The Folder

It is one of those rights of passage that we all remember...first kiss, birth of a child, first words, walking, and your little girl outgrowing her first SOF. McKinley's most recent growth spurt has made getting into the blue bomber quite a chore. So, of course, it is time for another boat. I have long admired Tom Yost's designs, especially his folding kayaks. When I saw his design for the Sea Pup, a kid's design, I knew I had found the right boat. This Sea Pup is built directly along Tom's specifications with High-Density Polyethylene (HDPE) sections, 3/4" aluminum stringers, and an 18 oz. PVC coated nylon skin. Once complete, the boat will break down into a package less than 48" long. Many thanks to Tom for his design, building techniques, and constant support and advice throughout this project.

	Here are the patterns after lofting, ready for transfer to the HDPE sheet. A 3'x3' sheet of 1/2" HDPE cost me $69.
Here are the sections ready for cut out and drilling.
	Once drilled, cut out and shaped, the sections are mounted to an external strongback. The tubes here are each made up of 4 sections of interconnected 3/4" aluminum tubing (with 5/8" inserts). The tubes snap into the sections. This picture is about 4.5 hours into the build.
Another view of the frame in progress.
	The frame with supporting "inwales" added (on the inside of the sections parallel with the gunwales).
This photo shows the ends of the chines where they will connect with the HDPE stern plate.
	The floor and footboards are cut, but not yet mounted to the support brackets. I decided to put in footboards, because McKinley liked them on the Blue Bomber. The pivoting seat back is also visible.
A closer view of the pivoting seat back. The backrest snaps onto an aluminum and HDPE support bracket and is removable.
	The bow. The keel is bent and the HDPE support is mounted. The deck ridge still needs to be mounted.
The stern. As with the bow, the deck ridge is not yet mounted.
	The beginning of the coaming. This ring will have a 1/4" HDPE lip on top of it and and identical 1/2" plywood base under it. It will all attach to the skin.
The completed frame, ready to move off the strongback and start skinning.
	Another view of the frame.
The hull skin in place and the lacing started. Yes, I know, big surprise on the color.
	A view of the lacing. I am using 45 pound test braided ice fishing line. It is thin enough to go over the deck ridge, so I will be able to remove the skin without cutting it open.
After a quick skin removal to do a few mods suggested by Tom, the skin is back on and the bow and stern are cut and glued.
	The kayak deck-side up and ready to finish the ends and get to work on the deck.
The front two sections of the skin have been attached. The light blue sections in the cockpit area are cut and ready to glue. The aft section still needs to be trimmed. McKinley's ultimate design incudes the addition of colored dots and swirls on the skin.
	After a short break to complete a couple of other projects, I managed to get all of the skin pieces glued and the coaming completed. Here is a shot from the bow looking aft.
The cockpit area. The skin still needs a bit of tightening and the zipper still needs to be added to make this a true "folder".
	Another view of the cockpit area
A shot of the inside. Some of the strings have been cut, but the fumes of the curing glue are still a bit strong to be sticking my head inside to cut the rest.
	Everything but the zipper. The deck rigging is on (except for the stern grab loop, which will go on after the zipper). Everything is ready for the pool launch tomorrow.
Another shot of the full boat.
	The design of the forward deck rigging. The PVC allows a lot of flexibility in design.
The bow grab loop. The face on the other side has fangs.
	A shot from the bow.
One of the toughest things with kid's boats is finding accessories of the appropriate size. The Greenland paddle was custom made and I removed almost 10" from girth of the spray skirt tunnel to make a good fit for McKinley.
	The finishing touch.
The big launch. The kayak fit her very well and there are only a couple of minor modifications required (more padding on seat back and file down a sharp edge on the inside of one form).
	Getting ready to try some tricky moves.
A happy paddler.
	First straightjacket roll (just kidding).
McKinley is happy with the result.
	Big smiles after wet exit.
Working on the "stop and turn" concept.
	Good stability (and balance)
A girl and her boat (and Dad).
	To actually be called a folding kayak, a kayak has to, well, fold. After more than a month, I finally got a chance to install the zipper on the back deck. It is a #10 YKK molded marine zipper sewn into a strip of PVC, then glued to the deck.
Here is the boat broken down and ready to pack up. The longest piece is 42" long.
	The "sea trial". We took the Sea Pup on a family paddle on Washington's Lake River (a tributary to the Columbia). We used the floats from the Blue Bomber for some extra stability in the "big water"..
After paddling around for a while, we went into tow mode.
	McKinley liked the fit and feel of the boat, but the backrest hit her in the wrong spot. We are rethinking the design and will probably go with some minicell padding.
Towing from McKinley's perspective.
	Update: 1 year later My daughter has started rolling, so the exposed zipper had to be covered, unless I wanted to keep having to bail out the boat constantly. I designed this covering which is, essentially, a dry bag roll-top. I attached a 6" strip of PVC on either side of the zipper with a 3" overlap. One piece has a 1" wide strip along the top edge to give it a double thickness.
The thicker "lip" is folded over the other flap and the whole thing is rolled down 3 times. 1" cam buckles hold the rolled flaps in place.
	Here is a shot of the unrolled cover. The bit on the end is folded in before the cover is rolled together, providing a water-tight seal.

All images and text are copyright by Marcel Rodriguez unless otherwise noted and may not be used for commercial purposes without the prior written approval of the copyright holder. Noncommercial use is permitted.