: Thickness may not be a relevant issue.

: There is probably no requirement that the hull be of a uniform
: thickness, so you can start with very thin material and increase
: the size and strength in areas where such reinforcing is
: required.

I don't know what limitations you may have.

When I was studying unique freeform engineering (sculpture) in art school,
we had a lot of fiberglass mat and polyester resin available for some reason.

Some people liked to color polyester resin and pour it on plastic sheet to make
tie dyed, stained glass like, panels. Looked cool, but the resin without reinforcement
was like peanut brittle, any impact shattered it. But use the polyester resin with fiberglass
mat and we built huge sculptures that were very strong.

We soon heard about sculptors who got sick because they didn't wear respirators or dust masks.
So we suited up, like deep sea divers and got covered in goo and dust.
I hated the mess and stopped working with polyester resin and fiberglass.

Then I shifted to bronze casting. But after our bronze furnace blew up, and our foundry was condemned,
I was forced to find other work methods, so I started working with plaster.

Plaster is a very traditional sculpting material, where you start with a wood frame, build
volumes with chicken wire, or hardware cloth, and cover that with burlap soaked in plaster.
Then you add plaster on top of that and carve hardened plaster, or model wet plaster to
create the finished surface.

(After all that work you can see why I love how easily wood strips create a surface, and why I keep harping on aligning strip edges.)

I wanted something lighter, I wanted something stronger, so the figures I made would stand on their own feet.

I thought how plaster without burlap was brittle and shattered easily like polyester resin without fiberglass.
So I tried plaster with fiberglass mat and it was extremely strong and extremely light weight. This is the basis for
my life size plaster figures shown on my web site.

The beauty of the fiberglass mat is that you can soak small hunks of it in plaster (concrete?) and apply it to a surface
covering any kind of shape. Small strips of fiberglass cloth might work also.

I could tell you what I'd do, but that gets into the area of consultant fees.

Good luck! But wear a PFD!

Rob

I've seen these races for years. The winners have learned to paddle.