Designing and building my own kayak has been a project I have wanted to do for a very long time. I probably could have simply purchased plans online, but I enjoyed the challenge of designing my own and I learned a lot along the way. Besides, there is nothing out there that will look like my kayak when it is done. Stitch and Glue kayaks have traditionally looked more blocky and cheap next their Cedar Strip counterparts. but they are generally easier to build.
I want to combine the beauty of cedar strip with the straight forward simplicity of stitch and glue. I decided to build a ‘proof’ model to make sure the geometry is correct and allow for changes to a full scale version by thinking through the fabrication. A friend let me use his laser to cut out all of the pieces for the model. This model is 4 to 1 scale, This means that 3 layers of 1/16” cardboard represents 3/4” Plywood and uses the actual CNC cut files for the full sized version.
Even though many of these parts could have been cut out without puzzle piecing, I chose to cut the geometry as if it was nested on actual 4’X8’ sheets of plywood. The buck will provide support for the hull as well as the strips that will shape the deck. For the model, I chose to use Cherry and Mahogany veneer. The cherry closely mimics the look of the Okoume Marine Grade plywood traditionally used for Stitch and Glue boats.
I chose to build a scale model of my kayak design so that I can verify the geometry and make any necessary changes. The blue tape serves as a backer for the glue. I am using thin CA glue and accelerant to join these pieces together. I wanted the glue to be absorbed into the grain and create a strong bond. In a full sized Kayak, this would be done with epoxy and fiberglass.
The hull is symmetrical, so the pieces can be aligned back to back, taped together, and unfolded into the intended shape. The tick marks are there to help me align the pieces, but also to indicate locations for the stitches in the full scale kayak. Once assembled, the hull can be opened up and placed on the buck. I am using tape to manage the seams. A good rule during the assembly of this model was to only glue when pieces are positioned perfectly. I am applying glue at each one of the tick marks. A lot of time was spent managing the seams and nothing was glued until the position was perfect. I chose to build a scale model of my kayak design so that I can verify the geometry and make any necessary changes. Once these seams are tacked, the tape can be removed and the seams can be glued continuously on the outside and inside of the hull.
Now that the hull is rigid, I can flip the buck over and begin work in the deck. I am temporarily attaching the outside deck strips to the buck with hot glue. Just enough glue to hold the position, but allow the deck to be removed later on. My design uses a center spine to locate the smart strips that make up the deck. The blue tape serves as a backer for the glue. Lining up the hash marks ensures the model I build will be as close as possible to the one I designed in the computer. Even though the deck strips appear to have a consistent width, they do not. Embedded in every strip is information about the surface and each strip is subtlety contoured to produce the gentle curvature of the kayak. These pins will insure a consistent spacing of the strips. These compensate for the kerf of the laser and would not be used on a full scale kayak.
The spacing also nicely accentuates the pattern on the deck of the kayak. Once the deck strips are properly spaced, I can tack them in place every 1/2” or so to lock in the shape. With the initial tacks done, I can remove the tape and fill more of the gaps with CA glue. Being careful not to glue the deck to the buck underneath. Many hobby pen builders finish their pens with CA glue, so I went ahead and coated the entire deck with thin CA glue glue for consistency of finish for the next steps.
Using a razor blade, I scrape off most of the excess coating. Then the surface was sanded with various grits being very careful not to sand through the veneer. Once I had the surface where I wanted it, I applied another coat CA glue. This will be the protective finish until the final gloss coat. Now that the basic shape of the deck is complete, I need to cut out the holes in the deck for the cock pit and storage areas. I printed scaled drawings of the Kayak so I could reference the location of the jigs for the openings in the deck. On the right is a standard coping saw blade, I am using the tiny twisted blade on the left. Here is a quarter for scale. The twisted blade allows you to cut in any direction without repositioning the saw. You simply change the direction of pressure. This blade is actually smaller that the kerf left by the laser! Because the saw cuts in every direction it is important to pay attention. If your mind wanders, so will your cut! I will be keeping these pieces to serve as the hatch covers.
I put a link in the description for every tool I used in this project including the coping saw and blades. This was probably the most nerve racking part of the entire build as the cut needed to be precise and there were no do-overs. I am intentionally cutting the cockpit opening small as I will need to fit it to the coaming base. These rings will provide support for the hatch covers. To fit the coaming base, I would just shave a bit and test the fit.
Once it fit perfect, I could glue it into place. I boiled some water to form the laser cut strip for the coaming. I only needed the shape to be close as it would be glued in place. This was then left over night to dry. Once the piece had dried to shape, I could glue it to the coaming ring.
As you can see… this was a perfect fit to the base of the coaming. I took this opportunity to strengthen all of the seams on the deck with thick CA glue. Structural bulkheads are glued into the hull to support the deck and to provide watertight compartments. I applied a couple coats of Satin wipe on polyurethane to the inside of the hull and to the underside of the deck. The satin finish will contrast with the gloss finish of the outside of the kayak. This piece will provide additional area for me to glue the very tips of the kayak that are inaccessible once the deck is in place. This will provide surface area for glue, but also provide additional structure where it is needed most.
These tabs pull the hull into position so I can tack the seams with CA glue. Once the seam was tacked, the tape could be removed and the seam could be glued inside and outside. Once again, tacking the seam when it is in position and coming back to fill the seam later. Once this seam was complete I could sand the entire model and give it a final coat of gloss polyurethane! (Music) In order to mount the model on my wall, I came up with a 3D printed stand off.
It uses magnets so I wouldn’t need to damage the model. As a proof model, I think it turned out really great! I have some ideas about the deck rigging, but that will have to wait for a full scale Kayak..