Tear up the old floor and try your best to keep the wood in good shape to use as a template for teh new plywood.
Check the stringers for dry rot.
If they are in rough shape, fibergass new ones in. (this may look difficult but the only hard part is leveling them off especially with a tri-hull).
Treat the stringers with a fiberglass resin to aviod future rot as well
The new plywood must be untreated wood, as resin will not seep into treated wood as well as untreated.
Cut the new plywood using the old floor as a template
Saturate the plywood with resin on the underside
use galvanize deck screws and screw the floor into the stringers
Fiberglass the floor in around the edges.
(leave everything to dry for a night)
saturate teh floor with resin to ensure to of floor is water resistant.
after the resin has dried, sand down any high spots and get read to lay the floor.
If using carpet make sure it is boat grade (rubber coated backing) and cut to fit from the back. you can either lay it down on the floor and let the bolted seats hold it down or if you really want to glue it, use carpenders glue and run from bow to stern.
These are basic instructions but should work fine for a 16".
(if you haven't owned the boat for its entire life, dont be surprised at what you find under the old floor. rotingwood, fish bones, gas/oil, tackel, ect. may all be down there. I even found a key.....have no idea how that got there.)
