On the Hard?



How many months a year does a fibre-glass boat need to be out of the water to keep the hull healthy?


I'm sorry to say that the answer to this is likely to be be similar to the answer to the question "How long is a piece of string?"

The number of possible permutations of conditions of the boat, the weather, water etc. must be infinite.


New member
9 Oct 2001
Emsworth, Chichester Harbour, UK
I agree with Bob, and can only add that my own Sadler 29 has been in the water permanently since 1985 ( I antifoul between tides). No sign so far of anything untoward with the hull. I did epoxy it from new which hopefully helps.


Well-known member
30 May 2001
North from the Nab about 10 miles
12 months!

in other words the only way you can be totally certain of preserving the hull, is - not to use it!

Then watch the yard hand back the mobile crane into it and write it off....

Seriously though, the advice to epoxy it before it ever tastes the water is about the best way of ensuring a long and trouble free life. Otherwise, it may start developing problems after anything between 1 and 20 years - and in some cases even longer - or shorter.

So much will depend on the conditions under which the fabric of the hull was built - age of the resin, thoroughness of the mix, temperature and humidity of the materials while in store and being mixed and used. How carefully was the resin mixed, and applied.... and so it goes on.

Then, once completed and launched, the conditions to which the hull is exposed - the salinity of the water, the temperature etc. All these and a lot of other factors appear to play a part in the speed at which a hull develops Osmosis, or any of the other nasties that can, but do not always happen.

Allowing the hull to dry out for 6 months of the year may help, although the rate of drying outdoors in this country over the winter months cannot be very high! The only certain thing is that if your hull is set to develop osmosis, say after 5 years in the water (and I do not know of any way of finding that out beforehand) , then it will presumably not do so until 8 or 10 years, having spent half the time out on the hard, - or perhaps someone knows better?

Almost makes you envy owners of wooden boats who only have straightforward dry rot, wet rot, gribble etc to worry about.....