Submersible Trash Pump for Emergency Use

[transmitterdan]

Originally Posted by cajucito

1.An underwater camera with led lights on a telescopic pole linked to a portable DVD player. It will be quicker to find the hole by surveying the outside of the hull underwater than ripping up large amounts of the furniture and fittings inside to locate the ingress

I would test this to see how it works before trying it in anger. When the seas are really up trying to hang over the side with a selfie stick in the water can be pretty dangerous. Not all water is clear like the Caribe so LED lights underwater often show just a lot of back scatter.

Consider whether it will be feasible to see the video in real time. A hole in the hull doesn't have to be big to cause a lot of incoming water. Randomly taking video then downloading it to see what's going on plus trying to figure out exactly where the camera was at all times is not that simple. And it can take a lot of precious time to go over the entire hull(s).

One of those little cameras on a flexible stalk can be pretty handy when trying to find a leak from the inside. They can reach up into places a person could never get with their eyes. But once the leak is found the busted up furniture to get at it is probably among the least of concerns.

[RaymondR]

Interesting problem I have pondered on many times:

Belt drive a high volume centrifugal from the front of the main engine. With the small amount of lift required you could probably drive a 4" x 3" and move lots of water?

Cowl to fit behind prop on outboard. Don't know what you could lift but some large volume low head irrigation pumps use a propeller in a conduit?

I have an AC driven 1 1/4 outlet pump and 2.2kW gen set and a T and valve into the main bilge pump discharge. Have used it to keep up when doing in-water stern gland changes and always rig it when I leave the boat in a marina and have shore power. It has it's own float switch.

Never gotten quiet paranoid enough to really explore and have a steel boat anyway.

[Dockhead]

In my opinion, the OP is on exactly the right track. This pump:

HondaWSP100 Model Info | Submersible Water Pump | Honda Pumps

For example, moves 150 gallons a minute (nominally) of debris-filled water on a 1 hp motor needing 47 amps of startup current @ 110 volts, and 11 amps to run, demand well within the capacity of average sized generators and inverters.

No installation is required; just store it with a roll-up fire department type hose and Bob's your uncle.

I think this is an absolutely superior solution to the nightmare of needing to dewater the boat after a major leak. Don't forget that in major flooding incidents bilges typically fill up with debris, which often clogs normal bilge pumps, adding yet another problem to an already crisis situation. A big trash pump is just the dog's danglies for such a cash.

As others have said, you dramatically improve your chances of finding and fixing a leak if you can keep the water under control for a while. This is the way to do it. I suppose not that many boats sink at sea because of leaks, but it happens every year, a $1000 or so worth of gear with no installation required seems like cheap insurance to me.

Why electric?

The downside of electric is you need for your boats electrical systems to be working. If you don't have a generator, then this is worse, since flooding can kill your battery banks.

If you do have a generator, however, then how much more likely is the generator to be working, than a gasoline engine which is run infrequently? Are you ready to run your emergency dewatering pump every couple of months, keep the carb clean, etc.? A device you will likely never use and will just be in storage for years and years? Even a diesel dewatering device will need regular operation to maintain reliability. I would much rather rely on my generator, which I use constantly and keep in top condition, as the power source. Backed up by inverter and batts or inverter and main engine alternator -- fully three power sources for the pump, which can be stored without maintenance for years. This is the best way to do it.

[Dockhead]

Originally Posted by transmitterdan

I would test this to see how it works before trying it in anger. When the seas are really up trying to hang over the side with a selfie stick in the water can be pretty dangerous. Not all water is clear like the Caribe so LED lights underwater often show just a lot of back scatter.

Consider whether it will be feasible to see the video in real time. A hole in the hull doesn't have to be big to cause a lot of incoming water. Randomly taking video then downloading it to see what's going on plus trying to figure out exactly where the camera was at all times is not that simple. And it can take a lot of precious time to go over the entire hull(s).

One of those little cameras on a flexible stalk can be pretty handy when trying to find a leak from the inside. They can reach up into places a person could never get with their eyes. But once the leak is found the busted up furniture to get at it is probably among the least of concerns.

+1. I can't see that working except with a very small leak in very calm weather.

As to finding the leak from the inside -- woe is you if you have a full hull liner.

[transmitterdan]

Originally Posted by Dockhead

In my opinion, the OP is on exactly the right track. This pump:

HondaWSP100 Model Info | Submersible Water Pump | Honda Pumps

For example, moves 150 gallons a minute (nominally) of debris-filled water on a 1 hp motor needing 47 amps of startup current @ 110 volts, and 11 amps to run, demand well within the capacity of average sized generators and inverters.

Such a pump might not be able to be started/run by a portable Honda generator as the OP suggested was the idea. Marginal power or not an emergency pump system should be tested periodically to be sure. Powering from an inverter will draw about 125A from a 12V bank assuming it can provide the starting current. How long the bank will last with that kind of draw is a concern. If you have the storage space and a big enough permanently installed generator then this kind of pump can work. But I still think on balance the precious minutes spent getting it all set up and running would be better spent finding and plugging the leak. It's easy to underestimate how much time could be lost. The bigger the leak the faster it must be found.

I am not against pumps. Big bilge pumps permanently installed with an automatic switch can buy some time. But the thing that buys the most time is a reliable alarm. The earlier the leak is found the better in almost every scenario.

[Dockhead]

Originally Posted by transmitterdan

Such a pump might not be able to be started/run by a portable Honda generator as the OP suggested was the idea. Marginal power or not an emergency pump system should be tested periodically to be sure. Powering from an inverter will draw about 125A from a 12V bank assuming it can provide the starting current. How long the bank will last with that kind of draw is a concern. If you have the storage space and a big enough permanently installed generator then this kind of pump can work. But I still think on balance the precious minutes spent getting it all set up and running would be better spent finding and plugging the leak. It's easy to underestimate how much time could be lost. The bigger the leak the faster it must be found.

I am not against pumps. Big bilge pumps permanently installed with an automatic switch can buy some time. But the thing that buys the most time is a reliable alarm. The earlier the leak is found the better in almost every scenario.

Obviously, the power source has to be capable of starting and operating the pump, or it makes no sense whatsoever.

My generator, inverter, and battery bank are all easily capable of that. My generator can provide continuous power at more than the startup draw of that pump. My inverter can supply that much power for 30 seconds. A portable Honda generator might or might not do it.