Massive bilge pump idea

[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

[Pete7]

Certainly the lightweight Honda pumps look interesting for a small yacht which won't have a genny, or a large battery bank to power a decent sized inverter. The cost of the inverter is going to be the same as a 4 stroke petrol pump.

Overview – Lightweight – Water pumps – Industrial – Honda

[rh81]

The big advantage is that Honda works also when the engine room is flooded or the batteries are gone

[sailingharry]

Originally Posted by Dockhead

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.

Dockhead, your choice of power is a key part of what got me thinking about this idea. I didn't include it in the initial discussion because it works equally well for many cruisers without a generator -- most cruisers, even budget level, have a decent alternator (100A or so) and an inverter (everyone wants to run a laptop, and a lot of cruisers run a microwave, etc..). But, as I get closer and closer to selling my work-life coastal weekend cruiser and move toward an offshore capable life-aboard retirement boat, a generator is high on my expected amenities. That makes this solution even more redundant -- generator first (lower fuel consumption, and probably mounted higher in the boat -- maybe even above the batteries), backed up by inverter on batteries with or without alternator (a 400 Ah bank will run this for 2-3 hours).

Harry

[Dockhead]

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

This has some advantages, but also some really big disadvantages:


1. You can't store either the pump or the fuel inside the hull volume, because of the problem of petrol/gasoline vapors. Where will you keep it? Won't it rust out if you keep it in the anchor locker?

2. If you don't use it regularly, the carburetor will gum up and you won't be able to start it.


I thought about this, but judged it to complicated to store and too risky concerning starting.

A diesel powered one would avoid BOTH problems, but I couldn't find a reasonably compact and light one.

[Exile]

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

Just a typo I'm sure, but worth noting that these Rule submersible pumps are rated at gallons per hour (GPH) vs. minute. After weighing pros & cons, I also went this route for an emerg. bilge pump, but with the Rule 4000 that has the 2" discharge outlet. I hard-wired it (with a fuse) to my 8D dedicated engine start battery and then attached a USS float switch so all I have to do is drop it in a flooded bilge for it to activate. I keep it lashed high & dry in the engine compartment.

Be careful relying on collapsible hose. I tested the set-up described above on my hot tub at home with about a 6' rise (similar to the boat) and it would not create sufficient pressure to open up the (2" diam.) collapsed hose. YMMV, and I would imagine the Rule 8000 might do the trick, but worth testing first. I wound up using inexpensive plastic bilge hose -- rolls up fairly compactly but still takes up a lot more space than the collapsible. My idea would be to run the hose out the nearest porthole and over the side in an emergency.

There are few good answers for this dilemma but Dockhead's old thread does a great job of analyzing all the various pros & cons. Even a succession of high capacity 12v options are unlikely to be enough in a serious flooding incident. The AC-powered trash pump seems like a good option for those with generators or perhaps sufficient inverter/battery capacity, but rely on critical boat systems to continue running. The gasoline-powered trash pump may be even better since it operates independently of boat systems, but then there are the problems of stowage for a gas-operated device, and whether a gas engine will actually run when needed. The ethanol-free, canned gas that A64 mentioned is a must for storage. The shaft-driven pump that Paul linked to seems somewhat promising but has drawbacks as mentioned.

[Exile]

Originally Posted by Dockhead

This has some advantages, but also some really big disadvantages:


1. You can't store either the pump or the fuel inside the hull volume, because of the problem of petrol/gasoline vapors. Where will you keep it? Won't it rust out if you keep it in the anchor locker?

2. If you don't use it regularly, the carburetor will gum up and you won't be able to start it.


I thought about this, but judged it to complicated to store and too risky concerning starting.

A diesel powered one would avoid BOTH problems, but I couldn't find a reasonably compact and light one.

I had this exact problem storing the otherwise venerable Honda 2000 in my fwd lazarette (after running it out of fuel). It corroded badly in a fairly short period of time, and always had trouble starting. I guess you could spray it down with WD-40 and store it on deck (or maybe in the cockpit), but it's problematic as you say.

[Matt Johnson]

I'd rather have a Honda 2000 and one of those 110v pumps. At least the gen would get used enough to know it works..... plus you can use it for many other chores.

Matt

[a64pilot]

I think if you run the Honda dry and store it, months or even years later if will work fine.
I motorized this bicycle with a little Honda maybe ten years ago as it folds up and I can put it in an airplane and have a way to get around little country airports and towns. I run if off 100LL mostly as that is what is in the airplane, just drain a little out for the bike. 100LL will store almost forever and not go bad.
It sits for months, maybe a year or so, but always starts up in a couple of pulls and runs fine, never cleaned the carburetor and never run it dry or anything. If you had that expensive fuel that is sold at Home Depot etc. I think it would work fine

[puffcard]

Originally Posted by Exile

Just a typo I'm sure, but worth noting that these Rule submersible pumps are rated at gallons per hour (GPH) vs. minute. After weighing pros & cons, I also went this route for an emerg. bilge pump, but with the Rule 4000 that has the 2" discharge outlet. I hard-wired it (with a fuse) to my 8D dedicated engine start battery and then attached a USS float switch so all I have to do is drop it in a flooded bilge for it to activate. I keep it lashed high & dry in the engine compartment.

Be careful relying on collapsible hose. I tested the set-up described above on my hot tub at home with about a 6' rise (similar to the boat) and it would not create sufficient pressure to open up the (2" diam.) collapsed hose. YMMV, and I would imagine the Rule 8000 might do the trick, but worth testing first. I wound up using inexpensive plastic bilge hose -- rolls up fairly compactly but still takes up a lot more space than the collapsible. My idea would be to run the hose out the nearest porthole and over the side in an emergency.

There are few good answers for this dilemma but Dockhead's old thread does a great job of analyzing all the various pros & cons. Even a succession of high capacity 12v options are unlikely to be enough in a serious flooding incident. The AC-powered trash pump seems like a good option for those with generators or perhaps sufficient inverter/battery capacity, but rely on critical boat systems to continue running. The gasoline-powered trash pump may be even better since it operates independently of boat systems, but then there are the problems of stowage for a gas-operated device, and whether a gas engine will actually run when needed. The ethanol-free, canned gas that A64 mentioned is a must for storage. The shaft-driven pump that Paul linked to seems somewhat promising but has drawbacks as mentioned.

Thanks was a typo. Good point about back pressure of flat discharge hoses, and should test all.

[a64pilot]

A flat hose should have no back pressure, just the weight of the water as how much pressure does it take to inflate a light weight hose, 1 PSI?

[Exile]

Originally Posted by a64pilot

A flat hose should have no back pressure, just the weight of the water as how much pressure does it take to inflate a light weight hose, 1 PSI?

Not sure. Maybe the type of material had something to do with it. It was some sort of reinforced plastic stuff. Maybe more typical fire hose made from a canvas-type material would be easier to overcome.

[Dockhead]

Originally Posted by sailingharry

Dockhead, your choice of power is a key part of what got me thinking about this idea. I didn't include it in the initial discussion because it works equally well for many cruisers without a generator -- most cruisers, even budget level, have a decent alternator (100A or so) and an inverter (everyone wants to run a laptop, and a lot of cruisers run a microwave, etc..). But, as I get closer and closer to selling my work-life coastal weekend cruiser and move toward an offshore capable life-aboard retirement boat, a generator is high on my expected amenities. That makes this solution even more redundant -- generator first (lower fuel consumption, and probably mounted higher in the boat -- maybe even above the batteries), backed up by inverter on batteries with or without alternator (a 400 Ah bank will run this for 2-3 hours).

Harry

Indeed. I also liked the fact that there are several different ways to power an AC trash pump.

My choice of power was greatly helped by the fact that my generator is mounted quite high and that I was able to isolate it from the rest of the electrical system. If it were mounted below the waterline, or if I had only alternator and inverter, I would think twice about it -- I really wanted the system to work even with the engine drowned.

My generator is a heavy duty one and very reliable. And I have an inverter capable of running the 2.2kW trash pump motor (including startup loads) via either batteries or large frame school bus alternator. This is a fair amount of redundancy which I like.


I think the best solution of all probably is a portable diesel powered pump, but it's heavy and bulky. Probably only realistic on quite large vessels.



Someone above mentioned AC trash pump plus Honda 2000. I think that's an excellent solution if the Honda 2000 is in regular use for other purposes. This has a great advantage that it is automatically isolated from anything which could short it out, and you run it on deck where it won't get drowned by flooding.

[rh81]

@Dockhead
Good point but with the outboard engine you also have to deal with gas.

If you run it dry and spray it with WD40 you should be able to store it inside. Take it out twice a year, top up some gas and start it, let it run dry and store it again.

The AC pump is also a good idea but you have to be careful with the powercord in such a situation

[Tkeeth]

Originally Posted by rh81

The big advantage is that Honda works also when the engine room is flooded or the batteries are gone

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