When it comes to building a good hatch for your boat finding a balance between convenience and a high level of protection from water can be a real challenge.
Jim Michalak says, “All of my sailing boats, except for the tiny dinks, have air boxes which provide emergency buoyancy. I don’t think any part of a boat should be sealed solid. To do so prevents airing out the moisture and water that might accumulate and cause rot.
The air boxes are almost always used as storage boxes, too. It’s true that anything you put in there will decrease the emergency buoyancy. But let’s say you put 50 pounds of stuff, which is a lot of stuff, in Piccup Pram’s aft or fore locker. Those lockers have about 6 cubic feet of air inside, and each would need about 360 pounds on top to submerge the locker. So with the storage you still have 310 pounds of emergency buoyancy. It’s a good trade, I think. The stuff in those boxes is out of the way, never underfoot, and usually stays dry. Now for a hatch for access to the storage area.
I think really proper hatches have coamings and covers like this:
Removable commercial deck plates like the ones that Beckson makes also are pretty good, I think, and not too expensive. The larger ones will allow you to reach a hand into the air box to place small items, but that is.”.. Read More
Kayak Hatches are another thing altogether.