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Old 05-04-2013, 01:46   #1
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What do you all think of engine-driven bilge pumps?

Lots of pros and cons...con: they suck in so much water that the pump get clogged easily (would a big strainer work on the intake side, so debris is easy to clean off?); pros: they suck in a lot of water quickly.

Any personal experiences here?
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Old 05-04-2013, 06:04   #2
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Re: What do you all think of engine-driven bilge pumps?

No personal experience. Some additional cons: expensive to purchase, hard/expensive to mount on many boats
A portable gas powered Honda crash pump is also an alternative and probably net less expensive.
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Old 05-04-2013, 06:26   #3
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Re: What do you all think of engine-driven bilge pumps?

I think most boaters are better off with multiple large electric pumps and one or two manual back ups. In my experience in emergency flooding situations it is best having multiple options so that pumping can continue if one is clogged. Electric pumps will keep going for awhile even if the engine is knocked out too.
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Old 05-04-2013, 07:19   #4
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Re: What do you all think of engine-driven bilge pumps?

Engine driven pumps didn't work out so well for the BOUNTY

but really, second Kettlewell's suggestion. Whatever you decide on, have manual backup
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Old 05-04-2013, 09:49   #5
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Re: What do you all think of engine-driven bilge pumps?

I worked on an inspected vessel with 5 watertite compartments.It had an engine driven bilge pump with pipe running to all compartments and a strainer on the end of all. This worked great,but is probably too much for all but the biggest private yachts. A good alternative is to add a tee in your engine raw water intake with a valve and a strainer. In the event of an emergency you can use the raw water pump to dewater the bilge.
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Old 05-04-2013, 12:04   #6
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Re: What do you all think of engine-driven bilge pumps?

There have been several threads concerning using the engine raw water pump with valving to be an emergency pump. I worked on a couple of large motor yachts and one had the manifold system with a separate engine driven pump and one had the T fitting to use the raw water pump. I agree with haw1961 that the manifold system is way too complicated for a small yacht. The T using the raw water pump is somewhat more practical, but requires a really good strum box, or you will have a burned up motor in short order. Electric pumps (several) and manual back ups are probably the easiest solution. You might want to look up the rules for offshore racing? I believe they require a manual pump usable in the cockpit and one usable down below. That makes sense to me. Whatever system you decide on, make sure you have good strum boxes and know how to clean them in a hurry. Good Luck_____Grant.
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Old 05-04-2013, 12:15   #7
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Re: What do you all think of engine-driven bilge pumps?

The downside is if it works well and moves out the water, then your engine could overheat.
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Old 05-04-2013, 16:25   #8
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Re: What do you all think of engine-driven bilge pumps?

The 3/4" intake hose on my raw water pump tells me all I need to know about its capacity. Not much water needs to move thru the system for cooling an auxiliary sailboat. My big electric pump has 1 1/2" hose, 4 times the capacity.

I think the raw water pump idea must have come over from the powerboat world. For sailboats it is nonsense. For a test, close the seacock, pull the intake hose and stick it in a 5 gallon bucket. The bucket lasts a long time, even at high RPM.
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Old 05-04-2013, 16:33   #9
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Re: What do you all think of engine-driven bilge pumps?

Quote:
Originally Posted by haw1961 View Post
I worked on an inspected vessel with 5 watertite compartments.It had an engine driven bilge pump with pipe running to all compartments and a strainer on the end of all. This worked great,but is probably too much for all but the biggest private yachts. A good alternative is to add a tee in your engine raw water intake with a valve and a strainer. In the event of an emergency you can use the raw water pump to dewater the bilge.
We have this with 3 compartments; works well but never used it
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Old 05-04-2013, 16:42   #10
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Re: What do you all think of engine-driven bilge pumps?

For an OMG Holy Sh*t Pump, I would go with a Shaft Driven Pump

Fast Flow Emergency Bilge Pump

Hopefully You would never need it

cheers
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Old 06-04-2013, 06:04   #11
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Re: What do you all think of engine-driven bilge pumps?

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Originally Posted by riggear View Post
For an OMG Holy Sh*t Pump, I would go with a Shaft Driven Pump

Fast Flow Emergency Bilge Pump

Hopefully You would never need it

cheers
Pretty hard to find a place to install on many sailboats. Seems like a lot of wear while continuously running - but I guess they that figured out.
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Old 06-04-2013, 06:19   #12
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Re: What do you all think of engine-driven bilge pumps?

I have a t fitting. Mostly used as it makes pumping anifeeze into the raw water easy. I once used it after a failure of a fitting. I was actually impressed by how much it added to pulling down the level. Beat the hell out of the manual pump.
After this I added a high water alarm with a second high water pump. 2 electric 1 manual and the t as a last resort.
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Old 06-04-2013, 09:27   #13
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Re: What do you all think of engine-driven bilge pumps?

If you have room on the front of your engine to clutch a pump, they are superb. However most of us do not have that room.

The ones mounted on the prop shaft have three serious drawbacks. First, most of us have about 3:1 reductions so the RPMs are much lower and thus the capacity is greatly reduced. Second, you have to be motoring pretty fast in forward gear for them to work, which most of us will not want to be doing if you have a significant hole in the boat. And third, most of us don't have much room back there either.

If you have a decent battery bank and a large inverter, AC pumps can move a huge amount of water, and can be stowed anywhere and are "relatively" simple.

Portable gas or diesel run pumps (trash pumps) are required on most coded vessels, and can most a lot of water. But they need to be regularly used and maintained, which they often are not. And they are pretty big.

A combination of the above two . . . AC pump plus say a Honda 2000 gen is a workable hybrid solution. The Honda will get used in its normal gen/battery charging role, so will be used and maintained and actually run if needed in an emergency.

The normal dc electricity bilge pumps are ok for a trickle, but have no where near the flow rate to deal with a real hole in the boat. It's worthwhile for any skipper/owner to look at the inflow rate of a 1 1/2" hole in the boat 2' underwater and compare it to the typical electric bilge pump flow rate. It's eye opening. If you are depending on typical electric bilge pumps your priority MUST be to immediately find and plug (as well as possible) the hole. You need to get the inflow down to the "fast trickle" category ASAP. This is different from the above true "dewatering pumps" which can actually keep up with a relatively serious hole. . . . But of course you still want to plug it ASAP but they give you some time to do that and to deal with any other serious problems that may have occurred (like an injury).

Most cooling water">engine cooling water pumps do not move much water . . . Even less than the bigger dc bilge pumps. Personally I would prefer not to potentially compromise the engine (by possibly sucking trash into the cooling water system from the bilge) for the relatively small gain of its pumping capacity.
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Old 06-04-2013, 09:48   #14
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Re: What do you all think of engine-driven bilge pumps?

Engine driven bilge pumps are fine for emergencies. Electric driven should be your first line of defense against flooding. You already have an engine driven bilge pump with your raw water cooling pump. Putting a Y-valve on it and pointing a hose down into your bilge could save your boat if you ever have flooding and an electrical failure with your electric bilge pumps.
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Old 06-04-2013, 09:53   #15
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Quote:
Originally Posted by David M View Post
Engine driven bilge pumps are fine for emergencies. Electric driven should be your first line of defense against flooding. You already have an engine driven bilge pump with your raw water cooling pump. Putting a Y-valve on it and pointing a hose down into your bilge could save your boat if you ever have flooding and an electrical failure with your electric bilge pumps.
My understanding is that the raw water cooling pump moves very little water...what you see coming out your exhaust is the effective volume of water...nothing compared to even a small dc pump.
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