Heat Exchanger VS Radiator

With all the problems with marine engine cooling systems due to salt water corrosion and such, why can't a system be designed similar to an auto's cooling system using a radiator and fan? Surely there's a logical reason such as size constraints maybe.

They make them.

Made an air-cooled installation once!
In a small fishing/research vessel to be used up at Spetsbergen.
Used a Hatz silent pack (diesel), removed the generator and attached a gearbox.
Problem was not to get cooling in but out!

Liquids (aka; sea, lake, river water) are much more efficient at removing heat than gasses (air).
A heat exchanger in physical size is much smaller than a conventional radiator of the same designed cooling capacity.

Taking a lead from haffiman37, you'd also have a huge amount of heated air to remove from an engine bay if a conventional type radiator were to be used. Not to mention a massive supply of air!
Any enclosed marine engine requires the combustion air to be as cool as we can offer it.

So right there is an additional issue with using gas (air) to displace the heat, over that of liquid!
Even in the warmer waters of Florida, for example, the heat exchanger will be much more efficient.

Sea water pump maintenance and trouble-shooting, are just something we must do routinely.

Keel cooling is done to get rid of the heat exchanger. It can be done to get rid of all raw water pumping, but then you have a hot exhaust you must route/insulate. Except for zincs and FW flushing after use, i've not had to do any HE maintenance for 12 years. 24/7 in the salt.

Keel cooling may be an alternative on a displacement boat, but a planning one???

That makes sense, Rick. It seems a ducting system could be designed, but then I guess that would present other maintenance problems. It would be nice if a FWC system could be developed to last more than 4/5 years like the keel cooler that Dave mentioned.

Right now I am troubleshooting my port 454 Crusader's cooling system. The temp gauge is starting to creep up around 180 -190 when at cruise rpm while the stbd engine stays at 160. While at idle the the risers on the hot engine are both at around 150 while the other two on the cool engine are at 110. Yesterday I checked the raw water pump and impeller which were both fine. I'm going back out there to check for air leaks especially around the strainer, maybe buy a overhaul kit for it. I've had the boat for two years and I don't know when the last time the risers and elbows were changed.

Ya gots ta be vigilant with regard to changing the H/E pencil anodes.... and make sure that you are using the correct anode material.

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