In some areas the antifouling might be used for two seasons and in sone areas you need a bottom paint
every year. Grass means the antifouling at the water level is not active any more and might mean further growth on the body might be expected in the very near future. It will be a good idea to apply antifouling as soon as possible. The main growth season is the spring and the beginning of summer for fouling.
Osmosis treatment is not a periodical application. If the hull is dry (check with a humidity meter) a protective coat of epoxy
can be applied to the hull to retard osmosis (please note that epoxy
is better than gelcoat but it also permits some water). If you apply epoxy
on a wet hull, the probability of osmosis defect will increase.
If you already have osmosis on your boat there are three options:
1. Do nothing, wait until it starts inside the layers.
2. Open the defective areas, wash them with hot water, dry them and apply epoxy
coating. These spots will not be affected from further osmosis but other parts of the boat will.
3. Peel off the gelcoat, cover the boat and wash with hot water. Dry it (might take weeks or months) repair
the damaged portions with epoxy and glass fibers. Paint
with two coats of epoxy and apply paint