: Hmmmm .... I hadn't thought about commercial hatches. I had assumed
: I'd have to make them.
: I'll check it out.
A good source (they deal with home builders a lot and have given me great service) for the KajakSport hatches is NewFound Boatworks.
http://www.newfound.com/kayakacc.htm

One approach to installing commercial hatches is Jay Babina's method, which uses a solid wood ring, shaped to fit the deck.
http://www.outer-island.com/Kajakhatch.html
I used that method to install an 'inspection hatch' (flush-style) hatch in my Outer Island (years after building the boat). It would be much better to do this before the deck is joined to the hull, as you can then easily reinforce the joint with under-deck fiberglass.

Now, I prefer to make a glass recess for the hatch using a sacrificial foam mold under the deck. Doing this with carbon fiber on a clear-finished strip boat is still in the future for me; my last couple of boats have been painted.