Four winns Vista 328 Owner's Manual page 120

NOTICE
Improper repair techniques can lead to further
fiberglass component damage.
C. Osmotic Blistering
Osmotic blistering or “boat pox” is an unfortunate but
not uncommon occurrence in fiberglass boats. Fiber-
glass is water retardant, not waterproof. When a boat
is left in the water for a period of time, the fiberglass will
absorb water. It is a natural process that can not be
eliminated in production methods or material selection
and usage. However, there are ways to control and
possibly prevent blisters (see Section P-6). If you do
encounter blisters, be assured that the blisters are
merely cosmetic. They do not indicate a defect in the
boat structure or lamination. Four Winns, along with
most boat manufacturers, regard gel blisters as a stan-
dard maintenance item.
The repair procedure for gel coat blisters is similar to
the procedures outlined in the previous section on cracks
and gouges. There is an exception however, in that the
hull must dry out for several days or possibly weeks
before repairs can proceed.
To determine if the hull has dried sufficiently, tape one
square foot of household plastic wrap securely to the
hull bottom. Make sure all edges are sealed and let it
stand for twenty-four hours. If condensation has accu-
mulated under the plastic, the hull is still “wet” and must
be allowed to dry longer before repairing.
When the repair is completed, an application of an ep-
oxy barrier coat should be considered. This will help
prevent the possibility of reoccurrence of blisters. Your
Four Winns dealer or local ship store will have informa-
tion on barrier coat products.
P - 6 ANTIFOULING PAINT
Four Winns recommends antifouling or bottom paint for
boats which will be kept in the water for extended peri-
ods of time. Antifouling paint reacts with water to retard
the growth of algae, barnacles and other marine growth
on the hull. In addition to marine growth, it offers pro-
tection against excessive water pollution.
Antifouling paint begins reaction upon contact with wa-
ter. After a season’s use or sooner under certain condi-
tions, the antifouling paint may appear to be dissolving.
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This is due to the paint’s chemical emission that in turn
retards marine growth. When this occurs, refinishing is
in order.
Four Winns recommends reapplication of the antifouling
paint seasonally. The effectiveness of the paint will be
drastically reduced if used longer. Though Four Winns
has found the antifouling paints used to provide good
marine growth protection in most water, other paints may
be more effective in certain water conditions. See a
Four Winns dealer for recommendations on antifouling
paint use in your area.
NOTICE
During surface preparation, the hull should be
sanded only enough to remove any foreign mat-
ter, and loose paint. DO NOT sand deeply into
the gel coat, fiberglass cosmetic problems could
later result. After sanding, the surface should
be wiped with a rag treated with a cleaner recom-
mended by the antifouling paint manufacturer.
The surface must be clean and slightly rough to
ensure paint adhesion.
Prior to application of the antifouling paint, the boat owner
may consider coating the hull bottom with an epoxy coat-
ing. Four Winns recommends this procedure as a pre-
ventive and effective means of controlling osmotic blis-
tering. Most major antifouling paint manufacturers also
supply a line of epoxy undercoatings. Consult your Four
Winns dealer for recommendations on epoxy undercoat-
ings.
P - 7 HULL SUPPORT
Proper support of the hull while it is out of the water is
imperative. Due to the design complexities, Four Winns
does not recommend trailers or storage cradles be home-
made. The boat is a valuable piece of equipment. DO
NOT risk permanent damage to the hull structure in an
attempt to save the cost of an adequate support. Improp-
er support can lead to serious and permanent hull defor-
mation.
While lifting the boat, ensure slings are in the
proper locations as indicated by the sling loca-
tion labels . Failure to do so may result in
permanent hull structure damage and will
invalidate the hull structure warranty.
Section P
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