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Discussion Starter #1 (Edited)
I am currently reading One Hand for Yourself One for the Ship: The Essentials of Single-Handed Sailing by the experienced (over 400,000 miles) late cruiser Tristan Jones. It is a great read and a must add to our on board library. I just today read about salvage suction in Jones' book, however a couple days earlier I read about it in this months Sail Magazine in an article by Martin Becker, who says he learned about the concept in a Power Squadron Seamanship course.

Very simply put for those who don't know salvage suction is just simply utilizing your engine as an extra bilge pump. Your engine is constantly sucking in raw seawater to cool itself. Install a Y-splitter piece on the engine end of your raw water hose (The other end should be connected to a seacock). Once the splitter is installed connect other end of the piece of hose that has one end connected to the seacock. Connect another hose to the available fitting on the splitter and lead the bitter end to the depths of your bilge.

So God forbid if you find yourself taking on more water than your bilge pumps (notice I said pumps you should always have more than one automatic, and manual) can handle, you can close the seacock hose off at the splitter and the engine will utilize the water that has been filling the bilge. This may give you sufficient time to sufficiently stop the leakage, run aground, or safely abandon the vessel.

Most of you probably already know this however I have only been sailing for a couple years now, and thought fellow greenhorns might want to know this valuable piece of information. It could potentially save your boat, your person and crew.

-Spencer
 

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Spencer,

Yes, that is a mod that has been discussed off and on for a fair bit. No harm in bringing it up again here, though.

A lot of folks feel differently about that approach. Most engine raw water pumps do not handle debris very well --hence all the strainers, etc. So they would easily jam up if any debris came up from the bilge. Even a clean, ship shape bilge is likely to get fouled by debris in an emergency flooding situation -- bits of paper that go mush, particulate matter flushed by flooding waters from obscure crevices, etc etc.

So if you took that approach, it would be important to install some kind of strainer on the end of the hose led to the bilge. But even with that precaution, some feel it's not worth losing your engine to an overheat situation just when the situation is most dire. Others argue that if the alternative is losing the boat to sinking -- who cares?

But there is no argument with the claim that nothing will pump water like a diesel engine. That's why many marine engine manufacturers offer a separate option for a dedicated emergency pump, that mounts to the block much like an alternator and which is belt driven from a PTO. These pumps are designed to move higher volumes of water and are much less prone to fouling from debris.

If I ever felt the multiple electric and manual bilge pumps were not enough, that's the approach I'd take. But "suction salvage" might be a good last ditch option for some.
 
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I was thinking that way too long time ago.
I was also thinking to rig shower drain pumps to empty the bilge (have 3 on my boat). I now think it is not worth the trouble.
Look just how little water comes from the exhaust.
That little you would suck from the bilge.
My guess: not worth a hassle. Buy one size bigger bilge pump, problem fixed.
If the leakage is small any pump will handle it, if the leakage is large (missing shaft, broken sea ****, hole from hitting a container ...) no pump will be able to save your boat.
For that few percents flow increase I would prefer not to risk the engine - you might need it to produce electricity for bilge pump(s).
I would rather invest my energy and time in methods to divide the boat into separate watertight sections, into faster finding the holes and methods to fix the leaks.
 

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Not really a good idea IMHO. If you manage to screw up the raw water intake or impeller, you'll have no engine. No engine means no alternator, no battery charging, no electric bilge pumps. Considering how little water the engine cooling system actually pumps, there really isn't any point to doing this.... you're much better off getting a second or third high-volume, electric bilge pump, which will pump a lot more water out of the boat than the raw water system of the engine, and not run the risks of trying to empty the bilge with the raw water cooling system.

If you're really worried about it, buy a separate diesel dewatering pump or setup a dewatering pump on an electric clutch on your engine.
 

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Everything that's old is new again? Except the term "salvage suction" appears to be a shiny new moniker.

sd, if you are flooding and all the pumps on the boat aren't keeping up with the water--that's the time to use the engine's water pump and it you lose the engine, it doesn't matter, you are about to sink anyway.

John, the "strainer" would be a strum box. Strainers are for pasta, strum boxes are for bilge pumps. I think I last bought one just short of four years ago, I'd guess they are still being sold commercially. We could have used bronze screening over the hose end, but we chose to go hog wild and splurge on a commercially built part that could be screwed down in place, too. (G)
 

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My boat has twin heads. Each head has a shower and each shower drains into a reservoir in the bilge where it is pumped out by an automatic bilge pump. The reservoirs are not sealed units, just plastic boxes with the pipes and electics connected as required.

So if the flooding became more than my electric pump could handle, I would switch on both the shower pumps and double (I reckon the pumps put out about half what my bilge pump does each) the pump-out rate. I reckon that would afford me some time.

But I agree, the last thing I would want is that the engine extracts water quicker than expected and cooks the motor. A high rate leak doesn't guarantee that the boat is doomed, why lose the engine at the same time as trying to fix a serious leak?
 

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...John, the "strainer" would be a strum box. Strainers are for pasta, strum boxes are for bilge pumps. I think I last bought one just short of four years ago, I'd guess they are still being sold commercially. We could have used bronze screening over the hose end, but we chose to go hog wild and splurge on a commercially built part that could be screwed down in place, too. (G)
HS,

Thank you for the correction on the proper terminology.:) I like that term "strum box" -- it sounds almost musical. Just to be clear, the correction goes to my second reference to "strainer", and you have no objection to the first usage in relation to the engine raw water intake strainer?

I take it your "strum box" was for a conventional bilge pump, not a "salvage suction" arrangement?
 

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You could just pickup an old jet ski for 100 bucks and stuff the drive components in the bilge in an emergency. At full power itll pump about 6000gpm. You just need to maintain 8000rpm.
 

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My boat has an electric bilge pump, a cockpit manual bilge pump and also a manual pump mounted over the engine. Don't like that, mounted over the engine seems like a bad idea. I'm thinking of rerouting this pump and changing from manual to electric. I'm pretty sure all three use separate discharges.
Thoughts?
 

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Discussion Starter #10
I think my point is being mistaken. This is only to be used in a dire dire emergency. AKA you losing your 50,000 dollar boat plus your 20,000 engine! And not to mention your invaluable life! If you do break your engine whilst in salvage suction and buy enough time to temporarily install a collision mat, bung, etc., then you should be able to sail back home alive and have a $20,000 repair rather than a $70,000 loss and potentially a invaluable loss; your life!

I like the idea about utilizing the head and shower pumps I never thought of that.

-Spencer
 

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I don't think your point is being mistaken.
You could be in a dire emergency, use the engine to pump the bilge and clog the engine with bilge junk. You'd be in worse condition because now you have no engine to add to all your other problems. And the engine provides 12 volt for the pumps and radios.
 

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John-
"and you have no objection to the first usage in relation to the engine raw water intake strainer?" No objection, and just trying to keep an old word alive not meaning to be pedantic or anything. As long as your engine doesn't suck raw water from the bilge...or you don't sail in a bilge (G)... the raw water intake strainer is always a strainer, never a strum box. Dunno why, maybe it is to confound partially deaf highway robbers. "Where's the gold?" "In the strum box, down there." Yathink? (G)
 

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Nah, I didn't think you were being pedantic at all. Sailing is full of terminology, and I'm always eager to expand mine. :)
 

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Strum box...haven't heard that in a while, although they are still a good idea. There's another term that isn't "sea chest", but contains the word "chest" that we might term a 'water manifold' today. That's what you get for reading a bunch of cruiser tales from the '20s to the '60s: a load of obscure sailing terms!

The Y-diverter idea on the engine intake is indeed a last ditch thing I would prefer to avoid, but it has its place as a way to winterize the raw water circuit by shutting off the seacock and putting a hose in a bottle of antifreeze. I do this with my Atomic 4, although I have to remove the thermostat and "top up" as it won't open in the 90 seconds it takes to drain the bottle, even if I pinch off a hose.

The PTO is the way to go for emergency bilge pumping, if only because it's possible to lose the 12 VDC at some point while still having the engine operating, and a PTO will run a purely mechanical pump very well.

I have a Rule 3700 for the main bilge aft of the engine (a deep well), a biggish Patay bulkhead-mounted manual pump, and a diverter for the Henderson manual pump in the head. I will be installing a second large capacity 12 VDC pump before we go, and a shower sump pump system of the very style that Omatako endorses.
 

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HS—

Given how many GPM an engine's raw water cooling pump actually uses, there really isn't any point in rigging it and risking the engine on most sailboats. A 300 HP diesel might more a significant amount of water, but the 10-30 HP engines on most small sailboats don't move enough to be worthwhile.
 

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It looks that many people agree with my post no. 3.

Best confirmation that it makes no sense is this data from Valiente:
"90 seconds it takes to drain the bottle".
Let us say a bucket is 5 bottles.
So your engine suction system will do equivalent of 8 buckets per hour (or one bucket every 7:30 min.
So, you can forget it.
Even in 10 hours that is 80 buckets more water. This makes no difference (perhaps an inch more immersion)
But if it kills your engine then you loose alternator.
With alternator running you have about 13V on the bilge pump.
Without alternator you have maybe 12 V.
Pumping capacity increases or decreases a lot with that difference in V (for sure more then one bottle every 90 seconds.
 

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"Even in 10 hours that is 80 buckets more water."
If I was bailing by hand with a bucket, I'd still appreciate an 80-bucket break from the job.(G) Even it was only once every ten hours.

What part of "in an emergency" is still unclear? Or does everyone think an inconvenience and an emergency are the same thing? Two feet of water in the boat, that's a damned inconvenience. Two feet and still rising and all pumps still running--that's looking more like an emergency.
 

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"Even in 10 hours that is 80 buckets more water."
If I was bailing by hand with a bucket, I'd still appreciate an 80-bucket break from the job.(G) Even it was only once every ten hours.

What part of "in an emergency" is still unclear? Or does everyone think an inconvenience and an emergency are the same thing? Two feet of water in the boat, that's a damned inconvenience. Two feet and still rising and all pumps still running--that's looking more like an emergency.
That's looking like a time to check the batteries on the EPIRB and get the life raft ready :)
 

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Another electric bilge pump and not using the engine would do a lot more than a mere 80 buckets worth... and not risk you losing the engine when you may need it most. No engine—>no alternator—>no electricity to recharge batteries and power bilge pumps... while it sounds like a good idea, in reality it is a rather foolish one. Carrying another high-volume bilge pump and being able to power it makes much more sense.

"Even in 10 hours that is 80 buckets more water."
If I was bailing by hand with a bucket, I'd still appreciate an 80-bucket break from the job.(G) Even it was only once every ten hours.

What part of "in an emergency" is still unclear? Or does everyone think an inconvenience and an emergency are the same thing? Two feet of water in the boat, that's a damned inconvenience. Two feet and still rising and all pumps still running--that's looking more like an emergency.
 

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It looks that many people agree with my post no. 3.

Best confirmation that it makes no sense is this data from Valiente:
"90 seconds it takes to drain the bottle".
That's with the small accessory-drive Oberdorfer raw-water pump on an Atomic 4. But the Sherwood F-85 raw-water pump on my twice-as-large diesel is not radically larger (it's a very common pump), and I have no reason to assume that it would suck a wildly larger volume of water, just to judge by the hose sizes. So I think your calculations are correct: an engine cooling pump run off a small camshaft would only clear a small leak, whereas and higher volume electric pump with a 1 1/2" outlet, or a power take-off driven centrifugal pump, could clear water or debris-filled water more effectively.

I've even used a power washer to drain a bilge of clean water, because that pump moves far faster than a engine cooling pump could.
 
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