# Questions about installing a second bilge pump



## DavidT (Apr 25, 2008)

I've been wanting to install a second bilge pump and i was wondering how yall have done it. Do you Y both bilge hoses to the 1 thru hull exit? or do you drill and make a new exit? thanks


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## angus_cow_doctor (Apr 13, 2009)

there are 2 exits on my boat. one pump is mounted slightly higher than the other so they don't compete with each other.


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## jim t (Sep 30, 2007)

I suppose you could put one way check valves just down line of each bilge pump and use a t-fitting to your single thru hull(you'd need a check valve for each pump or the waste water pumping from one would pour back into the bilge through the second pump).

For a true back-up and separate system use a second through hull. It's not tough to do. I recommend a metal thru hull fitting rather than the plastic. depending on how tight your hose is it can apply side pressure to the thru hull fitting and eventually break a plastic one.

A second thru hull is preferred for sure though.

Good Luck,

Jim


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## DavidT (Apr 25, 2008)

not to disagree with your knowledge but i hear that you're not suppose to put valves in the hose because it slows down the flow a lot.


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## jim t (Sep 30, 2007)

> *FO' REEL (8/19/2009)*not to disagree with your knowledge but i hear that you're not suppose to put valves in the hose because it slows down the flow a lot.


Sounds good to me... I wouldn't put them in, I ran aseparate thru hull for each of my 3 bilge pumps. I think you gave agood reason to do the extra thru hull.:letsdrink:letsdrink:letsdrink

If you put two pumps on the same hose a lot of the water would simplybackflow to the bilge when one pump runsand the other does not. That's why check valves would be necessary if you wanted to use a single thru hull.

Jim


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## Patriot (Jun 4, 2009)

ABYC Standard for pumps/discharge is 1 discharge for 1 pump. No doubling up. Can run them electrically together for simultaneous operation.

Hope this helps.


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## Sequoiha (Sep 28, 2007)

Hi Tom, welcome aboard, glad to have another professional with good advice on the forum,,,,


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## Patriot (Jun 4, 2009)

Thanks Kenny!!! You still the best!


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## DavidT (Apr 25, 2008)

so i can tap into the existing wires for the new pump? or will i have to run separate wires for both? how hard to make a new bilge exit hole? im sure i can just drill a fit the new thru hull fitting and throw some sealant around it, run the hose, and wire the pump/float and i should be good right?


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## Tuna Man (Oct 2, 2007)

My boat came with (1) one bilge pump..didn't take me long to add another (automatic) and a separate discharge. I had it easy on the instillation of the discharge. Some boats will be tougher. I would NEVER think of running two on one discharge, even with a check valve. FYI if a check valve is ever needed, a washing machine/dish washercheck valve makes for a great one...they are made of nylon and has a free floating ball in them and you can get them free. I used one on my bait well instillation as I have a bilge pump mounted on the outside of the transom for fresh water, to help out with the head lift.


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## Telum Pisces (Sep 27, 2007)

> *FO' REEL (8/20/2009)*so i can tap into the existing wires for the new pump? or will i have to run separate wires for both? how hard to make a new bilge exit hole? im sure i can just drill a fit the new thru hull fitting and throw some sealant around it, run the hose, and wire the pump/float and i should be good right?


It is not hard at all. Here is what I did after my boat almost sunk with a single 500 GPH bildge pump. I now have 2 1500 GPH bildge pumps in my 19 foot boat.:letsdrink

Electrically, I have one on a toggle switch up front. It is manual in operation. The second pump is wired directly to the batter with a float switch in between. This makes this bildge pump fully automatic. So if the automatic pump kicks on and is not enough, I can switch on the other one manually.

Making the extra thru hull is easy as cutting a hole in any wood. Get the proper hoses and a thru hull fitting that matches. I cut the hole on the opposite side of the boat from the original one. I used a hole saw to match the necessary hole and went to town. Used 5200 to seal the wood inside and out. I put a coating on the exposed wood in the hole before inserting the thru hull as well. 

Attach all hoses and make the electrical connections and your good to go. Nothing to it.


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## DavidT (Apr 25, 2008)

> *Telum Piscis (8/20/2009)*
> 
> 
> > *FO' REEL (8/20/2009)*so i can tap into the existing wires for the new pump? or will i have to run separate wires for both? how hard to make a new bilge exit hole? im sure i can just drill a fit the new thru hull fitting and throw some sealant around it, run the hose, and wire the pump/float and i should be good right?
> ...




This is just about exactly what i want to do. add 2 1500 pumps one on a manual switch and 1 on auto just incase the dumb float gets stuck or something.


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## spiderjohn (Feb 3, 2008)

Don't tie to same electrical wiring unless sized accordingly which means the wire would be oversized for one pump operation which would also mean fuses would be oversized and would lead to a potential to burn out both pumps. Pull separate wiring for each. Otherwise be ready for a big headache when the wiring acts up.


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## -=Desperado=- (Jun 19, 2009)

> *spiderjohn (11/27/2009)*Don't tie to same electrical wiring unless sized accordingly which means the wire would be oversized for one pump operation which would also mean fuses would be oversized and would lead to a potential to burn out both pumps. Pull separate wiring for each. Otherwise be ready for a big headache when the wiring acts up.


You can run 2 guage or 14 to a bilge pump its all 12 volt so nothing is going to burn up.If the fuse is to large to match the wire than a potential fire could result but not gonna burn up the pump.Personally i would run different wires,,different switches,different batteries when running a back up bilge.That way you know your covered when 1 electrical syste craps out but you did not say if you had twin engines or not.If both bilges are wired into the same switch and the switch takes a dump than both bilges will be useless.If the hose on both bilges gets a crack than your down to no bilge.No point in having a backup unless its completely stand alone.I have 5 bilges on my boat and there all independent and stand alone with all 1 way valves .check your hoses once a year and electrical connections.Nothing worse than being 50 miles out and taking on ore water than your getting rid of.


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## spiderjohn (Feb 3, 2008)

I was referring to running larger size wire which would be necessary to operate two pumps at once. If you do that, the fuse will be sized accordingly for two pump operation and to the larger wire. In that situation, if one pump fails it could lock its rotor and allow high inrush current to flow for an extended period which the fuses may not catch until the pump itself is heated and burns up. This happens on bilge pumps with float switches when it sticks and the pump is locked up for some reason. Only one pump draws current through a wiring system sized to run two pumps but the current is higher than the pump can withstand. With separate pulls, each circuit is sized for the single pump load so if one locks up and pulls high current, the fuse is sized to protect the pump and blows before too much heat build up. Last post is correct that oversized wiring alone is actually good if the fuse is sized to the load and not the wire. Most pumps tell you what size fuse to use.


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