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s/v Tiger Lily
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Discussion Starter #1
I have two bilge pumps in the center of my boat (from the original owner) controlled by two switches in my galley. One runs immediately when switched on. The other is a float-switch type that is meant to be left switched on.

- Why not just install two pumps with a float switch?

- Is there a reason not to get the highest GPH that you can find? I've seen 4000+ GPH. Why not put two 4000 GPH side by side both with float switches?

- The bilge pumps always seem to leave about an inch of stinkwater unpumped? Is that just because the filters need to be cleaned? Or is that typical?
 

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There is usually water in the discharge hose which runs back down into the bilge after the float switch turns the pump off... depending on how long the hose is and how it is run. Running the pump on the manual switch may get this lower, but it's virtually impossible to get everything out (though I've done it with a Shop-Vac in an otherwise dry boat).

Having a second pump is not a bad idea. One approach would be to install a float switch on the second pump but locate it higher than the first, so that one pump would take care of "normal" seepage (wherever it comes from) and the second would kick in if there was more water than normal or the first pump/switch failed.

I've often thought of doing this on my boat (where the primary factory pump is, unfortunately, a "shower sump" pump), but the problem is drilling out the ribs to run that second discharge hose.

Hope this sort of answers your question.
 

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David,

Easy question first: If you've got a centrifugal pump (like a Rule), then yes, it is quite typical for the bilge to never get completely emptied. What happens is that all the water in the discharge hose from the pump up to your anti-siphon loop will drain back into the boat when the pump is turned or cycles off. Some people install check-valves in the hose run to keep this backflow from happening -- please don't do it! There have been many threads discussion this here on SN; do a search and read on.

Getting a little more complicated, now...

A common set up for multiple pumps is for one high capacity pump on a float switch, paired with a small capacity pump that has either a manual or dual ("manual" & "auto") switch. The reason is that the smaller pump will typically have a much smaller hose bore (like 3/4") as opposed to a high capacity pump (which will normally have a 1-1/8" to 1-1/2" hose.) The smaller hose will hold less water in the run up to the anti-siphon loop, and thus you'll have less water flowing back into the bilge when the pump stops.

If you go elect to go this route, make sure you mount the float switch for the larger pump higher in your bilge than the backflow water level from the first pump.

As far as switches go, I actually prefer to have dual function switches; if your float switch fails, you can always bypass it at the selector switch by simply flipping it from auto to manual.
 

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One theory is that automatic pumps can actually sink a boat.
Let's say you have a stuffing box that starts to leak.
You don't notice and your automatic pump takes care of it for you.
This goes on for months and gets worse and worse.
You might notice that the battery seems a little down for one evening sail but don't think much of it.

You go away for a weekend. The leak gets much worse.
The pump goes on and stays on. The battery goes dead.
The boat sinks.

Some people solve this problem with a cycle counter others by having the lowest pump manual.
So every time you board the boat you know how much water it is taking on.
If it changes you know you have to investigate.

Just a thought, lots of people have fully automatic pumps and like it that way.
Everyone worries about different things.
 
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Two pumps, one higher than the other, both on auto. Another float switch connected to a LOUD alarm that will trip before the second pump activates. Alarm should sound in cockpit too. Gets your attention while sailing and your neighbor's while you're away.
 

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I have a two pumps

One low that does all the work on battery A

One high that never gets wet on battery B

One good size solar panel so nothing goes dead :)

It still did NOT STOP the boat next door from putting there bow sprite through the cabin top SO you can only worry about so many things and just try and keep the systems in good shape ;)

When i take my boat sailing i can here the pumps if they go on and it takes 2 minutes a week to check the oil and give any leaks and eyeball
 

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I have two pumps. One is a typical marine bilge pump with a float switch. It is on it's own electrical buss which i can leave on with the batteries in off to other house loads. The other is a basic (an inexpensive) Sears AC sump pump with it's own float switch (above the DC pump's) that runs direct from AC shore power. I figure that the latter gives me a very high capacity back-up which will run if my DC system some how fails). You can get a counter that tells you total bilge pump run time to track the problem of a chronic leak.
 

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My main bilge pump was wired to run automatically without going through my panel. It was also wired to be manually controlled. I'd recommend this arrangement, rather than just setting it up to only only automatically.

Why? Because your automatic switch might fail. I had a brand new Jabsco pneumatic switch fail the first time it was called to duty during a freak event associated with a 3 day-long Northeaster. It didn't sink the boat, but it did float my floorboards before I went to check on the boat. What if it were a more serious situation? Assuming you were on scene, you'd want to have another option to turn the bilge pump on. I do have a manual pump installed but that is only for extreme backup.

BTW, I never got a response from Jabsco on a warranty claim, not that would I trust their Chinese-made switch again. I replaced it with a Johnson Ultima switch that can be easily tested.
 

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A slow leak will first empty the battery via your lower bilge pump, and leave no power or alarm or second pump.

Two pumps, one higher than the other, both on auto. Another float switch connected to a LOUD alarm that will trip before the second pump activates. Alarm should sound in cockpit too. Gets your attention while sailing and your neighbor's while you're away.
 

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A slow leak will first empty the battery via your lower bilge pump, and leave no power or alarm or second pump.
Fair point on a mooring, if your solar/wind generator can't keep up. Not an issue at a slip.

My main bilge also had an alarm that would sound if it ran continuously for more than a few seconds. The false alarms were shortening my life. I had to disconnect it. Good idea though.
 

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s/v Tiger Lily
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Discussion Starter #12
(OP) I am on a mooring ... I need to examine it in more detail, but I think that my two bilges bypass my DC selector switch (1-2-Both). I'm not sure if they are separated by battery bank ... they could be. The reason I assume that they bypass is that I usually leave my switch on OFF ... and the bilges still run. Is my thinking correct?

What about capacity? Is there any reason not to get the highest capacity that my budget allows?
 

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(OP)....What about capacity? Is there any reason not to get the highest capacity that my budget allows?
Not really, but there are limiters. The really high gph units will require larger diameter hose, so you'll need the right thru hull for them. They will burn more juice too, so be sure you have the right battery capacity too. One of the best ways to improve pump flow is to have smooth bore hoses (huge difference). While the outlet needs to be above the waterline, preferably while heeled as well, the higher the pump needs to lift the water, the less efficient it will be.
 
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s/v Black Prince
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After a few scares with the boat taking on water...one while sailing and another at the dock (both because of human error and all the stars lining up to result in emergency) I reworked my bilge to maximize GPH as follows:

First, my main bilge pump is and remains a Rule 3000 GPH on a separate float switch, with a 3/4 hose, and wired directly to house batteries using the standard Manual, Auto, Off switch.
Next, I saw that my manual cockpit bilge pump had a 1 1/2 hose running to the bilge. So I disconnected the hose, put a Y-connection in a cockpit drain hose that runs under my cockpit and drains out the hull, and connected the 1 1/2 hose that was connected to my cockpit manual pump to the Y-connection. Then I connected a Rule 4,500 GPH pump to the other end of that larger hose in my bilge, but I mounted the pump on a fiberglass base so that it sits about 5 inches off the bilge floor (that way it doesn't sit in bilge water at any time). Instead of using another float switch, I connected the hi capacity pump to a electronic sensor switch that I mounted about half way up the side wall in the bilge. This way, the hi capacity pump is only triggered in emergency situation where the water infiltration to too much for main bilge to handle, or the main bilge fails. This configuration also saves my emergency hi capacity pump from doing the small stuff and using power except when really needed.
 

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s/v Black Prince
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IMHO, any bilge system also should have a counter, to show you small problems before they get big, and audible alarm.
One human error incident involved water pipe bursting, mistakenly leaving water pressure on when sailing single-handed, and the main bilge switch turne off. As I was leaving boat on dock, I heard noise of water running and could not believe the noise was coming from my boat because I new all power was off. Turns out it was before I finished hooking up my emergency hi capacity hose...but I had the pump and electronic switch installed. So the electronic switch was triggered because the water had risen to mid-level since the main bilge was off, and the hi capacity bilge was just blowing the water around in the bilge which was the noise I heard....now that would have run my batteries to 0 since the pump would have never shut off because water level was not being lowered.
Anyway, very good idea to pay close attention to your bilge BEFORE the stars line up to create an emergency.
 

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s/v Tiger Lily
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Discussion Starter #17
Stiffwind,

I wasn't aware that you shouldn't have pressurized water on under sail? Is that a general rule, or with your system in particular.

Does your bilge counter count the number of times that the unit comes on or the volume of water it's pumped out?
 

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Puget Sound Pounder
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Here is what I am thinking on the subject. I essentially learned this by going through all the bilge threads on SN. Wow, incredible source of info. I took the best ideas so I came up with a plan.

My current system really sucks, a single Rule centrifugal with with check valve three feet from the pump. And there is a good twenty foot run to the stern. It does have a good high position in the line for anti siphon though.

A. New primary bilge. A Whale diaphragm type with a small strainer in the deepest part of the bilge and the pump located three feet away. 300 GPH. It has an integrated float switch and check valve at the strainer. 3/4" Bilge line to the transom.

B. The current Rule will become secondary. Mounted about six inches above the strainer of the new primary pump. Remove the check valve from the Rule bilge hose. 1100 GPH

C. Add a tertiary 2000 GPH near the engine compartment. Johnson centrifugal 2000. No check valve. Water Witch switch with an outside alarm. 1.5" bilge line to the transom.

I do have a manual system in place currently, an important fact.

It's amazing what you can learn on this site.
 

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General rule is to shut off the fresh water pressure switch when underway. If a hose breaks while you are at anchor, you will most likely hear the bilge pump running and be able to save your water supply. If it breaks underway, you may be out of FW before you realize. Depending on where you are cruising, that may be either an inconvenience or a serious problem.

If we need water underway, we turn it on, then back off again.
 
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