This is a very interesting topic. Anything that can keep the water outside the hull is worth trying.
Recently, I was taking on a gallon or so of water in a smooth lake,
That is too much IMHO.
I tried one layer of Teflon tape in the seal groove. All the hatches stopped leaking completely. I could not find any mention of using this. Is this a bad idea?
Thickness of the tape? In
the seal grove, inside
the O-ring? Or instead
of the O-ring?
Can you please post a picture?
I have not heard of this solution either. If it works, it can't be a bad idea.
Also, why the funky O-ring cross section? Why not a simple circular cross section?
I have read something about that but I don't know where. It has something to do with the hatch being water tight and easy to close/open at the same time. To me, the whole design is too sensitiv to sand/dirt and demand a little too much maintenance, to be perfect.