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How not to install a bilge pump!
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| tedious |
Posted on 05/29/12 - 6:15 AM
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My sister-in-law, a Whaler nut for years, got an Outrage 18 over the winter. It has an older Honda 150, which is a fairly heavy motor, and so as part of the deal she had the yard move the battery up under the console, and they also installed a bilge pump for her. Everything was working fine, except over the weekend she filled up with gas, and then when she went to put the mooring cover on, she noticed the bilge was filling and being pumped out on about a 2 minute cycle as if there were a major leak. She replaced the plug on the bilge drain, and there was no difference, so she asked me to come out and take a look.
After thinking about it a bit, and not seeing any obvious water coming in around the plug, I had a thought - sure enough, the bright lad who installed the bilge pump had led the discharge hose over the transom, and then screwed in a couple of clips to hold the hose down along the transom next to the motor. A bit far down, as you might have guessed - with the full tank, the hose was acting as a siphon and bringing the water right back in after the pump shut off. It wouldn't have actually sunk, being a Whaler, but it sure would have run the battery down.
So the moral of the story is that bilge pump discharges need to be above the waterline - in fact, well above is a good idea. For my sister-in-law's boat, a quick pruning of the discharge hose to the top of the transom and all is well.
But then she ended up with a question, that I don't know how to answer - this bilge pump seems to work on a time cycle rather than with a float switch. It starts up every couple of minutes, and then shuts right off again if there is no water being pumped. Is there a concern about running the battery down with this arrangement?
Tim
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| tom blinstrub |
Posted on 05/29/12 - 6:50 AM
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I would not worry about battery drain unless you went away for a month. I have left mine for over a week several times and the battery seemed fine. One thing about those pumps is if you pull the boat out of the water make sure to disconnect the pump or it will be damaged from cycling while dry. I had it happen twice when I pulled the boat thinking I was going to put it back right away and did not. The sump was dry and the pump kept cycling and weeks later when I launched the automatic function no longer worked.
I know someone who had his 38 ft lobster boat sink because he left the washdown hose over the side of the boat.
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| DennisVollrath |
Posted on 05/29/12 - 6:59 AM
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Tim,
For the 500GPH model, the specification states that the checking mode is 0.2AH/day, which I believe works out to be about 1.25A per cycle for the 1sec it is on every 2.5min. I think the concern is rather small if the boat is not left un-run for many weeks on end.
This is assuming that no water is found during the check mode. If there is, the draw is 1.9A-2.5A for the duration of the pumping.
Dennis
1985 Outrage 18 with Suzuki DF140A |
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| kamie |
Posted on 05/29/12 - 7:02 AM
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Tim,
There are two different types of bilge pumps, the ones that cycle on a set schedule and the ones that work via float switch and only turn on when there is water to remove. Sounds like the former was installed, and yes you should worry about battery discharge. I prefer the latter type with a float but I also turn off the bilge and pull the plugs if I leave the boat slipped or get a solar trickle charger if you must run the bilge pump.
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| gusgus |
Posted on 05/29/12 - 10:07 AM
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I would not have a cycling pump in a boat. Why would anyone need it unless you have a consistently and constantly leaking boat?
1987 Outrage 18 W/150 Merc and 8 Honda |
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| tom blinstrub |
Posted on 05/29/12 - 10:32 AM
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A lot of large commercial boats run those little continuos cycleing pumps along with larger pumps with float switches because commercial fishing boats sometimes have a lot if crap floating around in the bilge that can jamb a float switch. Not that my Commercil fishing Whaler has crap floating around in the bilge. Not
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| tedious |
Posted on 05/29/12 - 10:49 AM
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I think it's just a simpler, cheaper setup compared to one using a float switch - and it's self-contained. But I agree, a float switch makes more sense - why run the motor at all when you don't need to.
I visited the Rule pumps site, and the manual clearly indicated that if the pump outlet was less than 12 inches above the normal water line, you should have an anti-siphon loop, with vent in it. Interestingly, it also said that with these self-contained, timed pumps, you must run the discharge line vertically - I assume that if it's all horizontal, the pump doesn't feel enough resistance and shuts off even though the bilge is filling up.
The Rule site also said that running the pump dry is not a problem - but I'd still unhook it completely if out of the water for a while.
Tim
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| DennisVollrath |
Posted on 05/29/12 - 10:50 AM
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gusgus wrote:
I would not have a cycling pump in a boat. Why would anyone need it unless you have a consistently and constantly leaking boat?
Hi Gus,
Rain is one event that come to mind, if you don't cover the boat.
Electronics or switches can both fail, but my interpretation of the numbers leads me to believe the working draw of an automatic pump should be pretty benign. I have a group 24 battery from West in my boat, and its capacity is listed as 54Ah and 480CCA. Assuming I cut that capacity in half for age or safety margin, that leaves 27Ah. If I need a 480A *10sec crank to start my engine, this is 1.33Ah. Rounding up to 2Ah leaves you 25aH to run the bilge pump. At 0.2Ah/day, this lets you run the pump in check mode for 17 weeks and still lets you start the motor with margin.
This is based upon a perhaps tenuous understanding of battery specs, so real world experience is welcome.
Thanks.
Dennis
1985 Outrage 18 with Suzuki DF140A |
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| gusgus |
Posted on 05/29/12 - 11:11 AM
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Dennis, the trouble with your analogy is eliminating the current draw every-time the motor starts. Start up is roughly (rule of thum 3 times the operating rate. That is unless it is loaded (water in the bilge) and it can go as high as (again rule of thum 5 times the operating rate. If the pump needs to cycle then your calculations are seriously out in the stratosphere. There is also the rate never written on the motor plate, for least efficient period of power draw. That would be when cold. The bearings are cold, the grease is cold and the entire package is inefficient. Most experts agree that most electrical motors use 2 times more power until warmed up, then begin to cruise as warmth and load equalize with the power available.
I am a no parasitic users kind of guy for my boats, cars, motorcycles or snowmobiles. When they are turned off they don't consume or excrete. However I have a float switch on my bilge pump and will install an off switch there too. (refit and rewire in progress)
1987 Outrage 18 W/150 Merc and 8 Honda |
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| DennisVollrath |
Posted on 05/29/12 - 11:40 AM
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Hi Gus,
The .2Ah / day came from the manufacturer's spec. I completely agree with your notion that motor start-up currents exceed steady state by several times. I just think that the .2Ah/day is measured by Rule and already accounts for that. It is a pretty meaningless figure if not.That being said, if I installed one I'd probably check up on it more often until I got comfortable with the theory matching the reality.
As you point out, if there is water to be pumped, then the draws are much more. But this would be the case with either style of pump, and just tells me that if you have a leak or it rains a lot, you'd better check on your boat more often.
Thanks.
Dennis
1985 Outrage 18 with Suzuki DF140A |
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| Finnegan |
Posted on 05/29/12 - 1:24 PM
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I have a lot of experience with the Rule Automatic "computer chip" pumps. They are an excellent product when INSTALLED CORRECTLY AND FOR THE PROPER APPLICATION. They are compact and easy to install. For a boat with a small sump, like a Montauk or smaller, they are a must.
First of all, they MUST be installed with an over-riding on-off switch, so you can turn off the cycling when not needed, which is most of the time when you are using the boat, or when it is on the trailer in storage.
A week of on-off cycling when the boat is docked or moored is not a problem, but for periods of non-use longer than that, I would not install one. In those situations, the float switch activated pump is the proper solution. This is what Whaler installed as optional factory equipment in all of the second generation boats, not knowing in advance how the boat whould be used.
I have an 1100 GPM Auto pump installed in my 18 Outrage, and it works fine, although my boat is trailer stored indoors.
I also install the discharge hose over the transom, using the smooth walled premium hose in black. I bundle it up with the engine rigging and it does not show, and usually terminate it with a plastic 90 degree elbow to discharge the water down and away from the boat. You can see it here in this Montauk photo:
http://smg.photobucket.com/albums/v42...ic0013.jpg
There is no need to drill holes on the transom to secure the hose. It sounds like the work on the boat in question was by an incompetent!
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| tothemax |
Posted on 05/29/12 - 2:26 PM
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If you have a battery switch select one battery and install a simple $30 solar panel - they make them that plug into a lighter connection. It's a quick easy solution and your other battery stays isolated and fully charged.
I have power at my slip so I installed an inexpensive B&D 12v trickle charger. Works great. I run two bilge pumps, one in the cable tunnel well (automatic) and the other in the transom well - with a float switch.
This year I replaced my old rules with these low profile Whale models
http://www.whalepumps.com/marine/prod...art-Family
Edited by tothemax on 05/29/12 - 2:36 PM
1987 Guardian 18 \ 1987 Evinrude 150 |
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| DennisVollrath |
Posted on 08/14/12 - 9:59 AM
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DennisVollrath wrote:
Hi Gus,
The .2Ah / day came from the manufacturer's spec. I completely agree with your notion that motor start-up currents exceed steady state by several times. I just think that the .2Ah/day is measured by Rule and already accounts for that. It is a pretty meaningless figure if not.That being said, if I installed one I'd probably check up on it more often until I got comfortable with the theory matching the reality.
As you point out, if there is water to be pumped, then the draws are much more. But this would be the case with either style of pump, and just tells me that if you have a leak or it rains a lot, you'd better check on your boat more often.
Thanks.
Dennis
Just for a short anecdotal follow-up, I left my boat for 20 days with this automatic pump on recently. No rain that I am aware of. The motor started right up, and the charging voltage of over 14V suggests the battery was still near full charge. This is an older group 24 West Marine battery that came with the boat when I bought it a year ago.
There was still enough charge to perform a dozen or more start attempts while I was drifting in the sound after my fuel line became disconnected, but that is another story.
I am gaining more confidence in this device.
Dennis
1985 Outrage 18 with Suzuki DF140A |
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| gusgus |
Posted on 08/14/12 - 11:54 AM
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Hey Dennis,
That is good news. My pump got it's first test out last week. I found the drain plug out the pump was trying to pump the Puget Sound out of the bilge. I had to laugh, because with a plug installed it was without a job to do.
I worry about my batteries and their life length. So this was my thought when stating I would never have a cyclic pump.
Was your boat moored or trailered?
1987 Outrage 18 W/150 Merc and 8 Honda |
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| tothemax |
Posted on 08/14/12 - 12:00 PM
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I installed a small B&D trickle charger - it took 10 minutes to install and I plan to alternate between batteries each week. Rain is the culprit here and I keep my drains plugged at the dock since they are just under water at rest.
One other option is a small solar charger - the B&D trickle charger was $15 at Home Depot. It comes with clamps, eye rings, and a lighter attachment.
1987 Guardian 18 \ 1987 Evinrude 150 |
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| DennisVollrath |
Posted on 08/14/12 - 12:09 PM
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gusgus wrote:
Hey Dennis,
That is good news. My pump got it's first test out last week. I found the drain plug out the pump was trying to pump the Puget Sound out of the bilge. I had to laugh, because with a plug installed it was without a job to do.
I worry about my batteries and their life length. So this was my thought when stating I would never have a cyclic pump.
Was your boat moored or trailered?
Gus,
I keep the boat moored at a marina on Orcas Island. If I was always trailering it, I'd be less inclined to want a bilge pump. I really use it to evacuate the wash down water after crabbing.
Dennis
1985 Outrage 18 with Suzuki DF140A |
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