What exactly is your question admiral thomas?
If you mean that, how come HMS King George V is on Flight Simulator X, but Not Ship Simulator, thats generally because we don't really have War ships (I'm assuming you mean the WW2 Battleship, yes?) in the game. Also, as Llamalord said, different games can have different styles, so Flight Simulator X probably dosen't have any of our ships/styles, and visa versa.
Hope that clears things up for you!
Jack