Petty cash aboard uboats.
 

Would German (or any other) uboats carry petty cash for unexpected expenses?

For example putting into a port unexpectedly, paying for fresh food, repairs, slappers etc?

I would imagine that the crew had some money...but repairs and food I would imagine are supplied by the port. They are in the Navy you know. They Navy would repair their boat and supply them with food. Anything else (Wink wink) the Germans probably got because they were in the Navy and chicks dig Naval Uniforms. :har:

They likely did have some money or perhaps gold more likely or some sort of "IOU" so that they could pay for fuel at a neutral port of course thing is it is a sub and very valuable to any enemy so exposing the sub in anyway was risk so they likely would destroy the sub if a serious issue came up with no recourse rather than take it to a neutral port where an enemy element might also be and take the chance to sabotage there where very few neutral ports anyway.

I know for a fact that the British did perform clandestine asks of sabotage on German surface vessels in neutral ports so a sub would just be asking for it and the neutral port might decide that the reward for handing over a U-boat was worth more than what they would get for selling some diesel.

I would say yes they would have some cash on them, after all when they where in port there was all those knocking shops and bars to visit :D

There are records of U-boats and a few portuguese cod fish fishing sailing ships exchanging food, mainly cod for canned food (meat and other stuff), since the sailors normally ate several parts of cod during the main part of the trip.