Sealing access hatches

[BurnabyRocket61]

Hello,

What would you guys recommend using to seal those plastic Bomar/Tempress deck, er sole, access hatches. There's that black D sponge stuff, or should I use the likes of 3m 4200 which is semi permanant, and would likely result in a lower profile. Or should I use both, or any other suggestions.

Thanks, and remember to keep your head up, and your stick on the ice.

[Landlubber]

No closed cell neoprene (the black D sponge stuff), is not suitable for installation purposes of the hatch, use 3m 5200 or similar product. The neoprene is quite good to seal the hatch where it closes, not for installation purposes....it is not exactly clear what section you are trying to seal, but because you added a mastic type material, i can assume you are doing an installation job.
Personally, I would not bother with plastic hatches on any boat. Up to you.