Oh bugger me, that's a lot of ships. How many of them are present in Kancolle?
As of July 24, 2015, there are 153 ships currently in Kancolle (not counting remodels). The upcoming Summer 2015 Event is looking to add perhaps 2-3 more ships to the roster.
By the way, the ship where the commander holds command is called the flagshipFleet, Carrier Fleet, Area Fleet, Combined Fleet18th Battle Division
(Cruiser Division 18)16th Destroyer Division
(at the break of the war, Kuroshio is moved to 15th division)2nd Torpedo Division
(Destroyer Squadron 2)Combined FleetAt the break of the war, consisted of Jintsuu and the 8th, 15th, 16th and 18th Destroyer DivisionCommander1st Carrier DivisionGroup of aircraft carriers and seaplane tenders: Carrier Division (Koukuu Sentai)How the commanding officer of Destroyer, Submarine, and Torpedo squads are calledCommanderCommanderCommanderOh myCommander-in-ChiefGroup of battleship and cruisers: Battleship Division (Sentai)Group of submarines and submarine tenders: Submarine Division (Sensui Sentai)Group of light cruiser and several destroyer division: Torpedo Squad (Suirai Sentai)