Installing Bilge Pumps

[bstreep]

Originally Posted by Pblais

Consider the jet ski. Very small boat, very big pump, and no bilge.

Actually, there is a bilge, and with the "very big pump", it's also a very big bilge pump. They have an air/water separator on them (for water coming over the top), and the intake water goes into that bilge.

[sarafina]

Originally Posted by Pblais

Consider the jet ski. Very small boat, very big pump, and no bilge.

yep, and jet skis are so all about *overcompensation...*

; -)

[off-the-grid]

Originally Posted by sarafina

there is an ancient manual hand pump that is not functional... original I suspect. it's good she's watertight! Like this one.

I planned on replacing it so we would have a manual back up. Good idea or no to use one like this?

Better than nothing. When my engine compartment decided to leak and flow into my port aft cabin, that's exactly what I used.

[off-the-grid]

What about me?

Catamaran with very shallow draft and very shallow bilge. So they're going to have to be small pumps, just to fit under the sole. Based on the responses here, the extra buoyancy I'm adding (which by the time I'm done, should be almost enough to float the boat even if flooded), and the hand pump I have as a backup, I'm thinking 1 pump/hull, directly to battery, no float, with auto/on/off switch.

I'm also thinking of running the hoses, up under the cockpit floor and then back down into the self draining rudder cages, to avoid adding 2 extra thruhulls. The deepest part of my bilges are pretty far back, so this isn't really a long run.

Lastly, propane sensors apparently work pretty well as water alarms too. At least they will once replaced. Stopped working after that last flood.

[sarafina]

OK, Lots of great stuff here, thanks for all the feed back. We have been talking about it and I crawled around yesterday looking at stuff and this is what I am thinking now;

One electric pump, like that rule 2000;

Rule 3700 Gold Series Bilge Pump.

but not automatic. She is very dry and I don't see any reason to have a pump cycling on over and over. (Would have loved one of these on our old woodys though!) I like the built in strainer, but will be adding another strainer around it as well.

A float switch. I thought about using an ingenious installation with a float attached so the switch isn't actually in the water, which rises and triggers the switch. I have cleaned off and replaced way too many gummed up float switch... But as clean as this bilge is I think that would be over kill... so just a nice simple (always a good idea in my book) standard setup. Heavy wires, fuses, manual override yadayadayada...

A new manual pump installed to replace the old leaky one. This is already plumbed thru the hull, so I plan on running the new electric pump to the same line for discharge, no need for a second thru hull that I can see.

A whale foot pump in the galley will be on a y valve so I can normally pump fresh or sea water with it. I am going to make sure there is sufficient length on that hose so that I can, in an extreme emergency, turn off the water supply, disconnect the y valve and run that intake hose down to the bilge to pump as well. and I get that after the emergency I would have to replace the hosing and pump to avoid foulness and disease... small enough price to pay I figure.

and one last back up; I got the OK yesterday from Himself to rig myself a shower. I will be using a small portable pump to drain out the shower pan and in an emergency that pump could also be dropped down in to the bilge and run as well, so that's 4 pumps in a worst case scenario. 2 electric, 2 manual. The bad news is both manuals will be in the cabin... no way around that really. I looked at that gusher and we just have such a tiny cockpit I think it would be a hazard to have it installed there as much as I liked that idea. The good news is the manual pumps are in such close proximity one person can run both at the same time. Tiring, but if both were needed I guess there would be sufficient motivation...

If one of us is singlehanding then I guess in case of emergency you just turn on both electric pumps and hope for the best. the two of them would move 4200 GPH, which sounds like a lot of water as I am sitting here in my living room... hopefully it will still seem like a lot if there is a problem and the system is needed...

nice install info

Sound like a plan?

Gruntzer; any chance that should you wind up with water in the cockpit it could be diverted back into the bilge thru that line to the pump? would the pump read water in the outtake as water present PUMP!

Thanks for all the help!

[off-the-grid]

Originally Posted by sarafina

Gruntzer; any chance that should you wind up with water in the cockpit it could be diverted back into the bilge thru that line to the pump? would the pump read water in the outtake as water present PUMP!

Thanks for all the help!

Zero chance.

My cockpit drains directly into the water. the hose would be routed up and under the cockpit floor, then down into the rudder cage. And water accumulation under the cockpit floor, will eventually make it's way into the bilge anyway hose/or not.

[David M]

Originally Posted by sarafina

OK, Lots of great stuff here, thanks for all the feed back. We have been talking about it and I crawled around yesterday looking at stuff and this is what I am thinking now;

One electric pump, like that rule 2000;

Rule 3700 Gold Series Bilge Pump.

but not automatic. She is very dry and I don't see any reason to have a pump cycling on over and over. (Would have loved one of these on our old woodys though!) I like the built in strainer, but will be adding another strainer around it as well.

A float switch. I thought about using an ingenious installation with a float attached so the switch isn't actually in the water, which rises and triggers the switch. I have cleaned off and replaced way too many gummed up float switch... But as clean as this bilge is I think that would be over kill... so just a nice simple (always a good idea in my book) standard setup. Heavy wires, fuses, manual override yadayadayada...

A new manual pump installed to replace the old leaky one. This is already plumbed thru the hull, so I plan on running the new electric pump to the same line for discharge, no need for a second thru hull that I can see.

A whale foot pump in the galley will be on a y valve so I can normally pump fresh or sea water with it. I am going to make sure there is sufficient length on that hose so that I can, in an extreme emergency, turn off the water supply, disconnect the y valve and run that intake hose down to the bilge to pump as well. and I get that after the emergency I would have to replace the hosing and pump to avoid foulness and disease... small enough price to pay I figure.

and one last back up; I got the OK yesterday from Himself to rig myself a shower. I will be using a small portable pump to drain out the shower pan and in an emergency that pump could also be dropped down in to the bilge and run as well, so that's 4 pumps in a worst case scenario. 2 electric, 2 manual. The bad news is both manuals will be in the cabin... no way around that really. I looked at that gusher and we just have such a tiny cockpit I think it would be a hazard to have it installed there as much as I liked that idea. The good news is the manual pumps are in such close proximity one person can run both at the same time. Tiring, but if both were needed I guess there would be sufficient motivation...

If one of us is singlehanding then I guess in case of emergency you just turn on both electric pumps and hope for the best. the two of them would move 4200 GPH, which sounds like a lot of water as I am sitting here in my living room... hopefully it will still seem like a lot if there is a problem and the system is needed...

nice install info

Sound like a plan?

Gruntzer; any chance that should you wind up with water in the cockpit it could be diverted back into the bilge thru that line to the pump? would the pump read water in the outtake as water present PUMP!

Thanks for all the help!

I would go with two separate thru-hull discharges for a few reasons.

1. You will need to install two check valves in order to prevent backflow from one pump to the other. Two check valves means an increased probability of one of them sticking.

2. With two separate discharges, you will have more dewatering capacity (lower restriction through the thruhull outlets) than if you have two pumps trying to push water through the same hole. You may need both pumps working at 100% if you start taking on a lot of water.

3. Another nice trick with two or more outlets is that by looking over the side, you can see which pump is running and more importantly, how fast each pump is pumping. Those red lights on the pump control switch frequently burn out.

The GPH rating on the pump is never reality. Its not even close. Pumps are tested at 13.8 volts, no pressure head and no resistance from the discharge hose, valves, adaptors or outlet connections. Bilge pumps are high volume, low pressure pumps...so any restrictions really slow down their flow rates.

On passenger vessels, the Coasties prohibit combining discharge outlets from different pumps for those reasons.

Be sure to add a valve, even for discharges above the waterline.

[Pblais]

Gruntzer; any chance that should you wind up with water in the cockpit it could be diverted back into the bilge thru that line to the pump? would the pump read water in the outtake as water present PUMP!

No that would not be a good idea. Water in the cockpit needs to drain on it's own by gravity and hopefully fast. Sending any below sets you up in poor shape for the next time it comes in. It's not a common thing but when it happens it could happen again.

Only the float switch operates the pump. Even the asutomatics need water actually in the bilge to operate. You don't send water to the bilge on purpose. It might get there under ordinary circumstances not by your doing.

Two check valves means an increased probability of one of them sticking.

I've had that happen. Dont share discharges. It is possible they both need to drain at the same time and it is liklely to be a time when you would prefer they both work 100%. Don't force situations that would make things worse.

[pressuredrop]

a question for those of you that have check valves on your bilge pump hoses to prevent the water in the length of the hose from returning to the bilge.

i have 2 rule pumps, an 1100 (built in float switch) deep and the bilge and a 3700 up higher with an oldschool float switch, the small pump has a check valve that is no longer working (as the water from the lenght of the hose finds its way back to the bilge, but i was just thinking, the check valve is at the bottom of the hose near the pump, so even if it was working i would still have a hose full of water. got me thinking that i should replace the check valve and move it very close to the thruhull. what say yee?

[GordMay]

Remove all check valves, and install an anti-siphon loop c/w siphon break (vent), to keep water from back-flooding. Loop the discharge hose as high as possible, then lead it down to the through-hull (exit @ 8" min above waterline). The anti-siphon valve must be installed so it's above the heeled waterline at all times.
To avoid airlocks in the system, discharge hoses should rise continuously from the pump to the anti-siphon vent, with no drooping valleys.

See also ➥ Cruising World - A Simple Valve Prevents Flooding

Not my dwg, but good visual:

[sarafina]

ok, back to the drawing board....

[velero]

Does anybody knows what the NMMA and ABYC sizing requirements are for bilge pumps?

[GordMay]

ABYC H-22, and the NNMA are silent on bilge pump capacity recommendations.

The CFRs (33 & 46) have minimum requirements for commercial vessels, depending upon size & passenger capacity; beginning with:
1 fixed power pump @ 10 GPM (38 lPM) AND and 1 portable hand pump @ 5 GPM.

[pressuredrop]

Gord - does the use of a vented loop also apply if the pumps exit the transom? (the boat is not a canoe/rounded stern), might the use of check valve be better to prevent following seas from entering?

[GordMay]

Originally Posted by pressuredrop

Gord - does the use of a vented loop also apply if the pumps exit the transom? (the boat is not a canoe/rounded stern), might the use of check valve be better to prevent following seas from entering?

Others will certainly disagree; but I wouldn’t use a check valve, and ABYC doesn’t permit them in this application.

If the discharge is above the heeled waterline, no backflow prevention is required; but I'd still prefer to see a loop in most installallations.