isotherm icebox conversion

Fettlin’ Day! October 29, 2023

colin bastable Leave a comment
Colin aboard Frank.

Frank used to have a 12volt fridge, which also ran off mains when alongside.

I mentioned (https://wordpress.com/post/frank-justfrank.com/306 October 2015) the fridge, which I extracted from its hole by the engine : “Most useless kit: the refrigerator. I donated this to a charity in Dartmouth. Every time I had a problem with the electrics or engine I had to haul it out of its home.”

So ever since I have had this hole, having converted the icebox to be a fridge:

The gaping hole where the fridge lived.

I am going to finally turn it into a storage cupboard. I’ll leave access to the engine water inlet. There is a separate access door under this pic.

Ice-Box Conversion to Fridge

colin bastable 3 Comments

Last year, I posted a blog about my plans to install an Isotherm Self Pumping refrigerator conversion – and this year I have finally completed the job. It works!

The ice-box, now refrigerated, is to the left of the cooker, and the compressor gubbins is to the right, in what was the trash container (that I used as a dry food store). I fitted the compressor to the bottom half of the compartment, and put a clear Lexan cover over it, to protect the unit from spilled water from the taps. I will fit a drain, to take spilled water down under the sink.

The evaporator is fitter to the ice box, which had no insulation on the engine-side, where the fridge used to be. So I fitted some closed-cell insulating foam board – the purple stuff, an offcut of which I have used to act as extra insulation for the lid. I will seal this piece to make it more durable.

Now, I need to seal the windows, to stop rain and seawater from leaking in and draining into the icebox. The great news is that a couple of cooler blocks and some bags of ice in the bottom of the icebox stay frozen, and there is no compressor noise, nor is there any pump to consume battery power whilst under sail.

Isotherm water-cooled refrigerator upgrade to coolbox 

colin bastable 1 Comment

A rather inelegant title for a cool technology addition to Frank.

Isotherm have a range of freezer/fridge solutions that can turn a coolbox into a freezer or fridge. The SP (Self Pumping) range appeals to me because there is no need for a pump, thus reducing power consumption at sea.
The system works by replacing the existing, through-hull sink drain cock with a larger (2.5″) unit inside which is embedded a coolant coil. The under-water exterior surface of this unit uses sea water to cool the refrigerant via the coil, which is wrapped around the drain out-pipe. 

This picture is worth a thousand words:


The unit I will install is the SP 2051 with an “o”-shaped cooling panel:


The drainpipe cock is attached to the assembly.

The under-water face of the self pumping cock. An anode fits to the face.


The sacrificial anode was not in the box – I shall get one, make sure I have all the components and then have the assembly fitted when Frank is hauled for her annual scrub and antifoul at Ingleside.

I can install the compressor later, or maybe have the yard do it.