Business Dress........ what the!!!!

So tomorrow night I've been invited to a cocktail party on board a French helicopter carrier!  Its to do with an event I'm organising for work, and I'm very excited at the randomness of it!!  However, the invite says business dress, so the conundrum is, what the hell do I wear??  Moving to another country with just 2 suitcases means I don't have my full wardrobe to choose from, and seeing as about 40% of my clothes are beachwear, I'm stressing!! I'm hoping a dress and blazer will be OK............ well it'll have to be, its all I have.  Whats the worst they can do, throw me off the boat ...................?!?!?

Will post some pics tomorrow when I've decided what the hell to wear!!