Sealing a deck hatch

The boat is an 18' Wellcraft fisherman CC with a self bailing deck design. It has a large hatch for access to the fuel tank, partially under the center console. (maybe 3X8 feet) I would guess there is some sort of a rubber gasket on the hatch. No particular reason to suspect it is leaking, but was thinking about running some sealant along the seam just to be sure. The boat is an '88, so who knows how well the gasket is holding up. I did remove whatever access covers I could on the sides and looked around under there, seems dry. (Did not remove the hatch.)

Would 3M 4200 be a good choice? There would be a lot of foot traffic. Wondering if it will just tend to get loose and peal up anyway. More trouble than it's worth or good insurance?

Re: Sealing a deck hatch

I would not 4200, but use something like BOAT LIFE or you could just use some elcheapo from Lowes or Home Depot. They seal, but not as well as BOAT LIFE silicone. I would not worry about it peeling and it does make a good seal.

Re: Sealing a deck hatch

You don't want a permanent seal, and you don't need a perfect seal; a few drips through there are no problem and your bilge pump is there for this reason. But if you are getting a lot of water through it, try this: Remove the hatch, put down a bead of silicone or other flexible sealant, LET IT DRY and then seat the hatch on it. When you screw it down, it will seal sufficiently for this purpose but still be removeable. Note that you may affect the hatch being flush to the floor.