C. Osmotic Blistering - Four winns 248 Vista Owner's Manual

The gel coat must be catalyzed using up to 2% MEK
Peroxide which can be purchased at a supplier han-
dling fiberglass reinforced products. Contact your
Four Winns dealer for assistance.
8. After ample drying time, sand the area using very
fine wet/dry sandpaper. If the appearance of the area
is still not satisfactory, repeat steps 2 through 4 as
necessary.
9. If above the waterline, polish the area using a fiber-
glass rubbing compound and then wax. If the re-
paired area is below the waterline, the area should
be primed and painted in accordance with the anti-
fouling paint manufacturer's instructions.
Gel coat, like paint, will change colors with time and
exposure to sunlight (ultraviolet). For this reason, "match-
ing" gel coat obtained from Four Winns may not match
the gel color of a boat that has been exposed. However,
this is the closest match commercially available. A fi-
berglass technician can tint the gel to be used in the
repair to provide a closer color match.
More severe fiberglass damage, especially when struc-
tural, requires the expertise of an experienced fiberglass
repair technician. See your Four Winns dealer for as-
sistance.
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. Fiberglass
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 lamina-
tion. Four Winns, along with most boat manufacturers,
regard gel blisters as a standard 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 be-
fore repairs can proceed.
Vista™ Owner's Manual
™
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 accumulated
under the plastic, the hull is still "wet" and must be al-
lowed to dry longer before repairing.
When the repair is completed, an application of an epoxy
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 information 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 periods
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 protection
against excessive water pollution.
Antifouling paint begins reaction upon contact with water.
After a season's use or sooner under certain conditions,
the antifouling paint may appear to be dissolving. This is
due to the paint's chemical emission that in turn retards
marine growth. When this occurs, refinishing is in order.
For bottom paint line location, refer to Figures P2 - P7 at
the end of this section.
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 en-
sure paint adhesion.
Section P
Page 5