Need suggestions on split freezer/fridge

[Ryban]

Currently conducting an experiment to try and measure the efficiency of the box. I placed 2 10lb bags of ice in there earlier this week, along with a temperature data logger both inside the fridge, and outside the box. This sensor data and some modeling should give me enough info to make an assessment about whether it should be re-built or not.

When I checked on it 2 days later the ice was still probably 75-80% solid, with the average cabin temperature being about 68F during that period. I'll be checking again tomorrow which will mark day 5.

Nonetheless, I'm very impressed so much of the ice stayed solid in that period of time.

I've also concluded that the previous owner at some point had a compressor unit installed as there's a small hole drilled through the liner and foam for the plumping, and what look like mounting holes where the evaporator plate went. I'm guessing at some point it stopped working and he tore it out to use as an ice box instead, given he was no longer cruising and instead just making weekend trips (decades ago).

[Bowdrie]

For that testing you pre-chill the box with your ice, (place the ice in a plastic tub that's raised up off the bottom of the box a few inches on a couple pieces of wood and raise the ice up in the tub on some wood, so it doesn't sit in its own melt water).
After 24 hours remove the ice to discard, dump out the melt water and put in some new ice of an accurate known weight.
Now let the new ice sit in the box for 24 hours.
Then weigh the remaining ice.
Each pound of ice when changing from 32-degree ice to 32-degree water will absorb 144 BTUs of heat.
The resultant answer in BTUs will be the heat ingress into the box over a 24 hour period.
That's how many BTUs your refrigeration system will need to remove each day just to cover the ingress of heat.
Any product from reefer and freezer loads plus heat added from opening/closing will be over and above that figure.
Generally speaking, a reefer will need at least twice that number of BTUs removed, and a freezer at least three times.
If you want hard ice cream the freezer needs ~four times that amount of heat removed
This will be especially shown when the ambient temp goes from your test at 68 degrees to 85>90-degree weather.

[gordonhinds]

Having spent way too much money fixing things the previous owner vandalised I can say - 1) rip it out and start fresh 2) consider a 12v camping fridge/freezer unit. If you want to start long term cruising the chances are that the stuff you have installed or inherited will be super dodgy. So rip out as much as you can including wiring and start fresh. You probably have what will turn out to be rubbish systems (everywhere by the way)

[Kropdad]

I had a similar set up on my boat when I bought her. I ended up just removing the whole set up and rebuilt the woodwork around a portable fridge freezer 90lt twin cabinet. I then added two 115amp gel batteries under the companion way connected to twin 150 watt solar panels and mppt controller. This was 5 years ago and has been trouble free. At the time it was going to cost 500 Aussie pesos just to get a fridgy to come have a look and quote on going forward. The advantage for me is when the fridge does eventually die and can just swap it out for around $1000.