Timbo,
It depends on the boat.
If you're talking about the F16 just a layer of 3oz on the deck is all that is required.

If your talking about the F18 it has a layer over both deck and hull.
What web site are you referring to, you may have been looking at photos of building a Taipan.

Regards,
Phill

I know that the voices in my head aint real,
but they have some pretty good ideas.
There is no such thing as a quick fix and I've never had free lunch!