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Old 03-07-2015, 08:01   #1
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Submersible Trash Pump for Emergency Use

I am preparing for an extended coastal cruise and have been looking to add additional dewatering capacity. The standard recommendation is to add a 2nd 12vdc bilge pump but none that I've found would really have capacity to "save the boat" if necessary and I don't have room to install an engine-driven pump.
So I am considering a small commercial-grade submersible trash pump that will pass a 2" obstruction and pump 110 GPM - but it runs on 110vac. We carry a Honda generator on board so providing electricity would not be problem.
Apart from the obvious disadvantages of high voltage and hoping the generator will start when I need it... has anyone in this forum used a similar setup? Or, can you recommend an alternative?

Thanks in advance.
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Old 03-07-2015, 08:11   #2
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Re: Submersible Trash Pump for Emergency Use

No pump will "save the boat" if a 2" hole is opened in the hull. Boats take a long time to sink though. Best use of time is spent finding the hole and stemming the flow. After that dewatering pump size is just a matter of how much time it takes to get the water out. If you can't stem the flow get out the life raft and EPIRB.
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Old 03-07-2015, 20:14   #3
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Re: Submersible Trash Pump for Emergency Use

Quote:
Originally Posted by transmitterdan View Post
No pump will "save the boat" if a 2" hole is opened in the hull. Boats take a long time to sink though. Best use of time is spent finding the hole and stemming the flow. After that dewatering pump size is just a matter of how much time it takes to get the water out. If you can't stem the flow get out the life raft and EPIRB.

A 2" hole at 3ft below the water line is going to flow at around 100gpm. There are a number of small gas powered trash pumps that would be practical in this situation. Even the 12v Rule 8000 would probably keep up. But to your point, 100gpm will require something fairly specialized and not easily installed.


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Old 04-07-2015, 00:35   #4
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Re: Submersible Trash Pump for Emergency Use

The OP said "PASS A 2" OBSTRUCTION" i.e., a 2" piece of trash. Nothing about the size of the hole in the boat.
Sheesh.
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Old 04-07-2015, 02:38   #5
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Re: Submersible Trash Pump for Emergency Use

If you have a big hole in the boat is your time better spent finding and plugging the hole or getting out a generator, starting it, finding the pump stashed somewhere in the bottom of a locker, running a large hose out the cabin, and plugging in the pump?

I think if you have a big pump, it needs to installed to pump when you flip a switch. Then you have time to do something about the hole.
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Old 04-07-2015, 02:50   #6
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Re: Submersible Trash Pump for Emergency Use

Asking a pump to pass a 2" piece of trash through it is kind of unrealistic in my experience. And most pumps, regardless of how they're driven, have a strainer on the intake hose.
The only thing which might have a shot at meeting those requirements, is a Super Heavy Duty, Commercial macerator pump. And I say "might", as just imagine what kind of pump it'd take to be able to digest say, 20' of 3/4" dock line, or a T-shirt or kitchen towel.
Not many motors have that kind of torque, let alone blade, & impeller setup. Such is a specialized beast indeed.

That said, you might look into pumps powered by their own built in gasoline engines, thus skipping some of the fragile electrical connections which you mentioned. Not that there aren't fragile electrical circuts in a lot of gasoline engines. But if you find something that's 2-cycle, & starts with a pull cord, some of those weaknesses are eliminated.
I can't say that I'd particularly trust a pump which depended on a household electrical cord, to keep me afloat in an emergency. Too many ways for Mr. Murphy to intervene.

On the Diesel options side of the house, you can rig up your main engine's intake to be used with/as part of an Eductor. And thus, it functions as a dewatering pump, without a lot of the drawbacks of the "standard" damage control mode. Where people use their engine's raw water intake as the suction side of a pump.

When you look them up, they may seem a bit odd, but we had/used them when I was Navy, & they work quite well. Plus, they're less subject to clogging than a standard pump. Albeit, a good strainer on them, is still a wise idea.

Yes, you'd need a few hoses, plus a Y-valve on the engine's intake. But with the proper type of quick connect hose fittings, you can assemble one in seconds/under a minute.

Also, there are other, commercial/professional grades & types of pumps that are a lot more heavy duty than anything you'll find in a catalog full of "yachting" gear. So it's worth doing some digging there for other alternative solutions.
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Old 04-07-2015, 03:11   #7
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Re: Submersible Trash Pump for Emergency Use

I'm not really familiar with eductors (other than in a lab as a way to make a vacuum), but one chart I found had at best you have a little better than a 1:1 suction to motive flow rate. So for my 8 GPM 3GM30 at high rpms is about 8 GPM of dewatering. 10% of the flow rate of what the OP was talking about.

Quote:
Originally Posted by UNCIVILIZED View Post
Asking a pump to pass a 2" piece of trash through it is kind of unrealistic in my experience. And most pumps, regardless of how they're driven, have a strainer on the intake hose.
The only thing which might have a shot at meeting those requirements, is a Super Heavy Duty, Commercial macerator pump. And I say "might", as just imagine what kind of pump it'd take to be able to digest say, 20' of 3/4" dock line, or a T-shirt or kitchen towel.
Not many motors have that kind of torque, let alone blade, & impeller setup. Such is a specialized beast indeed.

That said, you might look into pumps powered by their own built in gasoline engines, thus skipping some of the fragile electrical connections which you mentioned. Not that there aren't fragile electrical circuts in a lot of gasoline engines. But if you find something that's 2-cycle, & starts with a pull cord, some of those weaknesses are eliminated.
I can't say that I'd particularly trust a pump which depended on a household electrical cord, to keep me afloat in an emergency. Too many ways for Mr. Murphy to intervene.

On the Diesel options side of the house, you can rig up your main engine's intake to be used with/as part of an Eductor. And thus, it functions as a dewatering pump, without a lot of the drawbacks of the "standard" damage control mode. Where people use their engine's raw water intake as the suction side of a pump.

When you look them up, they may seem a bit odd, but we had/used them when I was Navy, & they work quite well. Plus, they're less subject to clogging than a standard pump. Albeit, a good strainer on them, is still a wise idea.

Yes, you'd need a few hoses, plus a Y-valve on the engine's intake. But with the proper type of quick connect hose fittings, you can assemble one in seconds/under a minute.

Also, there are other, commercial/professional grades & types of pumps that are a lot more heavy duty than anything you'll find in a catalog full of "yachting" gear. So it's worth doing some digging there for other alternative solutions.
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Old 04-07-2015, 09:55   #8
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Re: Submersible Trash Pump for Emergency Use

I agree with find where the water is coming in and stop or slow down the flow first , what is the size of the pump you have now,
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Old 04-07-2015, 10:01   #9
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Re: Submersible Trash Pump for Emergency Use

Have engine driven pump designed for your needs. Remember the boats Diesel engine will run until the water gets above the air intake as the diesel does not need a spark i.e electricity to run. Erickson Safety Pump in various sizes. From the Land of OZ. Google for pics and data. Not cheap but slick, mine was $1,000 in 2000. Russ
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Old 04-07-2015, 10:18   #10
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Re: Submersible Trash Pump for Emergency Use

Quote:
Originally Posted by BigIdea View Post
I am preparing for an extended coastal cruise and have been looking to add additional dewatering capacity. The standard recommendation is to add a 2nd 12vdc bilge pump but none that I've found would really have capacity to "save the boat" if necessary and I don't have room to install an engine-driven pump.
So I am considering a small commercial-grade submersible trash pump that will pass a 2" obstruction and pump 110 GPM - but it runs on 110vac. We carry a Honda generator on board so providing electricity would not be problem.
Apart from the obvious disadvantages of high voltage and hoping the generator will start when I need it... has anyone in this forum used a similar setup? Or, can you recommend an alternative?

Thanks in advance.
Hi Big Idea,

A crash pump projects is in the works here as well.

In addition to this forum, another source we find very useful is Attainable Adventure Cruising. We can heartily recommend consulting their excellent [commercial] site (which also has an article [with many qualified comments] on this topic from August 2014 that will answer your questions in a very qualified way.)

That is the direction we are going with our crash pump project as well.

We hope you have fun with your project.

Cheers!
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Old 04-07-2015, 10:32   #11
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Re: Submersible Trash Pump for Emergency Use

Maybe we can better answer your question if we know why you think this big pump is necessary. Also, check the power requirements of a 100GPM pump against your generator output. I doubt an 1,800W Honda portable generator can run a 100GPM pump if it is really moving 100GPM up any significant height.

If you research this subject a bit you find that a trash pump (AC or engine driven) does not prevent sinking very often. In fact, many boats are abandoned and the boat survives. It would take a very specific type of damage to make a trash pump useful. Only a very narrow range of hull penetrations (from about 0.5" to 1") will allow a really big pump to save the boat. A small leak like that should be easily handled by the crew with a modest damage control kit readily avaiable. The leaks that a trash pump will help can usually be found and the flow stemmed in less time than it takes to get the pump up and running. A really big leak say 2"+ will overcome any size pump you can carry on a small cruising boat.

Any time there is a leak no matter how big the key is finding it and reducing the flow as quickly as possible. Pumps generally come into play once the flow is stemmed. If after doing all that is possible to stem the flow and you still have 3,000+ gallons per hour coming in it may be better use of time and energy to focus on saving the crew because the flow rate will steadily increase with time.
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Old 04-07-2015, 11:32   #12
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Re: Submersible Trash Pump for Emergency Use

Many decades ago, when I was in the USCG, we would drop a trash pump to a boat in trouble.
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Old 04-07-2015, 12:32   #13
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Re: Submersible Trash Pump for Emergency Use

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Many decades ago, when I was in the USCG, we would drop a trash pump to a boat in trouble.
That happens sometimes even today but those pumps are big and pump more than 100GPM. These pumps are normally run by direct drive diesel or gasoline engines. There is almost no practical way a small cruising yacht could carry one around.
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Old 04-07-2015, 12:36   #14
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Re: Submersible Trash Pump for Emergency Use

Quote:
Originally Posted by BigIdea View Post
I am preparing for an extended coastal cruise and have been looking to add additional dewatering capacity. The standard recommendation is to add a 2nd 12vdc bilge pump but none that I've found would really have capacity to "save the boat" if necessary and I don't have room to install an engine-driven pump.
So I am considering a small commercial-grade submersible trash pump that will pass a 2" obstruction and pump 110 GPM - but it runs on 110vac. We carry a Honda generator on board so providing electricity would not be problem.
Apart from the obvious disadvantages of high voltage and hoping the generator will start when I need it... has anyone in this forum used a similar setup? Or, can you recommend an alternative?

Thanks in advance.
We have a submerisable AC pump that was designed for a basement sump pump as our crash pump -- from Home Depot. Decent price for a high output pump. We have a fixed genset, so getting AC to it is pretty straight forward. If your Honda is not fixed mounted, then you may have a hard time using it in the conditions it may be required.
The purpose of the pump is to give you more time and ability (lower-water level) to find the leak and slow the leak.
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Old 04-07-2015, 12:41   #15
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Re: Submersible Trash Pump for Emergency Use

Where do "holes" usually happen in a fiberglass sailboat?

Options to consider:

- Where is the water (out-to-sea, in the Bays, at the dock, etc.)

- What part of the boat (ie Where to look for the hole - if not obvious!)

What obstacle (away from the dock) is usually the culprit for puncture of the skin?

Here's hoping it never happens to you,

Dennis

Jubilee-40' x 16' gaff-rigged ketch (ferro-lite over wood planking)

Collusion-proofed!
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