This is also applicable to the PPM thead

Trawlerguy ...
You may wish to do some research re: sub-zero.
Sub-zero has proven to be less than optimal (maybe the worst)
refrigerator you can own on a boat.
Its hugely inefficient, and many in the Nordhavn crowd are throwing
theirs out ... and de-activating the de-icing circuit has often been
talked and asked about and desirable.
Their reliability has been fair to poor.

In general- any de-icing model is a Very Bad Idea.
Your total consumption is often 4-8 times higher for a model that does
this, than a std refrigerator model !

De-icing actually heats the inside of the refrigerator with a fairly
high current. Inefficient.
You then need to re-cool the surface and contents. Very inefficient.

In my opinion, the best option is the most energy-efficient consumer
model you can find.
Bog std, big box store stuff. Look at consumer reviews, and measure
actual used current if you can locate someone with the same model. Power
companys often give or rent metres to measure used power in an
appliance, maybe a 1$/day or free...
Due to economies of scale, you will probably get a cheaper,more
reliable, more efficient system than any custom solution at 20x the cost.

A compressor in a refrigerator is the cheapest, best way to make that
piece of equipment known to man, due to the nr of millions that are
produced, and the fact that manufacturers are required to give a 2 year
guarantee for and in consumer use. Over 40 years of commercial
competition, manufacturers know how to build them efficiently, and
tooling costs are by now under 1$/unit.
If you want a better way, you need instrument- grade stuff, that is
available from some industrial suppliers, and is very, very expensive.

So-called marine stuff in DC is usually extremely inefficient
(electrically) and unreliable (mechanically), although pretty to look
at, imo.

Inverters are about 90% efficient - your cabling losses in DC systems
are similar !

If you want to make it look nice, a custom cabinetry/stainless
chassis/shelf/cupboard with removable (hinge) pins is the way to go,
imho. It will allow you to change/dismantle/replace it whenever,
wherever, with 5 minutes work.

One very important note;
The hot-air outlets on refrigerators, be they cold/plate or whatever,
are often to almost always not vented or have constricted airflow. The
energy consumption of the system is 3-4 times ! higher on such systems.
Do not think that You are heating the inside (often desirable) - you are
mostly heating the sea  through your hull, and you are unlikely going to
enjoy the results !

Some have put a small 2W (computer fan) 12 V fan on the hot air outlet
and or removed grilles and report 1/3 of the previous power draw due to
not having restricted airflow.
This is, in my experience, a typical design failure very common to all
manufacturers.
Its also, in my somewhat cynical option, due to us, the consumers,
normally not knowing or caring about such issues, nor demanding that
they be properly built in the first place.
When buyers want to know -
Whats the energy use of the top 5 appliances ?
Whats the MTBF of same and cost (in $ and hours) to replace same ?
Manufacturers will happily give us good reliable solutions at a fair
price related to their capacities and manufacturing costs.

"Consumer Reports" agrees with Hannu. Sub Zero has the worst reliability
record based upon their survey data. Also, they sell mostly to home
builders. There are few if any retail dealers to help you. Buying other than
a household appliance on a boat big enough to accommodate them is plain
silly.

Ron Rogers