Using Your Engine as a Bilge Pump

[off-the-grid]

I just heard this one for the very first time the other day. Someone suggested putting a Y-valve on the engine intake, and running a hose to the bilge, to use it as a pump.

Is this actually a good idea...or was this guy just nuts?

On one hand, it sounds like a genius idea! You're engine is going to pump a hell of a lot more water than any other pump you'll find out there, and for longer, without relying on the electrical system, or risk of draining your batteries.

On the other hand, it sounds like a great way to potentially quickly kill your engine.

[mitiempo]

I don't think it would actually pump that much - look at your exhaust when the engine is running at cruising speed, that's what you would get.

The big issue is all the debris in the bilge passing through the engine or heat exchanger. If a strainer is installed there is less risk of debris but as the strainer restricts flow more risk of overheating the engine.

If trying to plan for a large inflow of water the best solution, besides electric and manual dedicated bilge pumps, would be a crash pump belted to the engine and activated by a clutch.

Or possibly this new product: Fast Flow Emergency Bilge Pump

[callmecrazy]

how much debris is in your bilge? mines pretty empty...

It probably won't pump a whole lot of water, but it's better than nothing The Y (or T) is also useful for flushing the motor out with fresh water, or winterizing.

[mitiempo]

My bilge is pretty clean as well, but I think the original poster was referring to a time when there is damage and the other pumps can't keep up, not as a daily maintenance pump. After there is a foot or so of water in your bilge that is not normally there I think you would be surprised how much debris can show up.

[HopCar]

Take a look at Groco's Safety Seacock and Safety Seacock conversion kits. They are designed to do just that. They also allow you to fresh water flush your engine. As long as the bilge pick up is before the sea strainer you shouldn't damage the impeller with debris from the bilge.
GROCO MARINE PRODUCTS
I've put a pipe T on the intake side of my sea strainer. One side of the T goes to the strainer, one side is hooked to the seacock hose and the third side has a ball valve and hose to the bilge. The ball valve is normally closed. In a flooding emergency I will open the ball valve and close the seacock.

[Celestialsailor]

I've heard of the concept years ago. The idea was "if" you were suffering a catastrophic hull breach that the bilge pumps could not keep up with. I have run my engine on the hard with a 5 gallon bucket of water. It empties in about 30 seconds to a minute. It's not a bad idea really.

[msponer]

These centrifugal pumps that clamp around the prop shaft are interesting, since they pump a lot more than the tiny raw water impeller on an engine:
Fast Flow Emergency Bilge Pump

But do you guys feel it's likely an engine would start with the wiring harness, batteries, or starter solenoid under water? AGM batteries may not mind, but there are still the terminals: do they short out?

I wonder if anyone has taken a 120v AC pump-- some pools are saltwater these days, maybe there's inexpensive mass market pumps for them. Could be plugged into the little Honda generator that many people carry.

[Celestialsailor]

The water would be almost a foot over the floor-boards if it got to the starter. At that point I might be on the radio for help and thinking of plan B.

[JayCall]

Years ago I had a 65' classic wooden motoryacht built in the early fifties, had twin 6V71s, each engine had an auxiliary pump with a manual clutch, plumbed into a manifold with pickup hoses to five different bilge compartments. When the boat was on the hard for a while and the hull planks dried, a lot of water came in for about a day or so until the hull planks swelled back up. Those pumps could really move a lot of water. It is actually a good backup system, you would be amazed how deep water can get around a diesel before it quits once it is running. Basically, as long as the air intake is clear, it will keep on running.

[xymotic]

If you're going to go to all the trouble of a 120v pump and generator to run it, you might as well just have a proper pump rated to handle debris and everything

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[gjordan]

I worked on a 92 foot wood motor yacht for a while, and the GMC 6-110s were equipped with valves and strainers to use them as bilge pumps. At anything above an idle those engines put out a lot of water. A really good idea._____Grant.

[captainbri]

The only way I would use the engine to pump water is to run a pump off the engine then have an electric clutch like an automotive a/c clutch, this could be turned on by a float or manual switch. a hose could be attached to it incase the head or something else is backed up or clogged.

[delmarrey]

I considered putting a electrical clutch operated pump on the front damper pulley of the Yanmar but looking at the maintenance factor I decided against it.

The thing would be spinning a bearing that had no purpose for who knows how long and may even fail before I had used it or maybe while I was using it. So I'll just buy another electric Whale gusher to go along side the manual one.

But I have put in a T in the inlet line w/screen of my 5 gpm washdown pump for the up forward section of the bilge, which does slowly drain into the main bilge. But I figure it can't hurt and nothing wears out in the mean time.

As well I have a 110V submersible (15 gpm) that I keep aboard, either for my own use or if I happen upon a vessel in need. I can use it to help pump out someone else's. I've tested it on the inverter and it does fine as long as I keep the motor charging the batteries.

The problem I see with a Y valve is you do need a screen to keep debris out of the pump. And it would have to be monitored to keep it from running dry, damaging the impeller. Which might compromise the boat even more.

[captainbri]

Originally Posted by delmarrey

I considered putting a electrical clutch operated pump on the front damper pulley of the Yanmar but looking at the maintenance factor I decided against it.

The thing would be spinning a bearing that had no purpose for who knows how long and may even fail before I had used it or maybe while I was using it. So I'll just buy another electric Whale gusher to go along side the manual one.

The engine would go out long before a sealed bearing, In 15 years of wrenching, I have had to replace clutches but never had a bearing failure. I would run the pump with a bracket bolted to the engine this way you will not have balancing issues. plus if all else failed it would be better than using the whale gusher. IMHO Cheers.

[off-the-grid]

Maybe I'll just stick with my original plan of removing the rest of the below water through hulls. And hope the closed cell foam I poured into most of the voids takes care of the rest. Worst case, she should still at least float...just much lower in the water.