Something else to watch for - the large capacity bilge pumps need more
current than can pass thru most float switches without excessive voltage
drop.

bob

Pete C wrote:
On Wed, 25 Jan 2006 20:22:45 +1100, "David Flew"
wrote:


I made one discovery soon after buying the boat which was a bit scary. Both
bilge pump discharge pipes ( 1") were plumbed direct to through-hulls about
5" above the water line. This boat is unattended for up to a couple of
weeks. It was making perhaps 1/4 " per day, plus rainfall. And the bilges
had a lot of "stuff" in them - old fishing line, wood shavings, cockle
shells. No solar cell back then. It would not have taken much "stuff" to
either jam the pump and blow the fuse, or clag up the impellor and increase
the running time on the pump ... and flatten the battery. Only happened a
few time before I fitted the second battery. It would not have taken much
for the boat to take a lot more water - it's 40 years old. Loss of one nail
is more than enough to made it 1" per day.


Not a bad idea to have a 'basket' over the pumps and float switch.
Also two pumps running off one float switch gives some redundancy.

IMHO the best way to go is a float switch and two small pumps, then
higher up above normal bilge water levels another float switch and
much larger pump. Ideally run each off different batteries.

cheers,
Pete.