The Royal). Of ships Royal Navy ships in commission are prefixed since 1789 with His Majesty's Ship (or "Her Majesty's Ship", when the monarch is a queen), abbreviated to "HMS"; for example, . Submarines are styled HM Submarine, also abbreviated "HMS". Names are allocated to ships and submarines by a naming committee within the MOD and given by class, with the names of ships within a class often being thematic (for example, the Type 23s are named after British dukes) or traditional (for example, the s all carry the names of famous historic ships). Names are frequently re-used, offering a new ship the rich heritage, battle honours and traditions of her predecessors. Often, a particular vessel class will be named after the first ship of that type to be built. As well as a name, each ship and submarine of the Royal Navy and the Royal Fleet Auxiliary is given a pennant number which in part denotes its role. For example, the destroyer displays the pennant number 'D32'. Ranks, rates and insignia The Royal Navy ranks, rates and insignia form part of the uniform of the Royal Navy. The Royal Navy uniform is the pattern on which many of the uniforms of the other national navies of the world are based (e.g. Ranks and insignia of NATO navies officers, Uniforms of the United States Navy, Uniforms of the Royal Canadian Navy, French Naval Uniforms). 1 Rank in abeyance – routine appointments no longer made to this rank, though honorary awards of this rank are occasionally made to senior members of the Royal family and prominent former First Sea Lords. Customs and traditions Traditions The Royal Navy has several formal customs and traditions including the use of ensigns and ships badges. Royal Navy ships have several ensigns used when under way and when in port. Commissioned ships and submarines wear the White Ensign at the stern whilst alongside during daylight hours and at the main-mast whilst under way. When alongside, the Union Jack is flown from the jackstaff at the bow, and can only be flown under way either to signal a court-martial is in progress or to indicate the presence of an admiral of the fleet on-board (including the Lord High Admiral or the monarch). The Fleet Review is an irregular tradition of assembling the fleet before the monarch. The first review on record was held in 1400, and the