second bilge pump

jvbarber00

Cadet
Joined
Apr 7, 2015
Messages
7
I am wanting to add a second bilge pump to my bow rider as a back up. My boat is 18 feet. Should I drill the hole for the second pump on the same side as the current or should i go to the same spot on the other side. What should i use to drill the hole and what sealant should i use.
 

alldodge

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Mar 8, 2009
Messages
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I am wanting to add a second bilge pump to my bow rider as a back up. My boat is 18 feet. Should I drill the hole for the second pump on the same side as the current or should i go to the same spot on the other side. What should i use to drill the hole and what sealant should i use.

Same side or opposite side is no issue, only your preference. Hole saw works best (IMO), drill forward until bit makes it through, then reverse the drill until the larger hole saw makes it through the gelcoat. Once through gelcoat, go forward again and use 3M 5200 sealant.

To add something which you did not ask, is I would not add a backup pump, I would add either a larger pump or another battery to give you longer run time
 

smokeonthewater

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Dec 3, 2009
Messages
9,838
IMHO the pump should always discharge on the same side as the operator sits..... Much better chance of noticing it and thus noticing a problem.
 

Maclin

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May 27, 2007
Messages
6,761
I like that you are adding a second outlet and not tee-ing them together. I prefer the outlet(s) on the driver's side for same reasons as Smoke listed. Ok, only one reason, but I like it...:)
 

UncleWillie

Captain
Joined
Oct 18, 2011
Messages
3,995
If the pumps are different sizes, use the Smaller pump as the Primary, and the Larger one as the Secondary.
You should have Automatic Float Switches on Both Pumps.
And they should be as independent as possible. Separate wiring, fuses, and Batteries.
Small pumps tend to pump out more water as they sit closer to the deck.
If the small pump can not keep up with the flow, the larger one will help greatly.
Adding an Audible Alarm in parallel with the second pump will alert you that you are in real trouble.
 
Last edited:

JoLin

Vice Admiral
Joined
Aug 18, 2007
Messages
5,146
If the pumps are different sizes, use the Smaller pump as the Primary, and the Larger one as the Secondary.
You should have Automatic Float Switches on Both Pumps.
And they should be as independent as possible. Separate wiring, fuses, and Batteries.
Small pumps tend to pump out more water as they sit closer to the deck.
If the small pump can not keep up with the flow, the larger one will help greatly.
Adding an Audible Alarm in parallel with the second pump will alert you that you are in real trouble.

Mount both pumps as close to the bottom of the bilge as possible, BUT mount the float switch for the larger pump a bit higher than the switch for the small one. No point in having them both running unless you need the big pump to join in.
 
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