The small front opening type fridges use a bit more
power than a thickly insulated
boat fridge. A quick
google search suggests your model is a 3 way fridge (running on gas as well) these use a different
cooling mechanism and use a lot more
power on 12v.
Bottom line is your
consumption is what I would expect even in a cool climate with that type of fridge.
A common solution is to keep the fridge off and use it as a pantry and emergancy back up it can be turned on when on
shore power or running the
engine.
Another thickly insulated fridge is then installed elsewhere.