This is slightly off topic since I building a swim platform rather than a
boat, but they use the same materials and both float...

Anyhow, I found a big pile of 5/4"x6"x5' pressure treated planks, weathered
but in good condition. I figured they had gotten all the cupping and
twisting out of their system and were better than new, not to mention free.
I planed them down to 1" thick and put a tongue and grove on them. I am now
in the process of gluing them together.

I would like your advice on what to do next. I intended on covering them
with polyester cloth and polyester resin. I already have the cloth (I also
have fiberglass, but thought polyester would be a better choice here since
strength is not the big issue) but would have to buy the resin.
I have only used epoxy in the past, but figure polyester will be the better
choice because it is UV tolerant.
Does this make any sense, or am I missing something such as compatibility of
materials.
I will be putting some screws into it after lamination to hold on the
floatation (some large blocks of foam I also found in the street) but they I
don't see that as seriously compromising the structure or the "waterproof"
glue. It would be nice to laminate the foam in with the deck, but that is
probably beyond my capabilities.

Any advice would be appreciated. I realize the whole project is crazy
because of the time required, but being unemployed that is not a serious
obstacle.

(My current swim platform was made 3 years ago entirely out of materials I
found in the street, primarily a old kid's climber and a beat up Snark; but
it probably will not survive another year. I hope to make this one much
better.)