Is bottom paint (hard or ablative) actually waterproof?
I realize that it is applied to prevent growth. But does it actaully act to prevent water from entering the gelcoat and resin/fiber?
I don't believe my boat model is know to have blister problems, and my 30 year old hull (in water 7 months / year) does not have any, but after reading the above link on blisters, I guess it is possible to have water damage / weakening of the hull, without blisters.
Without the any apparant damage / blisters, it is hard to justify the work / cost of stripping down and applying a true barrier coat.