rad thru old posts and still need help

Ok my 1969 18ft glasspar that was going to be some new seats and off to the water has turned into a major project. Right now I am on the floor, I have some of it cut up, and this is what I found and what I need some advice on.
It is a tri-hull and there is a "ditch" that runs down the center to channel water back to the pump. most of it is 6 or so inches deep, it comes up on each side and turns outward towards the sides of the boat, it has some sort of webbing in it (I think for strength). Anyway it is all filled in with foam along side of this then there is what is left of a 1x10 board that fits between the foam and the lip that turns outward. so basicly the wood is just a 1x10 laying flat on top of foam. I didnt cut real close to the edge yet but I think there is another piece of wood along the edge with the foam inbetween the 2 pieces of wood. The foam inbetween the boards is about 6in wide and veries in thickness due to the shape of the bottom of the boat. I hope you understand what I am saying, any way I was looking into some new foam and dont know what to use, seems everyone goes with 2lb. but I wonder with the way this boat was built if the foam doesnt serve as some sort of structure also, so should I use 4lb.?? Then pretty much from what I read I use a epoxy to coat the wood and put it all back together. Sorry this is so long but I tried looking at everyones pics and they dont even come close to how mine is built. Thanks

[steph]

ok, so I think I need atleast 4lb foam after looking at how it is built. Now I need to know what is the best way to fix the floor? I plan to keep the boat around for awhile, I worry that if I cut to within 4in from the sides all the way around and do it that way that if there is wood along the sides ( like stringers) I wont be able to get to it to seal it up due to the shape of the hull and in a few years it will rot and I'll be repairing the sides. I doubt if there is wood there as the floor sits right on the hull where the fronts of the lounge seats are.

I am not thrilled with the idea of cutting out clear to the sides either, so what to do?

I also wonder if anyone has ever used durabak on there sole? If your not fimilar with it type in www.nonslipcoating.com they also have a smooth kind with no granuals in it. several coats of this sounds alot easier than fiberglassing the whole floor. I know, I know easier is not always better.

[Jets]

Steph,
Try http://www.classicglasspars.com/. I amsure that they will point you in the right direction.
Gerry