Pennant number

While the numbers allocated to major warships (except for a few older vessels) would generally remain stable into the 1930s, destroyers were subject to further revisions, stability being reached in January 1922.Accordingly, older cruisers had the flag-superior 'I' added in front of their existing plain numbers; as a result, submarines, which had previously used 'I', were given a new scheme of flags-inferior.between the flag superior or inferior and the number, although this practice has gradually been dropped, and inter-war photos after about 1924 tend not to have the full stop painted on the hull.The Admiralty took the situation in hand and first compiled a "Naval Pendant List" in 1910, with ships grouped under the distinguishing flag of their type.In addition, ships of the 2nd and 3rd (i.e. reserve) fleets had a second flag superior distinguishing from which naval depot they were crewed: "C" for Chatham, "D" for Devonport, "N" for Nore and "P" for Portsmouth.Royal Navy submarines of the "H" and "L", and some transferred American vessels, were not issued names, only numbers.After the Second World War, in 1948, the Royal Navy adopted a rationalised "pennant" number system where the flag superior indicated the basic type of ship as follows.From 1925 the following bands were worn; When single funnelled destroyers entered the fleet with the J class in 1939 and with an expansion in the number of flotillas, the system was changed accordingly.Post-war Flotillas were no longer identified by bands, but by large cast metal numbers bolted to the funnels.The United States and Canada do not participate in this system; their ships are identified by unique hull classification symbols.
Hull classification symbolHull classification symbol (Canada)Royal NavyEuropeCommonwealth of Nationsflotillaburgeetorpedo boatspennanttorpedo boat destroyersprefixsuffixFirst World Warfull stopBritish EmpireChathamDevonportPortsmouthHMS Lancasterdestroyerscapital shipsaircraft carrierscruiserslarge auxiliary combatantsminesweeperscorvettesfrigatesescort destroyerssloopsminelayersriver gunboatsauxiliaryfishing trawlersdrifterGermanU-boatsORP Orzeł (85A)U classRiver classH classL classGrampus classO classP classV classS classT classA classUnited States Navylend-leaseR classOcean (L12)Albion (L14)Royal Fleet AuxiliaryRoyal Maritime Auxiliary ServiceRoyal Navy Auxiliary ServiceHMS LofotenRFA ProteusHMS ChallengerXV Patrick Blackettflotilla leadersMediterranean FleetAtlanticHome FleetJ classG classI classTribal classK class8th Destroyer FlotillaF classV and W classWestern ApproachesRosythE classGibraltarTown classChannelB classC classD classescort carrierscast metalflight deckhull classification numberHMS BulwarkHMS DauntlessHMS Queen ElizabethRFA ArgusRFA Lyme BayCommonwealthhull classification symbolsAlbion classRiver–classDaring–classDuke–classInvincible–classQueen Elizabeth–classBay–classTide classWave–classFort Rosalie–classDe Zeven Provinciën–classHolland–classHNLMS RotterdamHNLMS Johan de WittHNLMS Karel DoormanHalifax–classHarry DeWolf-classSt. Laurent-classAnnapolis-classIroquois-classHMCS ProviderProtecteur-classBraunschweig–classSachsen-class frigateCharles de Gaulle aircraft carrierMistral–classHorizon-class frigateAquitaine–classLa Fayette–classVasco da Gama–classBartolomeu Dias–classAhmad Yani–classMartadinata–classBung Tomo–classFatahillah–class corvetteMakassar–classCakra–classNagapasa–classDiponegoro–classShip prefixList of squadrons and flotillas of the Royal Navy