It all depends on the ambient temperatures and the efficiency of your fridge's insulation as there will be no refrigeration taking place for the whole of the lengthy crossing.

We keep all our cold stuff in the domestic fridge/freezer until just before departure so it is as cold as possible when we set off from home.

Have you thought of freezing a couple of those blocks that tent campers use and putting them in the bottom of the fridge?

When the fridge in our old VW camper went tits up, the first we knew about it was when we opened the door and the butter ran out and pooled on the van floor.

Unless you can run the fridge on gas, which I doubt will be allowed to, then you cannot leave anything perishable in the caravan fridge for that period of time. I'm also unaware of hook up options onboard although an advance call may be worthwhile as the ship must be carrying refrigerated lorries.
We carry a table top freezer in the boot and that drops from -21 to -9 when unplugged over an 18.+ hour period. The caravan fridge does not have the same level of insulation so even assuming a 5c start then you don't really have a hope.

Colin

The freezer pack idea that Brian mentions will help but our advice is to not load too much in the fridge and stock up when you get there. It's cheaper anyway :-) There's a number of supermarkets in Laredo if that's where you intend staying and they have large car parks that'll fit the car and the Eriba.
Randa

Jaca's lovely. Try and do a tour of the Fort.
Randa

I think we sailed on that one. As soon as it left port (left port:that was clever) many of the cars on the upper open deck had their alarms go off.

Are you on the starboard oars or the port ones?
:-)
Randa

If you are on the open deck does that mean you can run the fridge on gas?

Colin

Yes, the little yellow light. We use it all the time but can't tell if it works or not

Randa