Crash Pumps?

[Captain Jeffry]

Great discussion. All ears! Anyone ever heard or tried the main engine raw water intake hose for dewatering assist? Urban legend?

[maxingout]

I always carried a whale gusher bilge pump mounted on a board that I could move around the boat to pump water in the event of a serious but non-catastrophic leak.

I think water tight bulkheads would keep my boat from sinking until I could patch the hull. Then the moveable high capacity manual bilge pump would have the job of pumping the compartment dry.

[DeepFrz]

How much water comes out of your exhaust in a minute?

[cal40john]

Originally Posted by DeepFrz

How much water comes out of your exhaust in a minute?

I measured 2 GPM on my 3GM30, assuming linear output about 8 GPM at near max rpm. Not going to bother with mine.

John

[Nicholson58]

Originally Posted by atoll

having 5 watertight bulkheads,and a jabsco high volume clutched pump off the front of the main engine gives a lot of pieace of mind,the main engine will run under water with the raised air intake snorkel/air filter assembly.
also a 240 v submersible,and 24v system trough a set of bellows and valves takes of care of the different compartments

when we cracked the skeg 3 days from antigua,the aft cabin flooded under the floorboards but was easily controlled by the 24v system,and could only rise to the water line level about 3" under the cabin floor in that compartment.

Sounds a lot like our equipment. Camper & Nicholson 58; 115 HP diesel with belt driven crash pump 100 gpm clutched to the main engine; Raw water inlet sea cock has a bypass plug to permit the engine to cool using bilge water; 115 VAC pump powered by the gen set; 24 VDC Rule 60 gpm primary. Also, hand operated Whale and I keep two pre-wired spare 24 VDC pumps as spare. The gen set is located chest high so it is the last to die.

You might also consider a pool pump (plastic and Stainless) as a high volume de-watering pump. Keep the motor oiled and bagged until you need it. They are really light weight. Most are self-priming as well by filling the strainer basket ahead of the intake. (NOTE: comes with an easilly cleaned strainer.)

I read several reports on Bounty btw. Together, the gist of the events sounded like a bilge pump was not performing adequately. Wood vessels of this type and size naturally have a large water flow to the sewer. Perhaps the flow was worse with the sea conditions. The pumps could not keep up and the generator and engines were flooded out. I am sure we will learn more. I also heard that at last sighting, the mast tops were still visible so perhaps the vessel can be salvaged. Hope the captain is saved. One loss is too much. I shared coffee with several of the crew in Green Bay in 2010.

[bobconnie]

I was lucky when I bilt our Colvin, and found a tranny with a power take off plate! From this I hooked up a 2 1/2 in pump, suction side, 3 in discharge side, will pass solids up to 1 1/2 but rags and stuff like that will stop her dead ! so had a big screen filter on the suction hose (solid hose) and had 3 inch flat hose for the discharge. Start the main pull the PTO handle, rev up the main and pump some water !! And there are many PTOs out there for the front of many types of engines, to hook up a disaster pump !! Never had to us it but tested it every once in a while !! Made a hell of a fire pump !! LOL

[HopCar]

"A word of warning - NEVER use your main engines water pump as a bilge pump!!!! The pump WILL get clogged up and you will overheat/damage your main engine. I have seen it happen a number of times - MAJOR dumb idea."

If your boat is sinking it's a major dumb idea not to use every available pump. Properly rigged the bilge water will have to pass through two strainers before it gets to the pump. It wouldn't hurt to clean your bilge once in a while either. If the bilge is so dirty it will stop your engine, it will stop all your other pumps as well.
I hope I never have to use it but I like having the option of using my engine pump.

[Bash]

Originally Posted by Captain Jeffry

Great discussion. All ears! Anyone ever heard or tried the main engine raw water intake hose for dewatering assist? Urban legend?

I once crewed on a large (110'+) motor yacht that had such a system built in. This boat had two 12-cylinder Detroit diesels bolted together on each screw. It could suck major amounts of water out of the bilge in a short time, just by flipping two levers.

I looked into such a system for my sailboat, but opted not to go with it because the engine cooling system doesn't circulate sufficient water. A large-capacity secondary emergency 12v bilge pump, mounted above the working pump with a 2" outflow, does a superior job for less money. Make certain the emergency pump is alarmed.

[Dockhead]

Originally Posted by Cheechako

Yeah, 30 gpm is a little over a 55 gallon drum every 2 mins... that's a lot of water compared with your average bilge bump... whatever it's "rating".

Agree that bilge pumps tend to be unrealistically rated, as real flow goes down quickly with head and resistance. But I think they still mostly pump well over half of their rated capacity in real conditions. So my 3500 gph Rule crash pump should shift at least 30 gpm, probably 40 or 50, discharging through a plumbed-in 2" hose. So a 30 or 50 gpm-rated water pump, with no solids-handling ability, is not going to add much - it's more less the same as what I already have, and with the same main weakness - proneness to clogging. I want a real high capacity trash pump which will chew up and spit out the crap which will inevitably be floating in the bilge if the water gets up. 150 gpm or so sounds good.

If my main engine is running, then I will have DC power. So I don't care much about an engine-driven pump (and anyway, I have two alternators, so hardly any room for an engine-driven pump). And I would never use my engine cooling system to pump water from the bilge - yikes. It clogs, then you've got an overheated engine on top of all your other problems. No thanks!

If my main engine is dead, there's a good chance my genset will still work - it's located high above the waterline, and has totally independent starting battery and wiring.

[estarzinger]

just fyi . . . pic of bounty engine room. They main pump is the green item in the right foreground. It's a hydraulic centrifugal industrial pump, powered by a PTO on the genset. It looks to have a make shift intake hose that is probably restricting its flow.

Note: fuel filter set up in the background left.

[micah719]

That's the main pump, eh? How big was this wooden ship?

[Captain Jeffry]

The HMS Bounty, big~

[Captain Jeffry]

estarzinger...

Great home blog and love the Hawk.

[hellosailor]

See there's the problem, they used landlubber gray basement paint instead of white marine paint. Velly bad juju.

[Boracay]

I'm planning on going the other way.

I have an Rule pump high up in the bilge and a whale manual pump that sucks from way down. The small amount of water that gets in I take out with a vacuum cleaner.

I can't see it being worth the trouble and expense of installing a crash pump. Better to spend the money on keeping thru hulls/seacocks up to date and making sure all life saving gear is up to the job. Which, from all accounts, is what they did on the Bounty.

If I had to install any emergency leak equipment I'd go for an ap. connected to a float switch so I got a phone call if the water started to rise. As it is I'm relying on concerned neighbours and an alert marina management.


Of course I could arrive at my boat at Christmas and find it sitting very low in the water...

My take on the Bounty is that they got some very big short steep seas, and that heavy engines in an old wooden boat did the rest. I don't think a crash pump would have saved them.