external radiator for cooling system

[mattoc]

I have a LD 20 diesel and am researching alternative cooling systems rather than the common keel (copper piping running along the side of the keel) and raw water (in through the hull skin into engine and out muffler) systems.

Why not mount the radiator to the external transom wall under the waterline surely this would provide adequate cooling to the motor, being that water temperature is always greatly cooler than air temperature (which the motor was designed for) and there is always a constant flow of cold water.

Wouldn’t this be very similar to a heat exchanger were raw water is brought up through the hull skin and circulates around the internals of the heat exchanger and out through the muffler.

ANY help would be Great help
Thanks Matt