Backup bilge pump

[guydickinson]

I've been advised (v sensibly I'm sure) to have a backup to my main manual bilge pump - perhaps electric? Initially a bit loathe to make more holes in the hull - but safety first I guess. Any thoughts on the best bet??

 

[fluffc]

Put holes above waterline and/or 'Y' into existing (above-waterline) outlet??

 

[nordic_ranger]

Why make another hole in the hull just 'T' or 'Y' the electric pump into the existing outlet.

 

[guydickinson]

Good idea - the pumped water won't try and go the wrong way I suppose! Would you go for elctric as a second - in which case what is a good compact pump?

 

[fluffc]

You will probably need a one-way valve in the electric pump outlet pipe. The manual pumps' valves would stop water going the wrong way back through the manual pump, but electric pumps are mainly centrifugal or impeller type, without a 'valve'.

 

[roger]

Valve or not?

Most of these pumps are centrifugal and surprisingly good. Like alll pumps they block up with debris in the bilge which is an argument for keeping bilges clean. The valve prevents reverse flo but will add extra "head" to the pump reducing flow. CF pumps are usually on the margin for head anyway. If you put the outlet where it is always above water you may not need a valve.

 

[samwise]

Get one with a built in float valve, the separate ones are fiddly to fit. One of the mags did a test on a batch of pumps within the past year I think (Just looked it up, Sailing Today did one in June 2002) Anyway. Rule are pretty good, I bought an Attwood with integral float unit because it is a nice compact unit. It works OK, but I wish I had bought something a bit more powerful. If space isn't a problem, I would probably go for a Shurflo, not cheap but when the bilge water is rising it could be money well spent.

 

[tangofour]

I have a bilge pump and 2 shower sump pumps al tee'd into the same outfall pipe. Each has a non return valve before the main run to the exit. The non return valves are not perfect. Although they stop any noticable flow of water from bilges to showers or visa versa they do set up an interesting problem. About 2 litres of water very slowly bleeds back from beyond the bilge non return valve setting up a 20 minute cycle of run pump for 10 seconds, wait, run pump, wait etc. Its the same 2 litres of water running back and forth.

Not sure how to fix this? Better quality non-return valves appear to have stronger return springs thus presenting a bigger impedance to the pump.

 

[mikefleetwood]

Make sure the tee is raised above the level of the outfall, then there will be no stored water to leak back.

 

[Mirelle]

Two manual pumps?

I have two Henderson Mk V manual pumps, one in the cockpit (never used) and one below deck. The one below deck gets lots of use as, via a diverter valve, it also empties the galley sink.

Both discharge hoses run up to the deckhead then down to a non-return valve above a Y piece above the outlet seacock, which is about halfway up the topsides. It may not be pretty to have the seaock in the topsides but the set up seems bullet proof; had it that way 20 years now.

 

[smb]

I thought all float switches had seperate 'ON' and 'OFF' levels to overcome exactly the problem you describe.

That being the case seems your 2 litres running back into a smallish shower sump is enough to raise the switch to the higher position. As an alternative to stronger one way valves is a smaller bore pipe viable (shower pumpout only). That might reduce the volume of water involved sufficiently so that the switch does not reach the higher 'ON' position whilst still managing to pass your short and curlies without too much trouble. /forums/images/graemlins/tongue.gif

Just as an afterthought. Your sure its the same 2 litres coming back in and not the beginnings of the whole ocean being syphoned back in, only being thwarted by your shower pump? /forums/images/graemlins/shocked.gif

Steve

 

[pampas]

Had the same problem cured it by raising the float switch to a higher level, leaves a bit of water in the sump but it has cured the cycling problem.

 

[Becky]

To a certain extent it depends on the amount of battery storage you have; the size of your boat, and if you ever sail singlehanded, or with a weak crew such as a child.

We have just replaced our back-up electric bilge pump with a much bigger one, because we have been in situations where is wasn't big enough. We were taking green seas over the bow and water was coming down the anchor chain pipe.

Without adequate batteries, stick to manual as pumps can consume copious amps. But for convenience, as big a bilge pump as you can afford on an automatic switch is a godsend in really bad conditions. And it leaves you free to do the sailing/manual pumping.

IMHO anyway

 

[vyv_cox]

- stick to manual as pumps can consume copious amps. -

The manual ones also consume copious muscle power. If installing a manual pump intended to really move some water, site it so that legs and back do more than arms. My emergency bilge pump bolts to the companionway steps with the handle vertical, at just the right height for me to rock fore and aft on my legs. In tests, after a painful and tiring mishap after which I modified the previous arrangement, I was able to carry on pumping for a considerable length of time while trying to empty a bucket that was being filled by a hosepipe. In this case I simply pump the water into the cockpit, no additional holes at all.

If you have a deep bilge then it is only necessary to T into an existing inlet and strum box. On a shallower-bilge boat it's wise to consider an alternative location. On the Sadler 34 the standard bilge pump drains the engine bilge. Water entering somewhere forward needs to be sufficient to nearly sink the boat before this pump can be used.

 

[Stemar]

Unless you get a monster, an electric pump is unlikely to deal with a serious leak, but will certainly help to keep the bilges dry, which has to be a good thing. It will also pump when you're not there - at least until the battery goes flat!

I recently fitted an electric pump with a separate float switch. The switch doesn't kick in until the pump is well immersed, so it does leave an inch or so of water behind, but I put a three position on - off - auto switch on the switch panel, so I can clear the last little bit on manual. I wired it so that when the pump is on, an LED lights and if the float switch tries to turn the pump on but the manual switch is off, an alarm sounds. This needs a double pole switch. PM me if you'd like a circuit diagram.

 

[santeana]

I'm uneasy about the simple solution of just putting a T or Y into the existing outlet. In extremis you'd want the full potential of both pumps to be available. I have doubts if the original single pipe would have the throughput to be effective under such conditions.

 

[Tomkat17]

I have a back up bilge pump set up in the saloon with the suction side attached to a lenght of hose. The output end has a hose which will reach into the cockpit. No additional holes in the hull are required. This allows both pumps to be operated in an emergency.

 

[santeana]

...and if you've taken a biggie over the stern and the cockpit's full.....? What goes out = what's pumped in?

 

[Tomkat17]

Not every boat has a bath for a cockpit which doesn't drain quickly.

 

[santeana]

Yes, quite true; not every boat - but not the time to be topping it up and hardly a recommeded standard practice. Guess it's a personal opinion and I respect yours'.