Tapping into Engine Cooling Water Line for Galley

[Weyalan]

We are installing a salt water faucet at the galley to help preserve our limited fresh water supply.
I’m not a fan of drilling any more holes in the boat than I have to, especially below the waterline
I am therefore considering tapping into the cooling water">engine cooling water line by insering a t-piece just behind the inlet ball valve.

The salt water pump is a simple manually operated (foot pump) so the draw is negligible, so I am not worried about “starving” the supply to the engine.
I am concerned, however, that I may introduce a way to suck air into the engine cooling water (although the engine is fresh-water cooled via a heat exchanger).
If I put a ball valve in the line to the pump, will the system be ok, or am I taking too much of a risk tapping off the engine cooling water?

Thanks for your advice.

[JPA Cate]

Hi, Patrick,

I answered you a bit ago, but the post has disappeared. Jim did exactly what you propose to do to I-1, and we never had a problem with diminished flow to the engine that we were aware of , nor was their an airlock problem. It saved us huge amounts of fresh water.

Ann

[Weyalan]

Originally Posted by Ann T. Cate

Hi, Patrick,

I answered you a bit ago, but the post has disappeared. Jim did exactly what you propose to do to I-1, and we never had a problem with diminished flow to the engine that we were aware of , nor was their an airlock problem. It saved us huge amounts of fresh water.

Ann

Thanks for your input Ann. Your post didn't disappear... I couldn't decide whether to pose the question in the Engines and Propulsion section or the Plumbing section, so I posted in both... and you originally answered in the other one! Sorry for any confusion

[chala]

Originally Posted by Weyalan

I am concerned, however, that I may introduce a way to suck air into the engine cooling water (although the engine is fresh-water cooled via a heat exchanger).
If I put a ball valve in the line to the pump, will the system be ok, or am I taking too much of a risk tapping off the engine cooling water?

Thanks for your advice.

So long you do not forget to turn off the valve it should be OK. I do not know about a foot pump but with a hand pump it is very hard to draw some water when the engine run at 2200 rpm. A deck wash pump will definitely reduce the flow of coolant to the engine.

[Tellie]

A fresh water cooling pump can create a good vacuum when running. I have no idea if that would affect this foot pumps internal parts or whether there would be any air ingress through the cooling pump reversing the pressure through the foot pump that was designed for flow in the other direction thus affecting the engines cooling capabilities. You would think if it is a good tight plumbing seal that there would be no issues. But just thinking out loud, I would think as a precaution I would consider a one way check valve as well somewhere between the "T" and the foot pump.

[boden36]

I did a similar thing but was concerned at the possibility of sucking air back into the system. Installed a ball cock in the line which we close if on a long run.
Regards,
Richard.