Raw water cooling vs. fresh...basics, please

[prv]

How impractical would it be to have a sort of tubing coil, like the steel hoops that keep fishing nets open, which you could drop over the stern when motoring, and through which fresh-water coolant could be pumped to keep an on-board coolant reservoir, cool?

Well, you could, but it sounds like the exact same thing as keel-cooling apart from some added inconvenience and drag

Isn't it often the case that the sea in winter/spring is warmer than the air? Wouldn't it be worth having a small manifold of coolant-cooling pipes on deck, where the heat would encounter a greater temperature contrast?

No, because the specific heat capacity of water is way more than air.

Pete

 

[prv]

I am sure if clever engineer types thought about it they could come up with a freshwater/air cooled arrangement but it's easier (and cheaper probably) to just suck in some sea water and spit out out again.. One the manufacturers warranty is up the damage cause by the sea water is the owners problem..

But seawater going through a bronze heat-exchanger (or a purpose-built cast-iron block with anodes) doesn't cause damage! You're trying to solve a problem that doesn't exist

Pete

 

[wipe_out]

But seawater going through a bronze heat-exchanger (or a purpose-built cast-iron block with anodes) doesn't cause damage! You're trying to solve a problem that doesn't exist

Pete

Maybe but the amount of money and effort people put in to clear the build up in heat exchangers, replace the raw water impellers, replacing anodes or replacing "bits" that have corroded or blocked because of the sea water says there must be a better way.. Remove the corrosive element of the system and in theory you have a more reliable and cheaper to maintain system.. Maybe I am wrong but I think the theory is good..