Best Bilge Pump?

Timm R Oday25 · Feb 4, 2020

I believe your problem may simply be one of routing. The hose from the bilge pump should be higher than the outlet . Some folks have a loop in there system. I was advised early on no to use a check valve as they may stick in the closed position.

Justin_NSA · Feb 4, 2020

What Timm said

dLj · Feb 4, 2020

I don't think these pumps prevent backflow. You'd have to put a one way valve in your line if you really have to do that. I put a brand new bilge pump in my boat a couple years ago, it does not prevent backflow. I would not be a fan of putting a one-way valve in, by the way. I'd rather move the location of the bilge output or change the piping although I realize that's a lot more work... But it's your boat...

dj

NYSail · Feb 4, 2020

If your exit thru hull goes below water at any time the solution is to add enough hose to make a loop above the potential water line prior to exit so water cannot get back in when you heal. You must read about what the capacity and "head" the pump is capable of..... Back flow valves are typically not on pumps but are added to the hose after pump. Some people like them, some feel they get clogged with debris from the bilge. I dont have them but my response typically to this is what debris is in your bilge floating around?? Time to clean!!

Good Luck

FastOlson · Feb 4, 2020

Not a question of newness, but rather basic design. If you have the common inexpensive centrifugal ("Rule") pump, they will back-flood. If you install a check valve, this reduces their already deceptive actual thru-put even more.
Since all of these small-physical-size pumps exist to remove nuisance water and to also give you time to find and plug a larger leak, best to have one that is totally reliable and also has GPM specs that are actually achievable in the real world.
The Jabsco 37202-2012 series (and similar) will do this. Our boat was factory equipped with two of them. Not cheap, but expect a lifetime of use and zero back flooding.
Given the age of your boat, it's time to run new hoses anyway and double-check the float switches.

We have replaced only one of these pumps and the other is original from '88. I have run all new hoses a few seasons ago, and replaced the old thru hull fitting with ss. Not difficult work but you will get acquainted with parts of the aft compartments that will tax your ability to reach, and add some swear words to your vocabulary.

dlochner · Feb 4, 2020

As others have said, put a loop in the line. The loop will prevent seawater from entering when the outlet goes below the waterline. The closer the loop is to the pump the less water will back flow from the hose. The typical bilge pump can not pump air so any water that is in the line will drain back into the bilge.

Some of the new Rule pumps have a check valve at the outlet of the pump for this reason. Basically the check valve works like the joker valve in the head. This is the only place to put a check valve unless 2 or more pumps use the same outlet then a check valve is necessary to prevent water being pumped back through the second pump and into the bilge.

Whale makes a nice diaphragm pump with integral check valves. Because it is a diaphragm pump, it can keep the bilge drier and there is little back flow.

Justin_NSA · Feb 4, 2020

PS: my discharge hose had a loop in it but it leaked into the cabin when the pump came on. It replaced the cheap, defective corrugated hose with smooth bore hose. Better durability and less flow resistance.

Calif. Ted · Feb 4, 2020

ABYC standards require bilge discharges to be above the waterline at all angles of heel. Your typical float switch turns on at 3" and off at 3/4" and then any water in the uphill section of hose will drain back to the bilge also. As FastOlson remarked a positive displacement pump such as the Jabsco shouldn't allow backflow freely like a centrifugal pump.

Justin_NSA · Feb 4, 2020

Are you sure your boat doesn't have a loop? Especially if the discharge is so low? Would the builder intentionally violate the standard?

Calif. Ted · Feb 4, 2020

AlastairLC said:
Thanks FastOlson. That item appears to be a shower drain pump. (?)

They are used for that also, mostly they are a positive displacement pump which means it is self priming (pumps air or water) and can be located remotely outside the bilge. A centrifugal pump only works if the impellor is in the water.

dlochner · Feb 4, 2020

AlastairLC said:
Thanks Delochner. Is this the one?
Whale SS5212 Supersub Smart 650 Electric Bilge Pump, Suitable for Use with Fresh or Salt Water, 12V DC, 3.4 Amps, Open Flow Rate of 650 GPH @ 13.6V DC, 16 AWG Wire, ¾-Inch and 1-Inch Hose Connections https://www.amazon.com/dp/B003E1WQU4/ref=cm_sw_r_cp_tai_E.yoEbH6B11HX

No, it is this one, A Whale IC Gulper it is based on the gulper series of pumps. The pump mounts outside of the bilge. It is not inexpensive, but it is robust.

JamesG161 · Feb 4, 2020

dlochner said:
Some of the new Rule pumps have a check valve at the outlet of the pump

BTW Jabsco and Rule pumps are made by the same Company.
Xylem Global Brands | Xylem US

Their Diaphragm pumps need check valves [that are part of the pump] to operate.
Jim...

PS: Corrected for clarification.

Benny17441 · Feb 4, 2020

Chances are that is not the principal source of inflow to your bilge; Water from different sources gets trapped in the hull stringers below the sole and gets released with boat motion. Contributing to this inflow are rain leaks, plumbing leaks, boat wash downs, sea spray, wet bathing suits, fridge and cooler drains, showers...…. You may have noticed that your galley sink drains faster when the boat is underway, there is something about water rushing across a small opening that creates sort of a vacuum which tends to pull water out not in. Any amount that does get in as the boat rights itself should be minimal and insignificant. The use of a check valve is not recommended as they have a high incidence of failure and could obstruct the pump discharge overboard. In the real world the performance of a bilge pump is about 25% of the rated capacity by the manufacturer. They rate the pumps mounted on a bench with no loads, with ideal voltage and cool. The addition of a loop in the discharge hose will further hinder capacity. Some of the electronic pumps that turn on every couple of minutes to sense for water might do a better job of discharging back flow but I do not know of a pump that does not permit any back flow. The only way I know of getting the bilge dry temporarily is with the use of a sponge and bucket. I long ago opted just to clean the bilge a couple of times a year and ignore any small amount of the water that may be present in between.

FastOlson · Feb 4, 2020

AlastairLC said:
Thanks FastOlson. That item appears to be a shower drain pump. (?)

They are commonly used for bilge pumping, bail wells, and shower drains. The maker does not say that, but various vendors may add their own ad copy. I just looked at a weighted ad on Google from Amazon (their sales verbiage should not be given value over the manufacturer's description.)
Here is one of several sites; Jabsco 37202-2012 - Self-priming diaphragm pump 12 volt d.c. / Sink & Shower Drain Pumps / Pumps / Marine / Xylem JabscoShop - Jabsco & Rule Pumps and more - from the experts

Fisheries also sells it and among other uses, specifies it for bilge pumping.