I ended up finding a local boat supply store (IWW) that sells the factory replacement Waeco (sp?) fans...12v 150ma, so used 3 of those...one replaced my dead factory fan, another positioned to cool compressor, and a third pointed upward to assist the hot air to rise to the vent at top of cabinet.
Made a tracking chart, and it looks like I am now able to lower fridge thermostat from 6 to 4 (7 being highest), while still having the fridge thermometer in the "sweet" range, and freezer now freezes ice cubes over night (never did that before).
The 3 fans each draw just 150 ma, so pleased that my 250w solar panel easily keeps up when anchored out or on the mooring. Pretty "cool" for a 18 year old NovaKool fridge. Now the Heineken's are really cold here in the tropics...