Emergency Pumping

[capngeo]

Originally Posted by MarkJ

I think I'd go for the sail over the hole first (or collision mat) and then worry about getting the water out.

Spot-on Mark! Pumps are for DE-watering AFTER the leak is stopped/slowed!

BTW, I keep a bunch of the plastic shopping bags you get from grocery stores these days..... I have stopped up 6" holes with them. They are free, store easily, never go bad, and are handy for other stuff too. I'll bet I have 500 of them on the boat mashed down into less space than ONE full bag!

[HopCar]

Ok we seem to be going toward fix the leak first then pump out. The original premise was that you needed to buy time to affect the repair. Let’s change it a bit. You’ve got your collision mat in place but water is still coming in faster than the pumps can take it out. You will sink before you can get help or beach the boat. You need to pump an extra 500 gallons per hour beyond your bilge pumps capacity to stay afloat long enough to save the boat. John, even the little raw water pump on your engine would come pretty close to that. I read your earlier thread on the subject, some good info there. Capngeo, I like the plastic bag idea. We all have some on our boats. Grab a handful, shove it into the hole and you’ve slowed the leak a lot. Bags might work on an irregular hole better than wood or Nerf plugs.
As for me, it’s so easy and cheap to rig my raw water pump as an emergency bilge pump it would be dumb not to. My engine has a 1-1/4” intake so it will move some water. I’d love to put one of those Erickson pumps on but I just don’t have the room. I will give some more thought to damage control supplies.

[Auspicious]

Originally Posted by HopCar

My engine has a 1-1/4” intake so it will move some water.

This comes up periodically. Some years ago I found a citation that a cooling water flow rate of about 15 gpm / 100 bhp for an indirectly (freshwater) cooled diesel (about 8 gpm for my 54 hp Yanmar 4JH4E). A Google search on shaft drive trash pump returned a bunch of options that include pumps with 2" to 3" inlets that will pass solids up to half the diameter of the inlet, run at 5(ish) hp from the main engine (or conceivably a generator, which may be mounted higher in the boat), and push 200 to 400 gpm. They aren't terribly large or expensive ($150 to $400).

Alternatively Honda makes a nice little gas-powered pump that weighs less than 15 pounds: Honda Power Equipment - WX10

[AllezCat]

I've been thinking about getting a real bilge pump.
Existing pumps (4 per hull) are for slowly emptying grey-water/light amounts bilge-water - and completely useless in an emergency.
I know enough about pumps to know about the pump curve - but no engineer.
So, I was thinking about buying (completely arbitrarily) the 1.5 HP swimming pool pump at Home Depot - mount in permanently(but easily mobile) manner so is plugged into 220v outlet from generator - flexible hoses with massive strainer - and can be moved if required. Can also be reversed for fire -fighting.
Those 37gazillion things don't appear very powerful/robust and would drop exponentially on the pump-curve as feet is increased over the zero it is rated at. The 1.5 hp has significant volume at many feet of head.
Sometimes holes can't be repaired at all or quickly - - and the pump can "hold water" till reaching safety, or until slowed or...not(you can't cover everything).
Maybe sea-cocks are very deep under water - etc I would want a pump that can keep up with/overcome a reasonable base-metric of water flow.
As far as massive to small hole from collision - not clearly definable. But what about blowing out a 1.5" sea-cock? - we all have them. Can the engineers define what the flow could be? Lets say at a certain draft/tonnage???
I would then spec a pump to suit.

[motion30]

The trash pumps are great and pump a ton of water but that engine sea water pump is already there I like that idea

[HopCar]

On the subject of big pumps, Rule makes a double 4000 GPH 12 Volt pump. That's 8000 GPH pumped out through a 3" discharge hose. Even allowing for loss of volume from discharge height, it's moving a lot of water. Rule 8000 > Rule Electric Submersible Pumps > ITT Flow Control - Engineered for life.

[cal40john]

Originally Posted by AllezCat

I've been thinking about getting a real bilge pump.
Existing pumps (4 per hull) are for slowly emptying grey-water/light amounts bilge-water - and completely useless in an emergency.
I know enough about pumps to know about the pump curve - but no engineer.
So, I was thinking about buying (completely arbitrarily) the 1.5 HP swimming pool pump at Home Depot - mount in permanently(but easily mobile) manner so is plugged into 220v outlet from generator - flexible hoses with massive strainer - and can be moved if required. Can also be reversed for fire -fighting.
Those 37gazillion things don't appear very powerful/robust and would drop exponentially on the pump-curve as feet is increased over the zero it is rated at. The 1.5 hp has significant volume at many feet of head.
Sometimes holes can't be repaired at all or quickly - - and the pump can "hold water" till reaching safety, or until slowed or...not(you can't cover everything).
Maybe sea-cocks are very deep under water - etc I would want a pump that can keep up with/overcome a reasonable base-metric of water flow.
As far as massive to small hole from collision - not clearly definable. But what about blowing out a 1.5" sea-cock? - we all have them. Can the engineers define what the flow could be? Lets say at a certain draft/tonnage???
I would then spec a pump to suit.

Read the thread I linked in post #8

John

[rebel heart]

Originally Posted by MarkJ

I think I'd go for the sail over the hole first (or collision mat) and then worry about getting the water out.

Agreed. No point in pumping water if it's flooding in faster than you can pump it out.

We have an Edson manual that will pump *a lot* of water. I think it's rated at 30 gallons per minute and you can keep it up for a long time. The pump handle is about four feet long so you just shift your weight back and forth to use it.

In Adrift Steven Callahan talks about the speed by which his boat went down. I think he said his decks were awash in under two minutes.

[AllezCat]

Originally Posted by cal40john

Read the thread I linked in post #8

John

Thanks
perfect data from that link:
so about 8000 or 4000 gph from a 2" hole at 3' depth -depending on the formualsss...
Something to start with.
And that is a pretty small hole compared to collision potential....
Any over the counter pump will not come within 10 or 20% of that at a realistic few feet head...
A 100-200HP engine has what flow rate in its raw water pump???
Probably not much for all that power...

And why compromise about doing one thing first and then another?
Flip the switch to start automatically pumping and attend to leak...

[AllezCat]

Originally Posted by HopCar

On the subject of big pumps, Rule makes a double 4000 GPH 12 Volt pump. That's 8000 GPH pumped out through a 3" discharge hose. Even allowing for loss of volume from discharge height, it's moving a lot of water. Rule 8000 > Rule Electric Submersible Pumps > ITT Flow Control - Engineered for life.

You should get the pump curve data and it will give you a very enlightening data on what the capacity of these pumps really is past the speculation, and marketing bs...when it has to (and must) pump up-hill - and run longtime.
A "lot", "heaps", etc doesn't mean anything...
I am looking at "real" pumps but they are ac...

[HopCar]

Allezcat, good point about the loss of volume with increased head. I couldn't find specifications on the Rule 8000 but Practical Sailor Magazine tested the Rule 2000. It delivered about 1300 GPH at one meter. Other things I've read lead me to believe that at 2 meters you are down to about 1/3 of the no head volume. That's about 2600 GPH on the Rule 8000. I like your idea of flip the switch and attend to the leak. In our scenario you don't have time to be rigging pumps. Get everything pumping that you easily and quickly can, then work on the leak.

[Pblais]

perfect data from that link:
so about 8000 or 4000 gph from a 2" hole at 3' depth -depending on the formulas.

Hitting a container at some speed there is no way to pump it fast enough with any pump you could power nor be able to close a water tight door that was not already closed. With a 6 to 8 inch hole on most boats she is going down before you can shove something over the hole from the outside to slow it down. Using the raw water pump on the engine sounds better than it will work. The flow rate isn't very much.

A water tight door already close could save the crew. The loss in boat maneuvering could be a serious issue on a long haul with bad weather and you could still lose the boat.

Once the hole is more than a few inches in diameter nearer the bottom your chances are quite slim in saving the boat. I would agree that anything you need to do needs to happen in the time period it takes to flip a switch. Monster bilge pumps take a lot of power. Your whole battery bank could be dead pretty fast with huge pumps.

I just replaced a distribution pump on our septic tank. The old pump was a 2 phase 40 amp pump running 220 volts. This is just a pump to move waste water that comes out of the 1500 gallon tank out of the second tank that is 1000 gallons to the drain field. To move the volume of water from a large leak really wants a commercial grade 3 phase pump. A 150 amp alternator on your engine just isn't up to that type of power requirement.

If the hole can't be blocked from the outside in minutes you could never last hours. Lasting days is not an option.

[James S]

If your sailing and heeled...and if the hole is on the leeward side, changing tack may have some effect on slowing the flow.
I wonder what impact booming out to the opposite side as the hole and and applying some weight to the end would do.

Also wonder how much impact dumping my anchor an 300ft of 3/8in chain would have....this seem minimal.
What about blocking the drains in my aft lazeret and then flooding it?

I don't single hand...but I'm thinking if I did, I'd start the engine and switch over my raw water valve to the bilge...my other two bilge pumps are auto....then I tend to the leak.

[conachair]

Easier solution, get a steel boat..

[thinwater]

Originally Posted by conachair

Easier solution, get a steel boat..

Or a cat with some good crash tanks and bulkheads fore and aft. I lost athrough-hull on a delivery trip once and I didn't even need to try to fix it. It flooded the compartment and probably lowered the waterline an inch. Crash tanks lend themselves to multihulls better because the bow and stern space is less usable anyway.

A rip exceding 6 feet in the wrong place could be a problem. A long rip was a problem for one steel ship I can think of.