4 years ago I built a 22' center console, plywood / epoxy and during the
construction I asked a lot of questions here. Anyway one of the questions
was whether to use SS screws or silicon bronze. A lot of people said the SS
would develop crevice corrosion. I am doing some repairs and have taken out
a lot of the screws out of the bottom that were sealed under epoxy. This
boat has spent about 5 months of every year in salt water since 2000. The
screws I removed look identical to brand new screws now. Also the boat was
entirely made from hardware store fir plywood rather than marine plywood
which many also insisted on. No problems yet. I am not trying to convince
anyone of anything but if someone wants to build a boat on a tight budget
there is no reason not to use SS screws and exterior plywood as long as they
use epoxy /cloth with it.