on the floor. Next two plywood cradles were made and screwed to the station blocks to hold the hull while the deck is being stripped. First two strips on each side are laid then clamped and glued to the sheer clamp. Then one strip is placed down the center and attached temporarily to the forms with small finishing nails. The remainder of the strips are placed from the center strip towards the outer edges. Once this is complete, plane and sand as usual. On the deck I did not use staples. Instead I held the strips in place with L shaped scraps of wood which were clamed to the forms with C-clamps. Masking tape helps a lot too.
exterior fiberglass the deck
The same process is followed as with the lower hull. I used 4 oz. e-glass for this. Once the epoxy has cured the excess can be cut off with a utility knife.
interior fiberglass the lower hull
Fiberglass cloth is laid inside the hull and held in place with clothes pins, then smoothed with a soft bristle brush. I used 4 oz. s-glass for this. The cloth is just short of the inside stems. Epoxy is applied the same as was done on the exterior. Any runs on either side of the hull can be taken down with a paint scraper once the epoxy has firmed up sufficiently. I also laid 6 in wide strips of fiberglass cloth across the floor of the hull about 6 inches apart. They did not span the entire width, but ended just after the hull curves upward. These strips were applied after the first coat of epoxy. The second and final coat was applied over both the base layer of cloth and the added strips.
interior fiberglass the deck
Before this step can be completed the sheer camp should be shaped with a hand plane and sandpaper to round off the interior edge. Then a filet of epoxy mixed with sanding dust is applied between the sheer clamp and the deck so that the fiberglass cloth with form over the sheer clamp. It is not covered with fiberglass however on the outside edge where it will eventually be glued and screwed to the lower hull. As in previous steps the cloth is laid and smoothed with a brush. I used 4 oz. e-glass for this step and 2 coats of epoxy.
Now is time to cut hole in the beautiful deck. I cut an egg shaped hole for the cockpit that was about 29 inches long and about 18 inches wide. I found an diagram of a shape online and enlarged it then printed it out on 8-1/2 X 11 sheets then piece them together. This was traced on poster board then taped to the hull so its center was just aft of the center of the boat. I also looked at the plans in Kayak Craft to help judge where the cockpit should be placed. Once the outline was traced on the deck I started the cut with a utility knife and finished with a jig saw. I used three layers of 1/4 inch exterior plywood for the spacing between the deck and the cock pit lip. the spacer s were each cut into two pieces running vertically then glued and clamped to the deck around the cockpit opening. I used a few brass screw running from the underside for good measure. The lip was made from 1/4" X 4" poplar, which was cut into 4 sections to make a lip that extended past the spacers by about 3/8" . This was also glued and clamped on to the spacers. Once all the glue is dried the edges are rounded and sanded. I used a wide piece of basket weaving stripping or reed, which I think is ash I think, to cover the exposed plywood on the inside of the cockpit. It was glued and held in place with masking tape. After the final sanding of the cockpit spacers and lip it was covered with 4oz fiber glass on the inside and out. The outside can be a little challenging.
I cut more holes in the deck the same way as the cockpit hole was cut, one for the rear hatch and one for the forward hatch. The rear hatch was placed about 12 inches behind the cockpit. It was made in sort of a hexagon shape. The forward hatch must be place forward of your foot braces. I sat on the floor and with my back against a wall and measured the distance to the bottom of my feet then added half the length of the foot brace brackets then about 2 inches. This is where I placed the near edge of the forward hatch. It was more of a rectangular shape. The pieces I cut out were wrapped in plastic and taped back in place then the deck was flipped over to make the hatch cover lips. I laid 2 layers of 4 oz. fiberglass cloth, followed by one layer of 5 oz. carbon fiber cloth, then a layer of 6 oz. and a layer of 4 oz. fiberglass cloth. All layers were soaked with epoxy. Once the epoxy has hardened, the lids are removed and the rigid cloth was then cut out leaving a 3/4 inch lip remaining. I added a half donut shaped handle to each cover. The hatch lips were covered with 1/4" X 3/4" neoprene weather stripping in the final finishing step.
Foot braces are pedals on the inside walls of the kayak and help add stability when paddling. You can make your own adjustable set if you are clever, but I purchase mine from Wal-Mart online for about $20. The foot brace bracets were attached using glue on studs, which are just 1/4-20 studs with a perforated flat plate for a head. The studs were glued with thickened epoxy and clamped to the side walls about 3 inches down from the top edge of the lower hull and leveled by eye using a strip. After the epoxy setup 2 layers of about a 3 inch square (or round) patch of fiberglass cloth was epoxied over the head of each stud to give added support. The brackets were then attached.
A foam bulkhead is placed just behind the cockpit and just behind the forward hatch. It is best to use at least 3 inch closed cell foam. I tried to make my own by laminatining piece of a camping sleeping mat to polystyrene foam, resulting in 2 inch thick bulkheads. I used exterior grade silicone calking to glue the pieces together. the shape was traced from the nearest larger form. I used the same caulking to attach the bulkheads. they are first attached to the lower hull, the silicone will be applied to the top of the bulk head that meets the deck when the deck is attached. I also added a fillet of silicone, using my finger to shape it, around the edges of the bulkheads.
attaching the deck
The lower hull should already have screw holes where it was attached to the sheer clamp earlier. I used a countersink bit on each of these so a flat head screw would fit flush. First I applied silicone to the top of the bulkheads. Next I applied thickened epoxy to the outside edge of the sheer clamp on the deck. After setting the deck onto the lower hull, I used 3/4" #8 brass flat head screws to attach the deck. I pressed the deck down tightly against the hull before attaching each screw. I cleaned off any glue that oozed out then clamped the deck to the lower hull using ratchet straps, bungii cords, rope, etc. anywhere I saw that the lower hull was not tight against the sheer clamp.
The joint where the deck meets the lower hull should be covered to help keep it watertight and also to cover the screw heads. I used a 3/8" thick by 3/4" wide strip of poplar which was two 10 foot lengths scarf joined together. It would be better to use a strip that is 7/8" or even 1" wide. Mine barely covers the screw heads. This trim piece is attached with thickened epoxy and #6 1 inch flat head brass wood screws. Before I attached it I filled any voids in the hull to deck joint. The screws were spaced evenly and between the screws holding the lower hull and deck together. They were also recess about 1/8" and covered with a piece of dowel rod which was glued in place with Titebond III. I could have use thickened epoxy but I ran out. Next the dowels were cut flush and the trim piece had its edges rounded and it was sanded.
The epoxy is sensitive to UV light and too much exposure can make it break down. It must be covered with spar urethane varnish which contains UV blockers. I used one quart of System 3 Marine Spar Varnish. This allowed me to apply 3 coats with the first being thinned with mineral spirits. Next I applied a coat of Helmsman Spar Urethane. These first 4 coats were applied with a brush followed by a coat of Helmsman spray spar urethane. The varnish should be allowed about 7 days to harden before the boat is paddled.
deck rigging and hatch covers
The lips on each hatch were lined with neoprene weather stripping and the hatches are held in place with black 3/16" shock cord wound between stainless steel hammock hooks on each side of the hatch. I also added some shock cord in front of the cockpit to hold temporary items like a raincoat, water bottle, etc.
- Building a Cedar Strip Canoe: The Basics
A practical account of my experiences and a brief guide to building a cedar strip canoe. It includes links to stories of using the canoe for wilderness camping and fishing.