Massive bilge pump idea

[rh81]

Yeah, except it's the only gas engine I have, gas is old, the carb is gunked up and won't start...

Then you might be in serious trouble

But same could happen to any other sytem too....Battereies flooded, Inverter overheated, fuse blown.....

Best would be to have some different sytems together: AC trash pump, Honda, Bilge pumps

[sailingharry]

Originally Posted by rh81

How about an small motor pump from Honda. It pumps around 158 Gallons per Minute and is portable, independent from batteries or the main engine. Costs around 500.- Euro

https://motorgarten.de/honda-wasserp...5cLhoCB_7w_wcB

That's pretty awesome, indeed. It's also about $500 US for the bigger one, so cost is pretty reasonable. However, it's worth noting that they are 35-60 gallons per minute, not 158 gallons per minute. Still 60 GPM is still bigger than the biggest Jabsco engine mounted pump, at 1/4 the cost.

Fuel and storage, as others have noted, is a challenge, although it could fit in whatever system you have for outboard fuel.

Harry

[S/V Illusion]

Originally Posted by sailingharry

Pool pumps through 1.5hp are designed with 1.5" piping, which is only 1/4" larger than most large bilge pumps. As far as the thruhull, this would work very nicely installed very high on the transom (within and inch or two of the rail) since water dribble and other cosmetic concerns are not going to be a concern on a never-used system. And the head loss calculations I did were based on 1.5" piping, not 6" piping.

Harry

My comments were predicated on the hydrodynamic considerations of large flow rate through different diameter pipes/hoses. In every scenario proposed, the limiting factor is the limitation created by non-laminar flow through hoses typically used on boat, not head loss or pump capacity rating. While these latter two considerations clearly effect flow, the larg(er) size pumps people describe are rendered effectively useless by virtue of the hose diameter of 3inches or less.

Adding a bigger pump without considering the system as a whole is essentially a 'feel good' exercise.

[Cheechako]

I'm more in the camp of buying a boat designed and also built to survive than trying to fix the "ultimate leak" after the fact. (Thick hull, long keel, non spade rudder, tapered bronze seacocks , everything in known new or near new condition.)
But if you want to remove a lot of water get a Honda Gas trash pump. Pre-think and pre-rig it for your ultimate emergency.

[Mango51]

Originally Posted by sailingharry

I am equally curious about not being able to find the source. However, they were in communication with event organizers who provided some input and suggestions, and I would assume that "close thru-hulls" was mentioned at some point. Also, most organized offshore events have considerable prep requirements, and I suspect that would rule out complete greenhorns. I have to assume it wasn't easy.

As far as bulkheading, I'm not sure it would be all that easy. I have thru-hulls in my engine compartment, lazarette, forepeak, head, and galley. I can't imaging ANY way of making those compartments watertight -- and if I did, that would naturally mean individual bilge pump systems for each one (can't drain to the main bilge) for a total of 5 bilge pump systems on a 34 foot boat! It can be done, for sure, although as you mentioned few people would appreciate the layout and fewer would appreciate the cost. If that is the accepted standard for offshore capable boats, there would be few that would be able! Certainly no coastal cruisers that could be upgraded for that use.

Harry

Drainage is accomplished through plumining. With seacocks at every bulkhead. Every compartment drains to bilge intrupted by the seacocks. You close the dog door and seacock and fix the problem later on.

[fatherchronica]

I have considered the gasoline trash pump over the years, a good pool pump is a cool idea. As far as needing to reprime like in a pool, unless you are in a really big vessel with a deep bilge and 8 foot of freeboard I doubt that would be an issue. And saltwater would not be an issue, because it would not be exposed until you fired it up. With that kind of volume, if you aimed it out of the stern it would propel you to your destination until you ran out of fuel. Hopefully you would have found a way to stem the flow by then, and if the pump rusted up you wouldn't need it this voyage again.

[Exile]

Originally Posted by S/V Illusion

My comments were predicated on the hydrodynamic considerations of large flow rate through different diameter pipes/hoses. In every scenario proposed, the limiting factor is the limitation created by non-laminar flow through hoses typically used on boat, not head loss or pump capacity rating. While these latter two considerations clearly effect flow, the larg(er) size pumps people describe are rendered effectively useless by virtue of the hose diameter of 3inches or less.

Adding a bigger pump without considering the system as a whole is essentially a 'feel good' exercise.

https://en.wikipedia.org/wiki/Laminar_flow

Interesting consideration, except over my head. Any chance of someone explaining this limitation as applied to some of the pump scenarios that are being considered? Would hate to take any additional time & money trying to make myself feel more secure when it is in reality an exercise in futility.

[Steadman Uhlich]

I don't wish to derail this topic, but given that everyone here is interested in pumps for use in an emergency, I would like to pose a question that I think is related. I hope you will answer based on the scenario outlined below. I have selected a single pump (from one mentioned earlier) and a single battery, to keep this scenario simple.

Assume your 35 foot boat is taking on water through a 2 inch hole, 3 feet below waterline. That hole puts 4,152 Gallons Per Hour (GPH) into the boat.

Assume your engine will not start, after several failed attempts. It is not usable in this emergency. You have no generator, no gas powered pumps, and you have no time to charge any batteries by using solar panels (which you don't have).

Remember this scenario condition: You only have ONE 12V battery available now to run your electric bilge pump.

You have only a single dedicated 12v Starting Battery (an ordinary wet cell that is a few years old, but still holds enough charge to start the engine when needed) that you have just been using to try to start the Diesel engine. You tried to start your engine about 8 times with no success. You are now concerned about discharging it further as you need it for your electric bilge pump. Your other "house" battery is not available or charged, due to previous discharge during the stormy night and then some short due to rising water in the bilge that rose over the batteries which were stored low in the boat.

You want to use a high volume bilge pump to dewater the boat ASAP, or as much as possible given these limits. The pump is a Rule Evacuator 4000GPH model pump. It is attached by alligator clips to the Start Battery, when needed, which is NOW. So, while your feet are wet as water sloshes over the cabin sole, you connect the alligator clips for the emergency bilge pump to the partially discharged engine start battery, and start pumping.

The pump has the following specs:
Rule Evacuator Pump 4000GPH uses 20 Amps, 1.6 HP, 12 volts.

How many Watts does that take? You found a formula and calculated:
I (Electrical) HP = 746 Watts. Therefore P(Watts)= 746 X 1.6 HP = 1193.6 Watts.

Big Question: How long do you think that pump will run (at rated speed, not a trickle) if you have only that one (start) battery available to use?. Please post your guess below.

[sheldon957]

Your engine is the best water pump you have. As long as it can run you will pump out huge amounts of water. Plumb it with an inlet water line that you can open up.

[Bleemus]

Originally Posted by sheldon957

Your engine is the best water pump you have. As long as it can run you will pump out huge amounts of water. Plumb it with an inlet water line that you can open up.

I am sorry but this is just really bad advice. Put a five gallon bucket under your engine exhaust and time how long it takes to get five gallons.

[a64pilot]

Steady, that is a ridiculous scenario

[Steadman Uhlich]

Originally Posted by a64pilot

Steady, that is a ridiculous scenario

Obviously I don't see it that way.

But, why do you think so?

The scenario is written as it is to restrict the pump's use to a single battery that may be usable and movable to a higher position if needed during water rising over the sole.

And while some boats may have large battery banks, I think it is best to consider what one would do in a case where you have the minimum available to you (i.e. A single battery), and, in this case a single electric pump.

[ur2slo]

Best way to prepare for ALL unforeseen situations?................DONT GO SAILING.

Jeez .................

[SV DestinyAscen]

I'd guess ten minutes.

Wouldnt waste time with it really - if the diesel isn't working, if I can't find the source of the leak, ingres of water at the rate yiure specifying - I'd be abandoning boat and trying to making communication and running through checklist.

[puffcard]

On dad's old boat a T-42, we tee off the SW engine Inlet, just above the thru-hull. Added a ball valve and a couple feet of hose to a strainer in the bilge. Cost about $60 and provided a simple backup/added bilge pump. He thought it was pure cleverness, of course he didn't think of it. All he had to do was shut the hull valve and open the globe valve to the strainer. When dewatering it's all pumps on hand to work.