I did my old '76 tri-hull a few years ago and the following
year replaced the rest of the floor that wasn't previously done.
It's a pain in the butt because it is time consuming, but really
isn't that big of a deal in itself. As I understand it, the
advantage to marine ply is that it is tight grained, but has no
inherent rot resistance as Joe pointed out. Which is why I went
with treated ply. Besides, I glass over the ply prior to installing
anyway.

Before getting nervous about it, go ahead an rip up the carpet.
That alone will tell you a lot. If it has been glassed/epoxied/etc.,
and this is delaminating from the wood, then you more than likely DO
have a problem and the glass/epoxy is giving you a false feeling of
security since it does add rigidity.

As far as the weak screw holes is concerned, this could simply be
due to the stresses of holding the seat and persons using the seats
over time. Also the fact that the plywood may only be 1/2" thick
and therefore the screws do not have enough bite. In my case
when I originally did this, I went after a roughly one square foot
area that was weak. As I was tearing up the floor to get to solid
wood, it turned into a 9 square foot area. From what you're saying,
I suspect you won't be getting into this kind of project.

Taking out the carpet may be more of a pain than you expect. A lot
could be left behind, depending on what type was used and if the
right glue was used. The carpet glue should be waterproof for this
carpet, but I found (accidentally and AFTER the project was done)
that a little spilled gasoline on the carpet seemed to disolve the
glue almost immediately. I do not suggest using gasoline as a
solvent! In fact, I strongly say Don't!

If you feel your carpet is just holding the water and it isn't
draining properly, try getting the trailer tongue higher (assuming
the boat sits on a trailer).

-Jim

PS: I would no longer recommend treated ply unless you can get the
real stuff (CCA). I picked up a sheet of this new type that Home
Depot sells and feel it is garbage, but time will tell. Lets just
say that after two days of sitting on edge, it developed about as
many waves as the ocean on a stormy day.

-Jim


Chris wrote:
Good day,

In regards to my project boat (75 sunray 15'5) I'm wondering what others
think about wooden floors, and when to change them. From what I understand
the floors of all these boats are built with marine plywood thus they can
take a beating being wet. Now that I've covered the boat I'm letting it dry
up good, and will be ripping the carpet in a little bit. The reason I'm
curious about the floor is that when I pulled out the back seats, some of
the screws essentially came right out of the floor as I suppose enough water
was around them. Going forward I either dry up all the wood, clean, and
paint it then re-carpet, or I look at changing the wood floor (which I do
not prefer to do). I can stand on the floor with my my weight (over
200lbs) and as expected the floor may give a bit in places where there is no
extra support underneath but plywood typically has some flex right. In any
case there's no gaping holes or worn out areas in it, just some screw holes
that appear to be a little weaker around them.

Any ideas?

I have thought about taking out the carpet, waterproofing the existing floor
after a thorough cleaning and maybe even leaving the carpet off (as it
always soaks up water rather than letting the water go away.