One that I see all too often and even in places (BBC, The Daily Telegraph, etc.) that should know better: the use of the word battleship to describe just about any naval vessel larger than a patrol boat. A battleship is, or really was, a specific type of large warship with heavy guns and lots of armour. One might understand them confusing battleships and battlecruisers (the navy effectively did that at Jutland), but not with frigates and minesweepers.
For that matter, there is the frequent misuse of ship and boat. A ship is a large vessel, while a boat is much smaller: a ship can carry a boat, but not vice-versa. Glen Sannox is a ship…add your own comment to that.