I now offer kayaks with hatches. The hatch is sewn onto the skin similar to the way a combing is. It can be placed anywhere there are no beams to interfere with it. I use hatches which close with a partial turn. There are no threads to jam.
To install a hatch I drill extra holes in the flange, cut a hole in the finished skin and then drill matching holes in the skin.
The hatch is sewn on with black seine twine. Seal the flange with Lexel and then tighten up the twine. Clean off any residue with a solvent.
Now I have access to the back of the kayak for stowing gear. This baidarka has a low back deck which makes it impractical to stow gear in the back without the addition of a hatch.