SALT TO FRESH?

Don S/V ILLusion · Dec 23, 2018

How would one do that? And more important, why?

DayDreamer41 · Dec 24, 2018

Tank fed fresh water system?? what size tank would that have?? recirculated with some kind of cooling system?? whats the problem with a raw water secondary (primary being closes to the engine/heat source)??

Will Gilmore · Dec 24, 2018

rpell1,
I have no idea about anything to do with circulated cooling systems. By the responses above, it is very unusual to convert, as you are asking to do. I would assume you are considering moving your boat to a freshwater environment or maybe back and forth? Anyhow, if you are looking to convert to an enclosed circulated system like that, consider the added weight to the boat and for an enclosed system using freshwater, there is the issue of algae buildup. Maybe you could do as you want, but keep it salt-based?
Just some things to think about.

-Will (Dragonfly)

jssailem · Dec 24, 2018

rpell1@msn.com said:
converted the raw water portion of your cooling system to a tank fed fresh water system?

rpell1@msn.com said:
speculating how to eliminate salt (or worse brackish) water from running through my cooling system.

Ok @rpell1@msn.com.
Tell me a bit about your system.
Normally our engines have one or two systems. In days gone by...

System 1- pumped water into the engine from the surrounding water (which was expected to be cooler than air temp) into the engine. It was circulated through channels in the engine block and then expelled with the exhaust. It was a simple system but fraught with problems. In salt water and even in fresh water there was corrosion. Constant maintenance was required. And engines failed.
System 2 - Wise engineers discovered the idea of 2 water systems one closed loop and the other raw. The engineers further developed additives to modify the fluid in the closed loop system (gluten free antifreeze and water). The closed loop system would be run through the engine block heating up, then run through a "heat exchanger" to be cooled then back to a tank then back to the engine. Never would the closed loop solution be exposed to the raw dangerous world.
This system no needed to get the heat out of the "exchanger" so raw water was pumped into the exchanger. It ran through pipes next to the closed loop pipes and stole the heat from the engine. Then immediately was pumped into the exhaust pipe and tossed back to the sea. Pretty much no more corrosion in the engine.

And the sailors were happy again.

So my question is what part of this is not working in your situation.

Ron20324 · Dec 24, 2018

DayDreamer41 said:
Tank fed fresh water system?? what size tank would that have?? recirculated with some kind of cooling system?? whats the problem with a raw water secondary (primary being closes to the engine/heat source)??

And where would you put the radiator?

edit to add a smiley.

jssailem · Dec 24, 2018

@Ron20324 If you could find a way to locate a radiator, how would you get enough air to blow across it to cool the fluid running through it. Then where would you direct all that hot air?

DayDreamer41 · Dec 24, 2018

You could always go with water cooled, but wait, isn't that how it is now?

Will Gilmore · Dec 24, 2018

jssailem said:
Then where would you direct all that hot air?

To the sails, of course.

-Will (Dragonfly)

Ron20324 · Dec 24, 2018

jssailem said:
@Ron20324 If you could find a way to locate a radiator, how would you get enough air to blow across it to cool the fluid running through it. Then where would you direct all that hot air?

I was stirring the pot, JS. BUT, hydronic (car)-type) heaters use a radiator in effect.

Hayden Watson · Dec 24, 2018

In order to do what you want, you could not carry enough fresh water to cool the antifreeze with an open system where the fresh cooling water was discharged. If you want a closes cooling system then you would need an water to air radiator like in your car and it would need significant air-flow to work. In that case you would just run the antifreeze through the radiator and eliminate the heat exchanger.

jssailem · Dec 24, 2018

@Hayden Watson wirh your engineering skills you could design a model system.

@rpell1@msn.com could build the 1st unit. And the sell it on SBO.

Making millions. A Christmas miracle.

jssailem · Dec 24, 2018

30 years younger to begin drinking?
So confused.

Tom J · Dec 24, 2018

rpell1@msn.com said:
Hi,
It's not so much about what's not working as it is about completely eliminating salt water from the equation. The salt water first hits the raw water pump that will seep at some point, allowing salt water to drip in engine parts. Next it hits the exchange promoting corrosion. Next to the riser where there's more corrosion. Finally through the muffler, rotting out the drain plug. Although the level of corrosion is moderate, it would be nice to reduce it to a minimum.as I said, I am just brainstorming for ideas.
Merry Christmas...

You could eliminate the salt water part of your cooling system by extending the fresh water cooling system to a heat exchanger mounted on the keel (some call it a keel cooler). I've never heard of one on a recreational boat, but they are common on commercial craft.

Hayden Watson · Dec 24, 2018

If you eliminate the open part of the system be it fresh or raw water, you will need to completely change the exhaust system as well because the cooling water outflow also cools the exhaust so that rubber hose can be used from the muffler on.

Ward H · Dec 24, 2018

Merry Christmas @rpell1@msn.com ! Maybe a fresh water flush at the end of day, much like flushing an OB, to eliminate salt water sitting in the system. I imagine that would reduce the potential for salt water corrosion.
Before shutting down the engine turn a valve to switch the intake water from salt to your fresh water tank. Run 6 gallons to flush out the salt. Not much different than washing the salt off your boat with a hose as the end of a sail.