"Jim Thompson" writes:

We want to build a small L-shaped bench for the flybridge on a 30'
powerboat. It will be self-contained (not built into the flybridge).
We want to keep the weight down, and it must be water resistant. What
is the best material? I wondered about 1/4' plywood braced with a
frame of 1x1" wood and covered with epoxy/cloth?

Plywood prices have gone thru the roof, especially 1/4" & 3/8".

Let me suggest something, use 1/2", 4 ply CDX plywood, epoxy and 17 Oz,
double bias (DB170) knitted glass cloth.

It will be light weight and as they say, "Strong like Bull".

Rip some 1" wide strips of CDX and epoxy 3-4 pieces to the basic bench seat
to achieve say a 1" x 1-1/2-2" deep box frame.

Putty any defects in the surface of the CDX with fairing putty, then
laminate a layer of DB170 all around to seal the entire plywood fabrication.

When you are finished, you will be able to jack it up and drive every boat
you are ever going to own under it.

When all those boats are gone, you'll still have the bench.grin

A word of warning.

You need to protect the epoxy from UV damage so paint it with something, say
a high build primer followed by a polyurethane of choice.

BTW, I used 140 sheets of 1/2", 4 ply CDX to build my boat, every square
inch of it sealed with epoxy and knitted glass.

They were used to build the bulkheads, floors and subsole.

Been there, done that.

HTH


--
Lew

S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: http://home.earthlink.net/~lewhodgett for Pictures