When we were discussing names for our child I suggested Tyrone, under the theory that if he got in a fight at school, and the other kid went home and told his parents he got in a fight with Tyrone, they'd think he was some tough brother from the 'hood and tell their child to just "leave Tyrone alone". When my daughter was born, my wife absolutely vetoed 'Tyrona'.
S/V is Sailing Vessel
USS is United States Ship... this is what you would use if you were a Navy Ship.
HMS is Her Majesty's Ship
Most freighters are M/V, Motor Vessel... and there are a lot of stinkpots out there that are M/V also.
And the classic S/S means Steam Ship.