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3-way valve - raw water intake


freewheelin

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The former owner of my boat installed a bronze 3 way diverted valve after the seacock and before the raw water intake. He then ran a hose up through the cockpit locker, and attached it to the diverter. The point was (presumably) to be able to easily run antifreeze through the engine from the cockpit, rather than having to detach the hose down by the engine compartment. Could also be used to run the diesel on the hard more easily i guess.

In the fall when I went to winterize, I could not get the antifreeze to draw from the hose. I found out that the valve failed - so I had to cut out the system and did it the old fashioned way. Finally got around to inspecting the valve, and what happens is the handle turns, but the "ball" inside does not. I am not sure if that is a common problem. I can't tell the model of the valve, not sure if it is marine grade.

So I am at the point where I am looking to either reinstall a valve or forgo it and run the hose straight from the seacock to the strainer. In theory, I like the idea of the convenience and the hose to the cockpit locker is already run. But the valve failure has me freaked out. Had it failed the other way (raw water intake) it could have been a bad day with an overheated diesel.

Any advice? Anyone with experience with a similar setup. Any thoughts on a diverter valve that could be trusted?

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I have seen so many variations on this theme over the years... like you, I appreciate the theory and I want them all to work- we winterize over a hundred boats in the fall and it would save a bunch of time. Also like you, however, I find they fail more often than the convenience warrants.

The only systems that I have seen work reliably (and eliminate a ton of 'oh shit the valve is in the wrong position') are the systems designed to replace, either temporarily or permanently, the strainer cap. Those add a fair amount of convenience without disrupting your main engine cooling run, or at least disrupting it a hell of a lot less. I would probably recommend plumbing it back sans valve and look into one of the strainer cap systems IF you feel that it would be worth it in your setup and can find one that fits your strainer.

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Couldn't you just put a tee with an 'ordinary' shut-off valve of some sort on the antifreeze leg? When time to winterize you just close the thru-hull and open the new valve.

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I have also seen a 3 way valve on a raw water engine inlet used for any emergency bilge pump. The theory is that if you have major water leak or need remove a significant amount of water in the bildge you start the engine and then switch the 3 way valve over to the bilge and the engine will remove most of the bildge water. 

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  • 1 month later...

I had a 3 way valve and got ride of it.  If it fails you are stuck.  I re plumed straight to engine one valve one or off. I now pour the antifreeze into strainer unscrew plastic top pour in 2 gallons and I am good to go. Funnel helps too

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I have read about using the engine's raw water pump using a 3 way valve as a bilge pump a few times. The estimate is a typical small diesel pumps 2-3 GPM. As a back up to other options in a desperate situation I guess it might be OK, but as already mentioned the risk of overheating the motor when you need it most is a risk. In addition you need to factor in the valve and extra hose as additional points of failure. 

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On ‎5‎/‎16‎/‎2019 at 9:39 PM, steele said:

I have read about using the engine's raw water pump using a 3 way valve as a bilge pump a few times. The estimate is a typical small diesel pumps 2-3 GPM. As a back up to other options in a desperate situation I guess it might be OK, but as already mentioned the risk of overheating the motor when you need it most is a risk. In addition you need to factor in the valve and extra hose as additional points of failure. 

This is on nearly every large yacht I work on, the thru hull fitting is also an emergency bypass valve to use one or both mains to pump the water out really fast

Imagine a 4 inch bronze pickup with a 900hp MTU/MAN/CAT hooked up to it....

This is a Cabo, notice the one on the left,(starboard side of boat)

Cabo Engine room.jpg

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1 hour ago, IStream said:

What works for 900hp diesels isn't necessarily a good idea for a 30hp sailboat auxiliary.

Very true, I was merely showing a larger example of the same type of setup.

What do you recommend using in a 30hp sailboat?

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Like most everything, the answer is "it depends". The main factors are the shape of the bilge, the head height between the bilge and the exit overboard, and what you're trying to achieve. Is it nuisance water clearing or "oh shit, I'm sinking and I need to buy time" pumping? Oh yeah, and budget.

Jabsco has a good overview here: https://www.jamestowndistributors.com/userportal/document.do?docId=677

 

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On 5/17/2019 at 2:39 PM, steele said:

I have read about using the engine's raw water pump using a 3 way valve as a bilge pump a few times. The estimate is a typical small diesel pumps 2-3 GPM. As a back up to other options in a desperate situation I guess it might be OK, but as already mentioned the risk of overheating the motor when you need it most is a risk. In addition you need to factor in the valve and extra hose as additional points of failure. 

Our V40 had one of those, the valve leaked so there was water leaking into the bilge when the engine ran, and it also managed to suck air into the water strainer and stop the cooling water flow, I chucked it.

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