Dual Bilge Pump Plumbing

[CaliCrabber]

Im replacing the old, nearly useless, bilge pump in my '75 Starcraft Holiday. Think Im going to pick up a Johnson Ultima Combo, 1000GPH. When I bought the boat, the PO threw in a little Attwood 500GPH cartridge bilge pump, in the box, new (thanx for small favors). I was considering installing both in the name of redundancy. The Johnson will be on an on-auto-off switch, as the primary pump. So if I install the attwood, my thought was to wire it through a second, on-off switch, in case of emergency and a failing Johnson. So if I install both pumps, whats the consensus? Two switches? Is this overkill? Or is it pointless adding a smaller pump as my emergency back-up? And if I do install the attwood, can i plump its discharge hose into the Johnson's with a T and a check valve in between the pumps, or would I need to drill a Second hole in the hull for the second discharge? Any and all thoughts, comments and suggestions are appreciated. Thanks iboats!

 

[bruceb58]

If you want true redundancy, you want it to have its own switch, wiring, hoses and discharge. If you want it to be automatic, it needs to have its own float switch set a bit higher than your current one.

 

[CaliCrabber]

Wow...Thanx for the rapid response, Bruce! Ok, That makes complete sense, kinda what I figured. I wasnt going to put the back up pump on a float switch. If the primary fails and I really am in need of the bilge pump, I think Ill flip the switch on the secondary and boogie for the shore. What do you think about using the little attwood for a back up? Better than nothing, or not worth the extra holes and plumbing?

 

[CaliCrabber]

Or does it seem backwards to have a second bilge switch at the helm? Leaving the back up pump on auto with a float switch would save dash space...

 

[bruceb58]

You could have one switch at the helm and make it a double throw switch(just for redundancy). You would still drive each pump off a separate fuse that way.

Just make sure each pump has it's own float switch.

 

[GA_Boater]

I have two. One is dash switch and the second is auto float switch directly to the battery. I have the smaller pump on the auto switch and the larger one on the dash switch.. It works for me.

The plumbing should be kept separate. If you tie the the two outputs with a tee, you two check switches. Trying to discharge both pumps through the same discharge cuts the capacity because only so much water can be pumped unless you increase the size of the thru hull and connecting hose.

 

[Chad Flaugher]

I recognize a perfectionist when I see one. I too am a perfectionist... Settle down cowboy, why do you need two pumps? I'd say fix your leaks first! If you don't have leaks, you don't need a second pump. Just sayn' :yo:

 

[JASinIL2006]

I added a second pump, too. The first is auto with an oh-off switch at the helm. The second is an auto only, on a separate battery, set to go off only if the water level greatly exceeds where the first pump should switch on. I added my second pump because we are docked for several weeks at a time each summer, and relying only on one pump/battery made me nervous. If my boat lived on a trailer all the time, I don't know that I'd bother.

 

[UncleWillie]

Both pumps should be on float switches, manual switches are for backup operation.
If the auto switch were to fail, by the time you notice you need to operate the manual switch, you will be way behind the curve.
A singe, double pole toggle switch, that activates Both pumps is a viable option.

The primary pump should be the smaller pump, as it will be mostly pumping incidental water.
If it fails the larger, seldom used pump takes over.
The smaller pump will also pump the bilge drier, as it will remove water closer to the hull than a larger pump.
If you get into a situation where the second pump is required, The adding, three times the capacity (500-->1500), will be a better option than adding 50% capacity,(1000-->1500).
An audible alarm on the secondary pump will notify you that the is trouble down below before your feet get wet.

 

[CaliCrabber]

Thanks guys! The knowledge pool from the iboats members on this forum is such an invaluable resource. Well, since ive got every bodies attention, any opinions on solid-state vs. mechanical switches?

 

[GA_Boater]

Get one with a mercury switch and magnet. I don't like the solid state (electronic) since it lives in the basement. Just my opinion.

 

[CaliCrabber]

thanx for the tip, GA! ill check those out

 

[airshot]

Well I have two pumps as well, just the thought of safety first. Yep I have an older aluminum boat that does have a couple leaky rivets so my pump does come on a couple times during my fishing trips. My pump is set right on the bottom so If I get more than an inch of water it comes on for a minute. I have one pump connected to each battery and the main pump to the dash panel and the backup pump is fully automatic from the second battery. If you ever have the unfortunate experience of getting a real leak due to striking an object or some other form of bad luck you may well wish you had an extra pump so I do have one just in case!!

 

[CaliCrabber]

I appreciate the input, Airshot. You say your main pump is on a switch at the helm...is it an on/off switch, or an on/auto/off with a float switch at the pump? And do you have two separate discharge ports through the hull, like bruceb58 suggests? How many GPHs are your pumps rated for and what size is your boat? Just trying to get the big picture of how the rest of the iboats fleet operates. Thanx again every body!

-Oh and for any iboaters who feel like chiming in, on the topic of on/off pump switches, are these generally used with bilge alarms? Or do you just periodically flip it on every so often?

 

[airshot]

The main pump is at the helm but also has an automatic float switch which takes over when helm switch is turned off. The other is fully automatic, each has its own discharge port and each runs off separate battery. They are Atwood models with built in floats, had them for a few years without issues. I believe they are 500 or 750 gallon rated. My boat is a 22' StarCraft Islander. And yes on occasion I just flip it on to be sure everything is working, with the boat sitting still and motor not running you can hear the pump if you listen carefully.