wrote in message

I am looking at building a rainwater catchments and filter system on my
next sailboat.
I wonder if anyone has build one and could explain how to make one.


I had a very effective system on my last cruising boat- a catamaran with a
bimini cover over the cockpit area. The total area was perhaps 5 sq metres
and it had a plastic sink drain fitting in the middle. One of the bimini
struts- the middle one- could fold away so that the usual high point in the
middle became a low point. We simply cleaned the fabric every so often and
let the first 10 or 20 litres of rain flush it before draining into
containers. We had fitted filters in the boat taps so left any filtering to
the system that was already in place for all the water.

These filters can get infected so need to be above the bilge so they drain
and should be replaced fairly often. We added a silver sterilizer to the
carbon and flushed the system with bleach/chlorine periodically.

The collection rate was quite impressive- in a good but not extreme rain
squall we collected 60 litres an hour, but light rain might only produce 15
litres. As we were in tropical Australia the rain rate was at time quite
high ;-)

Others will talk of risks with drinking rain water as it may not be
perfectly clean and this is so, but I'm a physician and it didn't worry me
particularly. After all, we do have an immune system and humans have thrived
drinking rain water for millennia. Maybe northern hemisphere rain is more
polluted ;-)

Peter HK