Almost all makes of fiberglass boats get blisters at
some point in their life. You should rely on your
surveyor to advise you about the severity of
blistering on your boat. Blisters are primarily a
result of the type of resins used in manufacturing,
the conditions present when the hull was laid-up.
Generally, the small, shallow 1" or less (in
diameter) blisters are viewed as cosmetic defects.
When they become very large (3" plus) and penetrate
several layers of laminate then they can be regarded
as a structural problem. The cosmetic types can be
fixed for around $10/blister. If there are
structurally threatening blisters then a bottom-peal
may be required which costs substantially more.
Remember, all wooden boats rot, metal boats get
electrolysis and fiberglass boats get blisters
eventually.