> There was a thread several months ago describing how to use marine caulk
> to create a thin seal. Esentially you put some plastic wrap over the lip,
> squeeze out a bead of caulk on the underside of the hatch cover and put
> the hatch in place. You can get a good watertight seal that is 1/8"
> or thinner and maintain the flush hatch.

> The trick is getting the plastic wrap to lie smooth on the lip while the
> caulk is firming up. A thin coating of vasaline does the trick. When the
> caulk is partway dry you take off the hatch and peal off the wap. It
> worked for me

I guess I didn't read that post correctly when doing hatches on a canoe--I didn't use the plastic wrap, just a thick coating of vaseline. Worked fine.