What is the comparison with the new separate space Fridge and Freezers?
Some of the new units have dual compressors and their power consumption as a result is very high. Generally running a separate space for freezing to the refrigerator space is difficult to do in an energy efficient way. It is far more efficient to have a separate freezer to the refrigerator. This has an added advantage that if during the trip there is not a requirement for freezing (either a poor fishing trip or you ate it all!) then you can rest one of the units until needed later in the trip.