Frozen fridge coolant lines

The precious owner has already added some insulation but the majority of the line is difficult to reach. 

Has anybody had success in insulating these lines post delivery?

Maybe a sailor or two needs a brush-up on Physics 101. That is where you learned about condensation, dewpoint and hygrometers.

When you isolate a cold coppertube, you are preventing a process where the hotter air around the tube gets cooled down, thereby reaching the dewpoint where the humidity in the cooling air condensates on the coppertube, where it instantly freezes into ice.

In plain english, cold air contains no or little water, while hot air can contain a lot more.

So if you notice, that Captain Cook has isolated both the hot and the cold coppertube, he may have made an error. The hot tube could as well have been left alone, and release its heat to the colder surrounding air. This would presumably release the workload of the ventilator, which is trying to blow the hot air away from the evaporator on the compressor.

If one experience a lot of ice on the copper tube, it will be wise to check if the humidity of the air around the compressor is excessive.

I have been a member here for 16 years, and I have never seen an ice build-up like yours before.

It seems that your 371 fridge is working better than the unit in the newer H370/H400 models.

There are hundreds of posts on myhanse about the poor Isotherm unit and Danfoss compressor.

In my boat I had the R134 coolant topped up, and my fridge just now hold 4-5 degrees Celsius when the outside temperature is 30, and the ice-box works fine.

To me it seems that there might be more humidity in your boat than in mine. I have never seen ice on the tube, and the insulation of the copper tubes was to try to make the fridge temperature lower.

If excessive humidity is the problem, you can try a dehumidifier, they are available both in large electrical versions, and as smaller inexpensive units like in the picture.

Maybe you should check the fan on the compressor. If the fan is not working, it could be the reason for the build-up of ice on the tube. Also read this link:

https://mspplumbingheatingair.com/blog/why-is-ice-on-my-outside-air-conditioner-pipe

If your ventilator on the compressor is working okay, it is possible that you need to top up the R134a (use the Advanced search: >any date>all forums>"R134a" and get advice.

Your compressor is a later addition to your boat. The bayonet-couplings are a rather new invention, made for the DIY people. When amateurs connect these tubes, there is a risk, that some cooling fluid can escape. Also it is common that the couplings are not tight enough. There is advice about this on the homepages of Isotherm and others.