My crash pump idea

[Zach]

Mine will be getting a Jabsco belt driven bilge pump once I figure out how I want to mount it.

I'm planning to replicate this installation: Engine-driven Bilge Pump

They double as a washdown and fire pump, with a big honking impeller. Working in a boat yard, means you get to see what happens when you hit something when underway. The fish boats, with big raw water pumps and matching washdown pumps that run continiously have a crying chance. Pleasure boats, not so much.

Zach

[dstrout]

Just to follow this up, I ended going with the 120V option. Looking at the specifics of the whole picture (boat, money, crew, time, etc, etc), a 120V pump made the most sense for us.

What we settled on is actually a high-volume koi pond pump called the Alpine Cyclone 8000. It's got 2" NPT threaded inlets and outlets, is fairly compact, is submersible, and has a silly-long cord on it.



It's rated for roughly 6400 GPH at 5' head.

Video with a 5' lift and 5' run attached.

I'm not sure if I am allowed to post direct links or not, but my blog below has a bit more info.

That install is on hold until I find an oil leak that is dripping into my lower bilge, but as soon as I do, finishing the install of the crash pump is next. I'll post follow ups as it goes along.

[S/V Alchemy]

If you have more water than that coming in, it may be time to consider the raft!

Good video, thanks.

[dstrout]

Originally Posted by S/V Alchemy

If you have more water than that coming in, it may be time to consider the raft!

Good video, thanks.

Well, I actually have room forward to tuck a second one under the floor. I'm going to get the first fully installed, but two would be very happy.

"If its worth doing, its worth over-doing"

[Dockhead]

I studied this and came to the conclusion that a large AC electrical submersible trash pump is the best emergency dewatering pump. Provided you have an appropriate power source (not just an inverter which could get flooded). No need for permanent installation; just use a folding hose, which you can run out the companionway. That way you can also use it to save someone else's boat.

Ability to pass solids is a key quality - hence trash pump. Flooded bulges are always full of all kinds of carp which will clog ordinary pumps.

[dstrout]

Completely agree, and that's where I started out. My problem was that I only have an inverter, and the startup current of a real trash pump was beyond what I could handle.

The pump has a 2" NPT fitting for the intake behind the cheap little grill cover. I plan to take a 2' piece of 2" PVC, cut most of it away, and wrap it in 1/4"-opening mesh. I can thread that on and just leave it in place.

Granted all of this is a bit of a hack. I look at it this way. There is a continuum between a 220V 10K GPH 3" discharge sewage pump and my sad little Rule 3000. This is somewhere in between, it's probably better than nothing, and unlikely to be worse than nothing. If it runs for 6 minutes before it dies, that 800 lbs of water that isn't in my boat while I was busy stopping the leak. If it runs through the whole drama, WOOT!, If I never find out (my preference), double WOOT!

Ideally, I'd go with a dedicated inverter tucked up in a very high corner somewhere, but I need to get the rest in place first. A dedicated inverter is an enhancement - I've still got a long list of other basics to deal with.

[ranger58sb]

Originally Posted by dstrout

I've been thinking about this for a while, but it so happens that the guts of my boat (1985 Tashing Baba 40) that now would be an easy time to install a crash pump. Before I spend $300 having missed something obvious, please poke holes in the idea.

Whether you proceed or not...

Does your main engine (diesel?) have a water pump? If so, it's relatively easy to configure a T-function in your raw water inlet, so the engine can suck from outside or from your bilge. Groco sells relevant valves and strainers... probably other's do, too...

If that could work, it could be another way to solve it... or it may give you more leeway in design of an augmentation system...

-Chris

[Horror Hotel]

Engine pumps move very little water compared to what the OP is talking about. What I don't like about it is it's not wired to a permanently mounted generator. It you need the volume of the pump, even several minutes of set up is to much. And if it's rough out ( when disaster happens) your gen set up might not happen at all . I have my eu2000i bolted down, plugged in, hooked to a water separator and 6 gallon tank. One pull and it's on. I could see an electric pump being more useful in my scenario as it's all set asides from one yank on the cord. If you need 8400 gals an hour, any set up is too much .

[denverd0n]

Originally Posted by dstrout

It's sort of like the theory that we are all dying. The goal is to do it as slowly as possible.

Good point.

[Terra Nova]

Originally Posted by dstrout

...Run a 2" vented loop as high as I can and then back down to a thrihull just above the waterline...

Dave--think about this--that thru-hull will be way under water by the time you get a crash pump running. No need for a vented loop. Just place the outlet high on the hull and as close to the pump/pickup as possible; keep the run as short as possible. An in-line ball valve can be added and placed within easy reach.

Besides convenient manual electrically operated pumps, an engine driven pump is desirable. I installed the Erickson pump on a Mapleleaf 50.

[dstrout]

actually i've already got the wiring done to have it permanently hooked to the inverter controlled by a covered toggle switch next to the companionway. I'm looking at this as built in, not portable, even though it could be. I want as close as I can get to instant availability. If its in the bottom of the lazarette covered in crap because no one has touched it in a year, its no good to me.

[HopCar]

Horror Hotel,

Don't be too quick to dismiss the engine cooling pump. Chris has what appears to be a pretty good size power boat. I bet he's got two engines with 2" pumps that will move a lot of water.

You're right when it comes to most sail boat engines. They're usually only 3/4" and will only move about what a very small Rule bilge pump would move.

[Horror Hotel]

Very true, I was thinking sail vessel, even a big one won't have good engine pumps to clear a fast filling bilge.

[Horror Hotel]

A power boat with a couple 300hp cats maybe worth it, most sail boats under 100hp, not gonna help compared to a 8400 gal per hour electric pump.

[cal40john]

Originally Posted by Terra Nova

Dave--think about this--that thru-hull will be way under water by the time you get a crash pump running. No need for a vented loop. Just place the outlet high on the hull and as close to the pump/pickup as possible; keep the run as short as possible. An in-line ball valve can be added and placed within easy reach.

Besides convenient manual electrically operated pumps, an engine driven pump is desirable. I installed the Erickson pump on a Mapleleaf 50.

Head is determined from inlet to outlet. The lower the outlet the less head and the faster a centrifugal pump pumps. I forget the term but there is another head which is how high the pump can lift water with none in the downhill part of the hose. This determines how high the top of the loop can be.

Originally Posted by Dockhead

I studied this and came to the conclusion that a large AC electrical submersible trash pump is the best emergency dewatering pump. Provided you have an appropriate power source (not just an inverter which could get flooded). No need for permanent installation; just use a folding hose, which you can run out the companionway. That way you can also use it to save someone else's boat.

Ability to pass solids is a key quality - hence trash pump. Flooded bulges are always full of all kinds of carp which will clog ordinary pumps.

I think you have to be careful with folding hose. Centrifugal pumps are sensitive to backpressure, and you could decrease flow significantly. A friend tried to use something similar to firehose on a Rule 8000, the flow was unimpressive.