Bilge Pump Advice needed

[roland stockham]

Speaking from experience as I also have a deep bilge (about 3ft to sole) I found that anything less than a 2000g/hr centrifugal pump was useless. The head pressure plus pipe resistance was such that smaller pumps were not able to lift any water effectively. This may be your problem and the solution is a different type of pump that has a high head and small volume at the pickup end.

[CarinaPDX]

The problem is not the switch, it is the water running back into the bilge. A proper check valve immediately after the pump should stop that. By proper I mean like those sold by Whale, not the brass ones found in plumbing stores that can slowly let the water leak back.

The best approach for dewatering is to use a diaphragm pump with a foot valve (check valve built into the pickup strainer). I just bought one of these for exactly the same purpose: https://www.whalepumps.com/marine/pr...dlyID=Bilge-IC

As long as there is even a small amount of water entering the bilge, from drips at the shaft or elsewhere, it will never completely dry out. Get over it...

Greg

[Eder]

My bilge has never had less than 2-3" of water in it...what is the problem?

[jpendoley]

Originally Posted by Eder

My bilge has never had less than 2-3" of water in it...what is the problem?

Some people believe trapped water in the bilge exacerbates or contributes to blistering. I'm less concerned about that then the odor it promotes. I'm trying to eliminate as much ingress as possible and have it as dry as possible as a matter of good boat hygiene and upkeep.

[jpendoley]

Back from the bilge. Seems the problem was the sensor mounting tab is connected internally to the sensor-water hitting the tab can set it off. I raised it a schooch and the pump now works the way it should. However...now the check valve I purchased at the plumbing supply store randomly gets stuck closed. I do think a 1000 GPH pump might be too weak for this application. Have very little faith in this arrangement. thinking a remote mounted diaphragm pump is the way to go.

[Jammer]

Originally Posted by jpendoley

It shuts off then starts back up again and runs continously no matter how little water remains.

Then either you have it wired wrong or it's defective. They aren't supposed to do that.

[DeValency]

Originally Posted by Eder

My bilge has never had less than 2-3" of water in it...what is the problem?

For some reason, I like any water, even a drop to stay out of the boat. My bilges are dry as a bone 🦴

[jpendoley]

Originally Posted by DeValency

For some reason, I like any water, even a drop to stay out of the boat. My bilges are dry as a bone 🦴

Kind of feels like if the bilge is always sloshing with water minor problems can go unnoticed until they are no longer minor. It’s an individual preference of mine
YMMV

[CarlF]

A few ideas:

I've found the water witch switch to not be as reliable as the marketing claims. The only switch I use is the Ultra. Expensive but they never have problems.https://www.ultratef-gel.com/product...nior-2432volt/

The diaphragm pump is a good idea but will still leave you with water in the bilge. The Whale Gulper is the one to get. Be sure to get a strainer on the end of the hose or the hose will clog.

Since the pump you have now is only for nuisance water, you don't really care about GPM. Step the hose down from 3/4" to 1/2" and take out the check valve. There will be much less weight of water in the hose to pump uphill or to run down hill after it turns off. It will still pump enough to do its job.

I've never had a dusty bilge in 40 years of owning cruising boats and it's never caused a problem. If you want to keep humidity down in the boat - ventilation is more important. I mounted a Noctua 12v computer case fan as an exhaust fan for the engine space. It's left on continuously. Draws 1 watt and is almost silent.

[waterman46]

Originally Posted by Jammer

Move the switch an inch higher.

You do not get an award for having a dusty bilge. If you care enough you can vacuum it out with a wet-dry vac before the Bilge Committee arrives for an Inspection.

Great answer. I'm wondering what is the need to have a completely dry bilge when it is very deep anyway.

I installed a Y valve on my shower diaphragm pump, which is manually switched as needed, no float necessary since we don't use a shower sump. The Y valve can be set to make the same pump suck water from the bilge, down to about 1/2 inch. I hardly ever bother.

Seriously, I don't know why boat makers don't add a small sump area of the bilge that is about 4" deeper than the rest, and big enough for a strainer.

[Squanderbucks]

How about a hump in the hose that is close to the pump so that the longer section of the hose is below the hump and the hose portion with the residual water is smaller.

[steve77]

Originally Posted by jpendoley

Back from the bilge. Seems the problem was the sensor mounting tab is connected internally to the sensor-water hitting the tab can set it off. I raised it a schooch and the pump now works the way it should. However...now the check valve I purchased at the plumbing supply store randomly gets stuck closed. I do think a 1000 GPH pump might be too weak for this application. Have very little faith in this arrangement. thinking a remote mounted diaphragm pump is the way to go.

I think that the centrifugal pump just won't cut it, regardless of the size. To remove the last bits of water, you need a diaphragm pump. A diaphragm pump is a positive displacement pump, and will pump any fluid, including air. Couple that with a strainer such as the one below, and a system to keep the pump running for several seconds after the low set point, and you should get as much water as is physically possible out of your bilge. Your water witch switch would be able to do the latter.

https://www.defender.com/product3.js...4256&id=157440

One last point, you are not trying to remove large quantities of water with this pump. Keep your suction hose fairly small diameter, I'm thinking no more than 3/4 inch. This will also reduce the volume of water that may leak past your check valve and flow back to the bilge.

Cheers!

Steve

[chasmains]

Jpendolay,
I’m a pump engineer by training and profession.
If you use centrifugal pumps anywhere to pump water, install a check valve immediately at the discharge. If you don’t and you pump uphill at all, when the pump stops because of switching functions, the water in the discharge line will run backwards into the sump. That water can be enough to trigger the pump start logic. This will kill batteries in hours.
If you use diaphragm, vane or piston pumps, you won’t have that problem. These pumps have internal valves at the suction and discharge to ensure the flow goes out the discharge port. These pumps can pump water and air so are great for getting everything out of your bilges. But you need a good low profile suction fitting that lies on the very bottom of the bilge surface. And NEVER shut the discharge valve or the pump and maybe your discharge line will rupture or your pump will break.

[MJH]

Originally Posted by jpendoley

I am losing my mind with a bilge pump project-maybe you all can save my sanity. I have a DEEP bilge-like 48" deep. I have a great high capacity water pump that is alarmed and wired to a counter-works fine. I am trying to install a nuisance water pump to remove rain water that enters the bilge via the stowaway mast. Rain runs right down the large mast slot and drains into the bilge. I installed a mast boot, minimally effective and there is always the drip from the stuffing box. Eventually I will buy or make a "dry bilge" diapragm pump and tubing solution to get the last drops, but first I have to get the lower capacity nuisance pump to shut off aft?er it is activated by the water witch sensor.
The nuisance pump has a check valve installed right after the pump to prevent water in the long hose line from draining back after the pump shuts down-seems to work well (kind of clunky-bought from a plumbing supply store but has low resistance which I would think is a prerequisite) BUT the water that remains is enough to trigger resistance on the nuisance pump impeller such that the pump thinks there is enough water to require pumping. I'm talking like a 1/2" of water. Result is the pump cycles on and off continuouisly and would drain the batteries eventually if left it unattended. The pump is a Johnson 1000 GPG pump-had the same problem with a Rule 500 GPH pump. Anybody got a model recommendation that would solve this problem?

I have a similar issue with my boat's 48" bilge. By the time the hose gets to the vented loop it is a six foot lift. With a deep keel you will ALWAYS have water in the hose when the pump turns off due to hose length. So limit the nuisance hose to a 3/4" but put a larger pump to it to insure it gets the water out and a check valve after the pump to stop the residual water from returning to the bilge. Lastly, don't use one of those fully automatic pumps but rather a stand alone float switch with a manual switch...I only use the manual switch on my boat to dry out the bilge as much as possible. My main bilge pump (3700gpm) is set on auto (no check valve) with the nuisance pump on manual.

Good luck.

~ ~ _/) ~ ~ MJH

[EngNate]

As mentioned up the thread, a current-sensing auto pump will work much better for this. These pumps come on momentarily every minute or so and keep running only if water is being pumped. Running the discharge into a shower sump is also a good idea to reduce flowback. The best check valves for bilge are the Boswell (Guzzler pumps). I've seen a lot of issues with the Water Witch sensors, a film of salty water across the electrodes will keep it on. Rainwater is going to wash salt down with it, and if a metal mast it may pick up oxides too on the way down. Jabsco once made an untrasonic bilge switch, its too bad they don't anymore, tat would be the way to go.