For a while we used the broken 'fridge as a coolstore - the insulation still worked - but the Boat Safety Scheme examiner wouldn't allow a non-functioning gas 'fridge to remain in situ. It was either repair or replace!
Fortuitously, the owners of a house in our road were having a clear out and Hilary salvaged from their skip some good-quality wood and some insulation material from which she made a cool box that fitted exactly into the space left by the 'fridge.
She painted it, and added some decoration. It may not pass muster on a traditional working boat but I think for someone with no knowledge or experience of boat decoration - and only a passing interest in the subject - its not at all bad. Certainly better than a broken-down 'fridge anyway.
If we are just away for a weekend's boating we bring some frozen plastic water containers that keep it cool and for longer periods we supplement it with a small 12v "beer fridge" decorated in the Eng-er-land football colours that was going cheap just after they'd been knocked out of some international competition or other.