The Royal Navy is one of the largest navies in the world in terms of gross tonnage (weight and size of all their ships). The Royal Navy and Royal Fleet Auxiliary have 98 ships including aircraft carriers, submarines, minesweepers and patrol vessels as well as the ships of the Royal Fleet Auxiliary. All ships in the Royal Navy are called "Her Majesty's ships" (Or HMS for short), because by constitution the Queen owns them and has command over them. Ships in the Royal Fleet Auxiliary are called "Royal Fleet Auxiliaries" (Or RFA for short) and are also technically owned by the Queen. In times of a male monarch the "Her" is replaced with "His".