Should I switch my fridge off on the ferry?

Swifty 123

We are off to France next week, Yippee!  Question is, we are on the Dover Calais ferry which is just over an hour, would you normally switch the fridge to the off position to prevent flattening the car's battery or would that sort of duration be Ok? Never
been in that situation before as we have always been travelling when hooked up.