Camping World, an RV supply place, sells a little D-cell powered fan 
(Fridge Mate Fan) for around 15 dollars. They have locations throughout 
the USA, call 1-800-626-5944 for a location or ordering info.  I've 
never ordered from them, so can't attest as to their customer service 
quality. I imagine Boat/USA might also have such an animal. 
Scott
'84 westy