Mars-class ship of the line
The Mars-class ships of the line were a class of two 74-gun third rates of the large class ships of the line, designed for the Royal Navy by Sir John Henslow.
The two ships of the Mars class were the first large 74s since the of 1759, carrying the heavier armament of 24 pdrs on their upper decks, as opposed to the 18 pdrs of the middling and common classes.