Even small leaks will accumulate a lot of water over a period of time. My
25-footer had a number of small leaks in the deck house and various
fittings. The bilge would routinely have a foot of water in it after a hard
rain storm. By observing from inside while it was raining, I was able to
find the leaks and plug them. No water after a rain storm now.

Also, condensation can contribute a fair amount over a period of time. I put
a small heater in mine during the winter months.

Bob Swarts
"Denis Marier" wrote in message
...
I am returning from a boat shopping trip in North East US. I look at
some boat that have been yard maintained and on land for a while and one
boat in the water. When lifting the floor board on three boat on land and
one in the water I found that their bilge's were top full of water. The
bilge
pumps and float switches were under water. I wonder what the winter sub
zero temperature will do. I have had a sailboat for 24 years and never
had
a bilge full of water. I wonder what could exactly be the cause of this
water accumulation.