Emergency bilge pump

Menzies thread on his emergency bilge pump reminded me of something I have been thinking about occasionally. So I thought a poll on emergency bilge pumps could be interesting.

A couple of months ago I had a survey for insurance. The surveyor was asking about bilge pumps of course, but then probed a bit about 'emergency bilge pumping'. He was hinting that I ought to have a gas trash pump on board, say 3" size. He did not put it in the report though.

I have given some thought to doing something, but so far nothing I like has emerged. There are the devices that can fit on your prop shaft, but then you need to be moving, and at a reasonable speed to turn the pump fast enough. I really would prefer to not have another gas engine on board. I have a pair of Honda 2000 gennies, and a scuba compressor on the boat deck. None get much use. To have yet another one sitting mostly unused seems un-necessary clutter (until its needed!).

A hydraulic pump could be the answer. I would like a stern thruster and my 8HP electric bow thruster is marginal in tern of capacity. My Naiad hydraulic pump on the Starboard engine probably isn't up to the tasks of thrusters and trash pump. But I guess I could install a suitable pump on the Port engine. I can see the exercise adding up to a lot of boat bucks quite quickly, so not high on my 'to do' list at this point.

There are a variety of clutch driven pumps you can run off your engine by belts.

http://online.anyflip.com/ucrc/jfuq/mobile/index.html#p=38

My boat has 2 bilges that connect after 18" of water in the bilge. There are 4 pumps rated at near 10K gallons per hour. My bilges are dry. If I need more than that, there will be a small difference between needing a 3" or 6" pump. I would like to see some numbers for how many boats were saved or lost because they did or didn't have a 3" pump. If you're crossing oceans it may be a different story, but for most of us the possibility of lifesaving need seems incredibly small.

Ted

I have an Edison portable manual pump.

If the hole is too big for me to plug, pumps are not going to help.

I have a 60GPM at a 10’ head stainless steel industrial dewatering pump.

It runs on 120 volts and draws a bit over 10 amps. It has a 2” discharge 25’ of hose and cam lock fittings.

This pump and hose sits ready in a cabinet in my salon. I can bring it into service in less than 60 seconds.

I chose not to permenantly install it because I want the flexibility to use it where it is needed quickly. For exampe if I have a collission I can deploy it forward. If it is needed in the engine compartment I can deploy it there. If a fellow boater has a emergency it can be used to help them.

tiltrider1 said:

If the hole is too big for me to plug, pumps are not going to help.

Click to expand...

One of my favorite subjects, said the man who’s boat sank.
The pumps are there to buy you more time to plug the leak or for help to arrive.
The more pumping capacity, the more time before you have to swim.

I was once on about a forty foot sport fish. We had been backing on a large fish for a long time and a lot of water had come aboard and gotten below deck. We eventually noticed water was coming in the freeing ports, not going out. There was only two Rule 1500 bilge pumps aboard. It was touch and go for a while and I considered cutting the engine intake hose at the seacocks which were about a foot underwater. The Coasties arrived with a 3” gas pump that turned the tide. (Turned the tide, I like that!)

On my own boat I had installed a Rule 3500 GPH Pump mounted higher than the two 900 gph regular bilge pumps.

I also plumbed the engine intake so I could throw a valve and be pumping through the engine. That would add about another 1500 gph to my pumping capacity. The engine pump was only 1-1/4”. If your pumps are bigger, you’re talking some real water. It’s easy and cheap to do.

Yeah, I know, I’ll ruin my engine. Who cares? The damn boat is sinking!

If you choose to carry an engine driven pump, I suggest you convert it to propane. The pump is a lot more likely to start after sitting unused for months.

In the North Pacific the Coast Guard often air drops pumps to boats that would sink without the pump.

"I have an Edison portable manual pump."

Yes,

Its normal duty is to empty the waste tank , but hoses are long enough for emergency bilge , or even dink pumping.

Working in the salvage business and seeing actual water flow from all the different pumps.....

Taint nothun like a trash pump.....

That said, 4 well installed (wiring, lift, discharge run, etc) 3000 gph electric pumps are pretty impressive too.

The problem is most installed electric pumps rarely meet their potential capacity.

While pumps may provide more time to execute damage control..... the goal in any sinking is to reduce flooding to below pump capacity. Stopping the flow isnt necessary.

I have added over years several additional electric pumps. The two new 3700 Rules can move a lot of water. I opened the sea cocks and tested them.

Back in 1970, a real pathetic OEM design was using three small 500gph pumps using 3/4 " hoses, one was a shower sump. I upped to two Rule 2000's, two Rule 3700 and another Rule 500 and when I repaired the shower sump went to 300 gph, it pumps much better now.
One of the Rule 3700 is never wet, it is raised up to be more of an emergency pump. My boat never just pumps from a leak, but it can get rain water inside.

So I have 6 Rule pumps. I also divided the boat by sealing the bulkhead wall dividing Lazarette and the main bilge. So if something happens back there it will only flood the rear half of the boat.

All those pumps simply lessen the odds of it sinking but dont prevent it from sinking. My thinking was the boat statically in the slip is not at high risk of sinking, it is more at risk when we are using the boat and say I break open the hull by hitting something.

Four watertight compartments, at least below deck level. Each compartment has 2000gph pump. "Should" be able to flood any compartment without it flooding into the next. Have not tested that feature, but that is how I designed it.

Two pumps are on one batt bank, two on the other.

I don't think additional pumps would be much of an advantage.

Ski in NC said:

Four watertight compartments, at least below deck level. Each compartment has 2000gph pump. "Should" be able to flood any compartment without it flooding into the next. Have not tested that feature, but that is how I designed it.

Two pumps are on one batt bank, two on the other.

I don't think additional pumps would be much of an advantage.

Click to expand...

I tested my aft sealed 'watertight' bilge compartment by disconnecting a thru hull for the heat pump for an hour. At first the water was gushing in, then as it filled it slowed till finally was just trickling in, the rear of the boat sunk about 5 inches until it almost stopped coming in. It took quite a while to pump out all that water. My goal was to simply slow down water ingress, so the pumps can keep up.
And I examined the other side of the bulkhead and it was basically dry. I don't consider it a safe test, I did not want to precipitate anything worse or flood my generator, so I quit the sinking test. The only thing I dont like about sealing the bulkhead is it now holds water back there which used to drain all the way forward. So I added a small 500 gph pump right next to the bulkhead wall which helps get out some of it after it rains.

The poll does not quite work I have several of the options not just one

On ships the water is seldom lifted , as that takes immense power.

Instead the bilge pump has an underwater discharge .

Might be a bit of engineering on a small boat ,
but if you want that 2000GPH pump to do better than 500GPH actual, it might be worth a thought.

Would take a helluva pump running through a helluva check valve (since you wouldn't want to be down there throwing a seacock open) to accomplish that. You'd still need it to run through a vented loop.

caltexflanc said:

Would take a helluva pump running through a helluva check valve (since you wouldn't want to be down there throwing a seacock open) to accomplish that. You'd still need it to run through a vented loop.

Click to expand...

Those plastic well water check valves come in large sizes.
They do very little restricting of the flow for well pump suction.
Thing is, how would you know the check valve closed when the pump shuts off, could be risk of sinking if debis was caught in it. Unlikely to get debris that big, those valves clear themselves of smaller debris. But your risking a sinking.

HopCar said:

One of my favorite subjects, said the man who’s boat sank.
The pumps are there to buy you more time to plug the leak or for help to arrive.
The more pumping capacity, the more time before you have to swim.

I was once on about a forty foot sport fish. We had been backing on a large fish for a long time and a lot of water had come aboard and gotten below deck. We eventually noticed water was coming in the freeing ports, not going out. There was only two Rule 1500 bilge pumps aboard. It was touch and go for a while and I considered cutting the engine intake hose at the seacocks which were about a foot underwater. The Coasties arrived with a 3” gas pump that turned the tide. (Turned the tide, I like that!)

On my own boat I had installed a Rule 3500 GPH Pump mounted higher than the two 900 gph regular bilge pumps.

I also plumbed the engine intake so I could throw a valve and be pumping through the engine. That would add about another 1500 gph to my pumping capacity. The engine pump was only 1-1/4”. If your pumps are bigger, you’re talking some real water. It’s easy and cheap to do.

Yeah, I know, I’ll ruin my engine. Who cares? The damn boat is sinking!

If you choose to carry an engine driven pump, I suggest you convert it to propane. The pump is a lot more likely to start after sitting unused for months.

Click to expand...

Well said. I'd add that sometimes it takes awhile to get to the leak as well, and even a two inch hole can let in a prodigious amount of water.

I installed a 250 gpm hydraulic Pacer pump with pickups in each water tight compartment. The hydraulics are powered by either the main or the genset. Since I had the luxury of starting with an empty boat this wasn't an expensive system, and I am surprised more manufacturers don't make accommodation for something similar. I use the same system to pick up raw water to discharge through a fire hose.

FF said:

On ships the water is seldom lifted , as that takes immense power.

Instead the bilge pump has an underwater discharge .

Might be a bit of engineering on a small boat ,
but if you want that 2000GPH pump to do better than 500GPH actual, it might be worth a thought.

Click to expand...

I don’t think the danger and complications of an underwater discharge are worth it. The Rule 2000 is still moving 1300 GPH with 6 feet of head.

HopCar said:

I don’t think the danger and complications of an underwater discharge are worth it. The Rule 2000 is still moving 1300 GPH with 6 feet of head.

Click to expand...

Yes indeed, and for safety's sake you still have to run the output hose above the maximum heeling waterline to form the loop anyway. At that point you might as well shoot it out the side above the waterline.

caltexflanc said:

Yes indeed, and for safety's sake you still have to run the output hose above the maximum heeling waterline to form the loop anyway. At that point you might as well shoot it out the side above the waterline.

Click to expand...

Don’t forget you need a vent in the loop or there is danger of starting a siphon and sinking the boat.

Yes, that's why I specified a vented loop in my first response.

caltexflanc said:

​

Yes, that's why I specified a vented loop in my first response.

Click to expand...

So you did. Post 16. Sorry I missed it.

FF said:

On ships the water is seldom lifted , as that takes immense power.

Instead the bilge pump has an underwater discharge .

Might be a bit of engineering on a small boat ,
but if you want that 2000GPH pump to do better than 500GPH actual, it might be worth a thought.

Click to expand...

Actually it takes virtually the same power to pump the water up 100 feet to surface rather than discharging underwater at 100 feet depth.

The only difference in pump discharge pressure (if both are sea water) would be due to a small mount of pipe friction going to surface. ( 1or 2% if the pipe is sized correctly)


I suspect the reason ships discharge underwater is because it is cheaper, and avoids running all that steel pipework to surface.

Delfin said:

Well said. I'd add that sometimes it takes awhile to get to the leak as well, and even a two inch hole can let in a prodigious amount of water.

I installed a 250 gpm hydraulic Pacer pump with pickups in each water tight compartment. The hydraulics are powered by either the main or the genset. Since I had the luxury of starting with an empty boat this wasn't an expensive system, and I am surprised more manufacturers don't make accommodation for something similar. I use the same system to pick up raw water to discharge through a fire hose.

Click to expand...

Define not expensive?
Reason I ask is being an ex trawler we have a substantial hydraulic system onboard and since becoming a pleasure boat the only thing working off of it is the rudder.

Add. Is this what you have?
https://www.ebay.com/itm/Pacer-Pump...658?_trksid=p2349526.m4383.l4275.c10#viTabs_0

Very bloody reasonable if all I need to do is run some hydraulic hose
High pressure anchor wash sorted.

AusCan said:

Actually it takes virtually the same power to pump the water up 100 feet to surface rather than discharging underwater at 100 feet depth.

The only difference in pump discharge pressure (if both are sea water) would be due to a small mount of pipe friction going to surface. ( 1or 2% if the pipe is sized correctly)


I suspect the reason ships discharge underwater is because it is cheaper, and avoids running all that steel pipework to surface.

Click to expand...

And of course the fact that ships typically do not discharge bilge water intrusion underwater to begin with.