ASA and PSIA Instructor
Join Date: Apr 2000
Thanked 27 Times in 27 Posts
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Sailing with a blistered bottom would be like permanently dragging an anchor behind the boat.
Leave any gelcoat that it is well-attached. Don't mess with the boot top unless that area has blisters, which would be a red flag you got real problems.
If your boat has a cored hull, hire a surveyor to test the hull for wetness and delamination, although I guess after two years even a compromised cored hull may read dry, but a good surveyor should be able to figure out what's what..
Remove any loose material from the blisters then fill the blisters with Interlux Watertite. Sand as needed. You may need to do two or three fills for the blisters to be faired. Spend as much time or yard money as you can stomach getting the bottom fair - you hopefully will live with this finish for a long time. Apply 5-6 coats of interprotect 2000E.
Properly barrier-coating a bottom is a simple but time-consuming and tiring job. For a 30' boat with s blistered bottom, assume 5-10 full work days and $5-800 in materials.
Having a good bottom on a boat you are going to keep is well worth the cost and effort.