I know this has been asked many times.

I would like to build a 1 man 18ft tri out of ply or strip planking.

Is strip planking as strong as ply? Does it cost more (i can easily
get prices for marine ply) and does the strip planking need a coat of
fiberglass over the top?

Apart from being perhaps faster to build with are there any advantages
of ply over strip planking?

N. Peter Evans