will not take compression
loads so doubt very much that the deck under the mast is that. Typical construction on a deck stepped mast is to put plywood under the mast if it is not solid FRP and solid FRP is not common. Would bet it's plywood. Only thing you can do is pull any fasteners around the mast step and check to see if the core is wet.
The Cal 40 had a steel
load bearing weldment under the sole to spread the load of mast compression. Many, if not all of these have corroded away and either have been replaced or need to be replaced. If the 34 had the same type of keel
mast base, your surveyor should have noted the condition of the step on the survey
. If he hadn't specifically noted it and the material it's made of, I'd question the surveyor and find out what he'd found. If there was enough corrosion
on the mast base to warrant correcting the problem, there's been a long history
of saltwater around the base. Would really want to be sure whatever the mast is sitting on is still solid.
Common fix for this problem is to have a new mast seat made up that is the height of the material that has to be cut off the mast to get rid of the corroded area. That way the mast is the same height as orginal
One good idea on buying a boat
is to be there when it's surveyed. Going over things directly with the surveyor as he's doing his inspection
just after he completes the survey
are a real benefit to you. You may have been there, but it didn't seem like it from your post.