Massive bilge pump idea

[Tkeeth]

Why not just have several large bilge pumps? I bought a 12v 3500GPH pump on amazon for less than $100 and used it to empty my swimming pool in a few hours. A couple of those installed would do well. I am planning on adding at least 2 more bilge pumps to my 43 ft. Second stage is maybe large plastic sheets? should work, maybe depending on location and keel design.

https://www.amazon.com/Amarine-made-...rds=bilge+pump

[a64pilot]

I have two bilge pumps now, I think about 3500's as well. I'm counting on them too.
One is of course just a regular bilge pump, the other is mounted about a ft higher ( I have deep bilges) and it is also connected to a horn, its my high water alarm.
The trash pump would be a third bilge pump, for one thing I don't have any real confidence on a regular bilge pump running continuously, apparently it worked for you though if you emptied a swimming pool, and another is I don't want to have to plumb the things adding more thru hulls, the crash pump is something I can just store in a locker.

[Paul Elliott]

This is an interesting emergency bilge pump. It attaches to the prop shaft -- the engine needs to run.
Fast Flow Pumps - Bilge Pump

[a64pilot]

I might could fit that, what is the cost?

[Tkeeth]

Originally Posted by a64pilot

I have two bilge pumps now, I think about 3500's as well. I'm counting on them too.
One is of course just a regular bilge pump, the other is mounted about a ft higher ( I have deep bilges) and it is also connected to a horn, its my high water alarm.
The trash pump would be a third bilge pump, for one thing I don't have any real confidence on a regular bilge pump running continuously, apparently it worked for you though if you emptied a swimming pool, and another is I don't want to have to plumb the things adding more thru hulls, the crash pump is something I can just store in a locker.

My plan was to do it like I did my pool. I am rigging two up with roll up blue hose from the pool section at home depot, and rig the pump with alligator clips.

Hopefully, I cam keep the batteries up between the engine and generator to run these things for a while if needed. All wishful thinking I am sure, but who can afford to plan for every thing that "might happen", I just figure it gives me a little more time before either the helicopter comes or I get in the raft.

[sailingharry]

Originally Posted by Tkeeth

Why not just have several large bilge pumps? I bought a 12v 3500GPH pump on amazon for less than $100 and used it to empty my swimming pool in a few hours. A couple of those installed would do well. I am planning on adding at least 2 more bilge pumps to my 43 ft. Second stage is maybe large plastic sheets? should work, maybe depending on location and keel design.

https://www.amazon.com/Amarine-made-...rds=bilge+pump

The key word there is "several." The swimming pool pump I referenced does better than 5000 GPH at the installed conditions. Practical Sailor included 3 pumps rated at 4000 GPH, and they were all around 1500 GPH actual volume when installed. That means that to get the 5000 that a single pool pump would get, you'd need about 4 of those 3500 pumps. Of course, that makes sense -- those are 16 amp pumps, 4 of them is 64 amps, not much less than the 75 or so amps that I would expect the pool pump to draw.

Then comes installation. Are you going to gang all 4 into a single 2" header pipe with a single discharge (probably a good plan, if you add check valves) or have 4 individual runs and 4 thru hulls, which certainly adds redundancy.

Harry

[Tkeeth]

Originally Posted by sailingharry

The key word there is "several." The swimming pool pump I referenced does better than 5000 GPH at the installed conditions. Practical Sailor included 3 pumps rated at 4000 GPH, and they were all around 1500 GPH actual volume when installed. That means that to get the 5000 that a single pool pump would get, you'd need about 4 of those 3500 pumps. Of course, that makes sense -- those are 16 amp pumps, 4 of them is 64 amps, not much less than the 75 or so amps that I would expect the pool pump to draw.

Then comes installation. Are you going to gang all 4 into a single 2" header pipe with a single discharge (probably a good plan, if you add check valves) or have 4 individual runs and 4 thru hulls, which certainly adds redundancy.

Harry

I get that, but if you have plenty of room and money, install whatever you want. Several smaller 12V bilge pumps will be running long after your 110 trips out from being wet for alot less money and alot less room. Both are scarce on mine.

[puffcard]

After looking into this and being a former marine salvage person (as a teen). I bought the Rule Marine Evacuator High Capacity Dewatering 8000 GPM pump with a flat discharge hose rolled up with it. It's small, portable, lightweight, comes with 12 Vdc breaker & battery clips,. It's cheap and can move a ton of water in under two minutes. The 4000 GPM model is around $110 and comes complete, all you need to add is a flat discharge hose. You clip the battery leads on and hang the hose out the companonway. I worked with trash pumps, had 8 running on one salvage job, and they move water. However the Rule is simpler solution for sailboats.

https://www.amazon.com/Rule-Evacuato...6SGF8G14ZMNKGD

[Tkeeth]

Originally Posted by puffcard

After looking into this and being a former marine salvage person (as a teen). I bought the Rule Marine Evacuator High Capacity Dewatering 8000 GPM pump with a flat discharge hose rolled up with it. It's small, portable, lightweight, comes with 12 Vdc breaker & battery clips,. It's cheap and can move a ton of water in under two minutes. The 4000 GPM model is around $110 and comes complete, all you need to add is a flat discharge hose. You clip the battery leads on and hang the hose out the companonway. I worked with trash pumps, had 8 running on one salvage job, and they move water. However the Rule is simpler solution for sailboats.

https://www.amazon.com/Rule-Evacuato...6SGF8G14ZMNKGD

That's exactly what I was building!!

[puffcard]

Originally Posted by Tkeeth

That's exactly what I was building!!

The other cool thing is you can save another boater's bacon with this portable unit.

[Uncle Bob]

Originally Posted by Paul Elliott

This is an interesting emergency bilge pump. It attaches to the prop shaft -- the engine needs to run.
Fast Flow Pumps - Bilge Pump

Paul, nice idea however the shaft has to be turning to spin the impeller, and I am not sure that if you had a major leak you would want to be motoring hard while trying to find and fix the problem. It would however be good as a first line of defence if one was in a situation where one didn't know of a leak while motoring.

[puffcard]

Every time I gotten a leak while motoring, the motor was causing it. Twice had a broken exhaust line, once was a brand new boat just one hour after they finished the commissioning. But let's say you hit something, now you're trying to put a "crash pad" over a hole on the bow while the boat is going thru the water.

[Sailuke]

let me see. One man, scared for his life, and a five gallon bucket, calculate about 1 throw every 3 seconds, maybe the bucket's only filled up to about 4 gallons too, so 60 divided by three equals 20. 20 times 4 equals 80 gallons per minute. Three crew is 3 times 80 which equals 240 gallons per minute. Give the kids red solo cups, and the boat would be bailed even faster. Like the saying goes, "Nothing bails faster than a man and a bucket fighting the sea."

[Dockhead]

Originally Posted by Sailuke

let me see. One man, scared for his life, and a five gallon bucket, calculate about 1 throw every 3 seconds, maybe the bucket's only filled up to about 4 gallons too, so 60 divided by three equals 20. 20 times 4 equals 80 gallons per minute. Three crew is 3 times 80 which equals 240 gallons per minute. Give the kids red solo cups, and the boat would be bailed even faster. Like the saying goes, "Nothing bails faster than a man and a bucket fighting the sea."

4 gallons of water weighs 32 pounds. Really think you could lift that, and fling it overboard, 20 times a minute? Or even more, keep that up for an hour?

The thing about the scared man and the bucket is humor - not intended to be taken seriously.

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[Dockhead]

Originally Posted by SV DestinyAscen

The problem with relying on batteries is even if the Noah's crew were able to find the leak, slow it with rudimentary plugging, once the batteries got wet it is a matter of time Before it goes.

Say your two hour hypothetical, you had the boat relatively dry again with your contraptions and located the source of the leak, the battery will still probably die. IOW, mean time until failure becomes unacceptable once water hits the batteries.

To me good redundancy design considers the dominao of things that can go wrong and you start with the most reliable system to build your checklist from.

A battery system requires a functional diesel - a diesel powered system bypasses the electrical.

So why use the battery system? It'll be no more redundant than fitting a larger electrical proper bilge pump.

Choice of power source is a knotty problem. In my particular case, I chose a diesel generator mounted well above the waterline, with a switch to disconnect the boat electrical system from it (to prevent shorting out if parts of the wiring end up underwater). YMMV.

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