Hatch core material?

[SBD]

I have one large hatch that covers my fuel tank (39x39) and it is a little squishy. I thought while I have everything torn apart I should re-core it. What should I use keeping in mind I live in a rural area and have limited sources for material.

Thanks!

[Bigshrimpin]

4" x 4" x 1/2" inch plywood squares work great!!

[aldo]

Nida-Core comes in 2'x4' sheets(ships easily) and is strong & light weight. Can't tell you how happy I was with the result on my floor.

[SBD]

Plywood is certainly cheap and available, anyone ever use blue foam?

[Blue_Heron]

...anyone ever use blue foam?

Sean,
I have, but I wouldn't use it for something structural like a deck hatch. Polystyrene is susceptible to attack from all sorts of solvents, including gasoline, motor oil, and polyester resin. It also has pretty low shear strength which is what you need in the core of a cored laminate. A large person on top of that hatch when you're in a heavy sea could cause a styrofoam core to fail.

All that being said, if you can protect the core from solvents, and you make it thick enough that the shear forces are low (say 1.5" thick), it could work. I just don't think the weight and cost savings are enough to make it practical. I would go with plywood blocks like Bigshrimpin suggested, but for a hatch that big, I would go with 3/4"

Dave

[SBD]

All we have here are heavy seas so looks like I'll skip any desire to experiment. Good to know thanks a bunch!