: Hello All,

: I am buiding a Pygmy and am making hatches and bulkheads on my own without
: the kit they sell. I have 3mm mahogony ply for the bulkheads and 4mm for
: the hatch lips. Do these parts need to be glassed on each side or just
: sealed with epoxy?
: Do the bulkheads need to be glassed in place or will a fillet of thickened
: epoxy in the corners be OK? The boat is intended for expedition use.

morn'n Jon, not sure if this is help, with a nod to Tom. I built a Coho and used minicell bulkheads. Primarily because I keep collecting chunks of minicell and secondarily because I like the capacity for flexing and minimal flotation in an unladen boat (very minor issue actually but it can't go vertical). It could have been the type of glass layup I used but the bottom of the coho flexes a noticable amount, primarily right under the seat/floor area so a flexible rear bulkhead made theoretical sense. I talked to a fellow that did some major paddling in Florida with a very heavily loaded Coho, he wasn't big but the boat was FULL. He really used the boat, and noticed cracks in front of the aft bulkhead on the floor.

Regarding ply bulkheads I'm inbetween the idea of using thin 3mm ply that can flex and using 4mm ply that's tougher. Again it's probably more theory than real, not much flexing on vertical ply with fillets and glass around it. I'd be more tempted to make a perimeter flange of fiberglass tape or cloth that the bulkhead would sit within then make small fillets, although it's just easier to fillet and glass a little extra at the bottom rear flange. So many permutations to obsess over.

The standard layup is 6oz glass inside and out, for the pleasure of making your expedition kayak weigh an extra few pounds you might consider another layer of 4oz inside the hull/cockpit extending a few inches behind the rear bulkhead up to the front bulkhead with another layer on the outside bottom panels. The ironic thing about overbuilding is that the dings invariably show up outside the area of reinforcing,,or maybe their noticable.

I made an oval VCP shaped rear hatch, it suffered some bending/impact cracks on the center ridge seam over years of rescue practice and occasioanal rental. If your rear hatch is particularly long it would be a good idea to double the 1 1/2" glass tape on the center ridge.

You might consider a 1' strip of 3/8 half oval brass for the stern/bow or graphite/epoxy soaked strips of dynel at the entry lines. Two layers of 6oz glass will disapear in a weeks worth of rough landings in that little strip at the stern. I used nearly 8 narrow layers of 4oz. s-glass at the stern and bow, it's about 1/8" thick and has held up fine so far.