Is there a way of telling what kind of bottom coat is on my 82 Catalina 30. It's black , sands very easily and will come off on your hand if you rub it. I have a can of interlux bottom coat called Bottomkote XXX antifouling paint that someone gave me free, so do I just clean the bottom and put this stuff on? I tried interlux web sight but no real help. If I just put in on, it can't do any harm, can it ????