Suction Salvage

[xort]

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.

[hellosailor]

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)

[JohnRPollard]

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

[Valiente]

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.

[sailingdog]

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.

[tomaz_423]

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.

[hellosailor]

"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.

[Omatako]

Originally Posted by hellosailor

"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

[sailingdog]

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.

Originally Posted by hellosailor

"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.

[Valiente]

Originally Posted by tomaz_423

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.