I was most fortunate that PRESTO only had 6 small blisters about the size of a dime.
I had the bottom stripped, blisters repaired (epoxy filler with epoxy top
coat) and recoated with Interlux Fiberglass Bottomcote. The bottom job was done in MAY of 88. That makes it 4 years old now. Before the racing season Wesley and I dive on it with a soft bristle brush to wipe off the thin layer of slime that forms.(fresh water) The slime layer still comes off with a brush but the layer is getting thicker. I expect that this is due to the copper being leached out of the bottom paint.
The importance of a clean bottom will make the difference between running
with the pack and pointing a little higher where they can not go.
Another bottom compound that has been used is
VC17 on a Hunter 25.5 in our fleet and with a clean bottom she out
sails her handicap.
For technical questions on bottom paint:
The photo on the right is from Chad Wilson of #223, Bell of the Ball. From the JPGS he sent it appears that she was lifted from the keel bolts. I do not know if it is detrimental to lift from the keel bolts, they are a little forward in the hatch. But it proves that it can be done. Note the clean bottom!