Watching paint dry!
Forward, Back, Left, Right and front thingy moving left and right (obviously I have no clue about nautical terms) is all you can do; well, and Alt + F4.
Unfortunately, there are only a few maps to sail around in; but it is filled with AI traffic and plenty of surroundings. The speedboat is fun but quickly gets repetitive after a few minutes. Thankfully the patch fixed most of the problems many users were having, like other AI ships ramming into you and full speed.
You do have the ability to create a scenario of your own, and there are quite a few missions which are un-lockable as you progress through the game. There is a tolerance of how much damage you can do (in $) in a mission, but one mistake and you pretty much have to do the whole mission again!
Sometimes playing Ship Simulator is like watching paint dry. It has its moments of brilliance like... like... um... being able to walk around the upper deck of the titanic, or... zzzzzzzz (falls asleep).
In summation, Ship Simulator has plenty of room for improvement. I'd like to see more areas to cruise around, more controls of you boat/ship and better scenarios (Severe weather, big waves etc.)
As it stands, I will leave the box on my shelf to start collecting dust!