Suggestions for small bilge pump

[BrianSmith]

Over a year ago, I installed a Whale Supersub Smart 650 bilge pump in my main bilge. It doesn't use a float switch - it has integrated water detection. It's suppose to pump out all but about 1/3" of water. Sounded perfect for my needs. I installed it next to a Rule 3700 with an external float switch, the idea being that the Whale would do all the work of removing water from my not-so-dripless shaft, and the Rule would be used only in the event of some significant unexpected water coming in.

But the Whale has been a major disappointment. It airlocks constantly - the pump runs and runs, and no water is moved, even when the pump is totally submerged. Also, once the pump detects water and starts running, it never shuts off even after it has pumped out all the water it can. (I get it pumping by shaking it vigorously back and forth, which lets the air out of the very inadequate one-way air vent, which temporarily alleviates the airlock.)

I've had two of the Whales, and they've both done the same thing with the airlock - I think it's a serious design flaw that I can't work around. So I want to replace it, and I'm looking for recommendations.

1. Pumping capacity doesn't need to be much - there should never be more than a few gallons of water (if that) in the bilge before this small pump comes on.
2. Must have 3/4" outlet - replacing the hose to it would be a REAL hassle, and I don't want to do it.
3. It has to have integrate water detection - either an internal float switch, or "smart" water detection without a float switch. I simply don't have physical space for anything with an external float switch.

Does anyone have a recommendation for a bilge pump that would meet my needs? I would prefer to hear from people with actual experience with the pump they recommend. (Or DON'T recommend - if you've tried something that didn't work, let me know, please.)

 

[rslifkin]

I've got that same Whale pump aboard. There's an easy fix for the air lock problem: remove the stupid check valve. It comes with both the check valve and an o-ring for the fitting. With the check valve removed, you get a little back flow, so it leaves a little more water behind, but if your hose routing is good, it shouldn't be a lot. More importantly, with the check valve removed, it works reliably, doesn't airlock, and it moves more water too.



As far as shutting off, it runs for something like 20 seconds after the sensor stops seeing water to make sure it's got it all. But it should shut off after that time delay.

 

[psneeld]

Built this system that someone on TF linked awhile back...


Works like a charm.....because I had many of the parts aboard...cost me less than $50.


https://lifeempirically.com/2018/03/12/build-your-own-diy-arid-bilge-or-dry-bilge-system/

 

[caltexflanc]

I installed one of those low profile Whales and it worked superbly for years. You definitely don't want the check valve, and make sure the hose doesn't dip before heading uphill. Perhaps a picture of your installation would help us diagnose the issue better,

 

[BrianSmith]

Thanks for the suggestion on just removing the check valve - I'll remove it right now. I thought maybe it had to be there for it to work, but it makes sense that all it will do is stop pumping water at a deeper depth, when it starts sucking air in through the little hole.

The non-stop running was happening because of a lot of dirty bilge build-up on the sensor end. Once I cleaned it, it stopped running when not in water. So that's something!

But with the check valve removed to solve the airlocking problem, it leaves well over an inch of water. A far cry from the 1/3" advertised for the pump.

I'll keep looking for a better solution.

 

[Comodave]

I bought a Dry Bilge System that is supposed to get almost all of the water. Have not installed it yet so not sure how well it works. Google dry bilge.

 

[rslifkin]

You might be able to reduce the back-flow after shutoff without the check valve. If you can adjust the hose routing, have it go straight up from the pump as much as possible, then start to go down from there. The less distance you have on the pump side of the high point, the less back-flow you'll get.

Without the check valve it still pumps the water down until the bottom of the strainer starts sucking air, it'll just get some back-flow from the hose draining after it shuts off.

For the most part, no standard bilge pump is going to get the bilge dryer than 3/4" to 1" of water (depending on hose routing) on a reliable basis. A diaphragm pump with a good pickup can probably get you down to 1/2" or less, maybe 1/4" if you really get it right. If you want better than that, you'll need one of the vacuum type dry bilge systems.

 

[HopCar]

The excess water left in the bilge is the water that was in the hose when the pump shut off.
You can reduce this by using a smaller ID hose. Get hose with an OD of 3/4 inch and use short pieces of 3/4” ID hose to connect it to the pump and thru-hull. It will reduce the pump capacity but you’re not worried about that.

If you want to get rid of all the water you’ll need to go to a diaphragm pump mounted out of the bilge.

 

[psneeld]

The DIY "dry bilge" system I linked above runs for 2 min in the morning, 1 min at 1400 and 1 min at 2000.


The last 2 are often not necessary but on auto for when rain or larger amounts of water accumulate.


Otherwise the tiny hose embedded in the sponge literally gets all the standing water out and the bilge air dries by the next day if no new water get in.


Now my regular bilge pumps never run and the sensors don't get dirty.

 

[BrianSmith]

All very good points - thanks, everyone. After reading considering them all, I think I will stick with the Whale, without the check valve, and ignore the fact that it's *advertised* to get all but 1/3" of water. What's the difference, really, between 1/3" and 1 1/2" in a bilge that's a foot deep and only about 18" long and 10" wide? (The difference is certainly not even close to a gallon.)

This bilge will never be totally dry for very long, as that's where my watermaker product water goes until it's good enough to route into the fresh water tank. I do this for a number of reasons, and I'm not likely to change any time soon, so let's leave it at that, shall we?

BTW, my question and your answers DID help with one major issue - solving the airlock problem. So it was certainly worth it! Thanks!

 

[FF]

For those that want a dry bilge with no power draw , obtain any large auto fuel pump, that bolts to the block and is operated by a lobe on the camshaft.

Install it on a raised wooden base with the operating lever pointing down .

Extend the lever with a piece of angle iron and place a lead lump in the end.

AS the boat rocks a table spoon of water will be pumped to a sink or other drain that is always open.

Even with sea water the pump lasts a year or two.

 

[Barking Sands]

Here is a link to a video I just made today outlining the basics of the DIY dry bilge pump. Using a timer instead of a float will also work for you. Many of these timers can start and stop the pump up to 14 times a day for as long or as little as you want. And because it is a diaphragm pump there is no worry on running dry. So you could just set it to run 4 times a day for 5 minutes each time or whatever schedule is likely to keep your bilge clear,
https://youtu.be/KkRvJpzo8CQ