I apologise in advance for the following rant .....

I feel a switch is important - it needs only be a simple on/off switch in
parallel with the float switch. It lets you test run the pump without
lifting the floors. My boat runs with quite a lot of water in the bilges -
rainwater and sal****er washdown. So whenever I visit for a quick check I
can test run the pump and be sure it's delivering at full flow. And that
the fuse has not blown. It also lets me remove water below the "cut-out"
level for the float switch - useful if I'm doing a big wash-down and want to
keep the water flowing to the pump. Only issue is if I should leave the
switch on and run the battery flat, but the pump is noisy. You could use a
momentary contact switch, but if you NEED the pump, you probably can't be
there holding the switch. The second pump does not have a float, just a
switch. It's connected to the engine battery, and is thus isolated unless
I'm on the boat.

My boat does not heel, and I'm not a lover of check valves. They come
second on my list of things which fail after pressure switches ...... but
that's my industrial experience showing, why should I think that boats will
be better ???

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.

5" of extra water in the bilges is not in itself a disaster - it's over the
floorboards, but not into engine or electrics. .
But as I purchased it, 5" was enough to take the bilge pump outlets under -
and then there would be two x 1" holes in the boat. Hours and it's down
......

I've since re-routed the hoses so that they are looped much higher. With no
check valve, they drain back once the pump stops, so there is no siphon.

And before anyone asks, the previous owner visited the boat every second
day, so this was not an issue for him.

I hope the above will help someone else eliminate some of the things which
can go wrong - at least some of those I've found.
David



"johnhh" wrote in message
...
Many of us think the on/of/auto switch is a bad idea. It is far to easy
to turn it off unintentionally. My preference is just on/auto. Fuse it,
not circuit breaker which is too easy to turn off. It should bypass the
then main DC house switch. If you need to turn it off to work on it, pull
the fuse, but make damn sure you put it back and test it.


"Graham Frankland" gfranklandattiscalidotcodotuk wrote in message
...
wrote in message
oups.com...
I have a manual bilge pump in a Newport 27, and
would like to add an automatic electric one.

What is the easiest way to do this? Can I use
(at least some) of the hoses that the mechanical
membrane pump uses?

The membrane pump is mounted in the back of the
cockpit.

Can I put both pumps on the same hose, i.e. can I pull
water through an electric (rule) pump when using the
manual, and can I push water through the membrane
pump with the rule?

If not, what is the next best/simplest setup?

Thanks for help and suggestions,

They can physically be plumbed in line but it's a bad idea as it
drastically restricts the flow and, more important, one problem could
affect both pumps, leaving you unable to pump out.

Although there are some electric pumps with integral auto switches I
always prefer separate simple float switches wired through a dedicated
on/off/auto switch, connected directly (via a fuse but not through the
isolator) to a domestic battery. Although it slightly restricts flow
rate, I always fit a non-return valve in the outlet to the skin fitting
to avoid any chance of back feed when heeled.

Graham.