There is sometimes a capital ship moored, usually a cruiser like a Fiji or something, and on rare occasion a plump, juicy battleship, and then also one or two destroyers docked. The odds of one of these capital ships being there decrease the later into the war you are. If you want a spoiler, a schedule of when and what capital ships are moored there can be found in the wiki, at the bottom of the page:
http://www.communitymanuals.com/shii...unting_Grounds
Or for more fun, don't look at that spoiler schedule, and just be surprised at whatever you happen to find there or not, and just be happy when you come out alive!