51s should be wood (ply) with teak over. there are many screw holes. the ply will be rotted out. the deck
must be replaced --some after 1980 had frp decks with screw holes. this isnt just formosas.
teak decks are not evil. the installers who placed the 900 bazigillion screws were evil. teak is the best nonskid in the world. go figger. flush with sea water
every day and you have good decking. forget and you have not got anything decent. must be done every day. the quality of teakwood decks is the responsibility of the owner.
owners group on yahoo changed name to leaky teaky yacht club in yahoo groups. there are folks who did their deck replacement with fotos. formosa 51 owners group is good also. these are excellent cruising boats after the deck work is done.
oif this is a pre 1980 formosa--you will have to find someone who knows what he is doing to repair them or go to leaky teaky yacht club and research
the pictures and talk with some of the guys and see what they have to say. mine only need a bit of ply ripped out from underside and more ply inserted in the place of the old dead ply. ..with a bit extra epoxy
and glass to outer surfacing under the sprit.
these are not cored decks until after 1980. until 1980 were plywood
overlay, and that was AFTER the teak was removed.