The reasons for coming up with this alternative design were the mistakes I made when I built my second PakYak to the original plans. I wanted to make the skin a little tighter on that one, so I ran the seams a little "inside the lines"; but I guess I overdid it, because it's a bear to get the zippers closed. As a result one of the zippers gave out and I had to replace it.
In thinking about this situation, I realized I wasn't taking full advantage of the frame set-up leverage to stretch the skin, because I wasn't attaching the rails until the frame was fully set up. So I worked out a way to hook the rails to the frame before the frame is fully spread.
I extended the rails to the end frames to take more advantage of using the leverage to stretch the skin, instead of depending on the zipper closures. So now we have the option of leaving the boat "open" or putting decks on the ends. Although I haven't had this new PakYak in any chop, I expect the end rails will deflect waves that wash over the bow better too.
Then I added the center thwart both to give better knee clearance with the cockpit deck on and so that deck will shed water better (the flat deck let water pool a bit where it sagged in the middle).
1. Rail extensions: four two-foot rail pieces extend the side rails to the center of the end frames and replace the mid top stringer. They are attached to the center rails by one-inch hinges, located on the inside, so the rails can straighten and fold with the skin.
2. End top stringers: these no longer have to be doubled and an extra inch long to accommodate the folding of the mid top stringer. They are a single piece the same length as all the other stringers, with a bracket on the end that pins to the rail ends. (above)
3. End side stringers: These also are now the same length as the other stringers, so the folded frame is even across the end. They have hooks on the ends to engage an elastic cord on the other three end stringers. (right)
4. Mid frame top brace and locks: a 6-inch piece of 1" by 1/16" angle
is cut and folded to fit over the top of the frame opposite the
vertical brace plate. This piece limits the vertical swing of the
brace arms and holds them square in the set up position. The
brace arms are locked in position with pins. The pins are on straps
that wrap around the brace and snap in place to secure them. (below)
5. End frame top brace: this has a similar top angle piece, but without the pins. (The straps hold the brace set up.)
6. Rail to brace hooks: the rails are attached by means of hinges, which have been "uncurled" so that the center part forms a hook. These are two inch hinges at the center, which also form the top plate of the center rail hinge. Here the hook part of the hinge is on the rail and the pin part is on the top of the vertical center brace (shown with the rail rotated up).
At the mid braces the hooks are made one from one inch hinges and the hook part is on top of the brace arm. Locking levers are used to keep the hinges from unhooking during setup.
7. Center side brace: to accommodate the new rail attachment system, this has to be able to swing into place after the rail is attached. This is achieved by running the side stringer tension cord through the brace parts, and hooking it to pins on the rails (after the other braces are set up).
8. Seat: The canvas seat is replaced with a ¼" plywood piece, covered with a piece of foam and canvas, attached to channel strips that fit over the bottom stringers. The seat is held in place with straps that wrap under the stringers on the center end and snap closed.
9. Skin: The skin was made from one piece of polyester awning canvas that wraps fully around the frame (instead of using separate top and bottom pieces). This reduces the number of seams and allows the foam liner to be wider. [However it does make it more difficult to cement the foam in place at the ends. (Next time I may try cementing the liner foam and fabric in place before sewing the end seams. This would solve the difficulty.)] (right)
10. Center thwart: This is an added feature. It has a 3-inch rise in the middle to give more knee clearance and help the fore deck shed water. It is hinged for folding, and attaches to the center brace hooks.
11. Decks: Triangular end decks replace the zippered section of the previous skin design. These incorporate a strip of foam padding to serve as back rests on the mid braces. All the decks are Velcroed to the skin under the rails. The four deck sections serve as the pack cover when folded.
12. Paddle: Sevylor has come out with a new breakdown paddle design. It is a seven-foot paddle that breaks down in four two-foot sections (one shaft section is a bit shorter). It is a sturdier paddle than the old telescoping model (which can be a bit longer), but adds a pound to the weight.