One very obvious thing is missing from my picture [which is a java script, so if you can't see it, enable your java reading tools] and that is a PENNANT NUMBER. After all, don't all warships have them for recognition and use as a visual callsign, and are they as obvious as one might think, or have thought? For the record, but as you will see, all vessels, including battleships had them, but not all classes of ships displayed them overtly.


For many years now, and still in vogue today, we have used a set of letters which in the main, have been the first letter of the type of ship to be recognised. For example the letters A, D, F, H, S, M and P are synonymous with Auxiliaries, Destroyers, Frigates, Hydrographic ships, Submarines, Mine Warfare Vessels [Sweepers and Hunters but not necessarily Layers - Manxman, Apollo and Ariadne were the BMW's of the 1940-1960, the fastest ships in the navy bar none, but they had the letter 'N' as a pennant], and Patrol Vessels [note not 'BOATS' - they are submarines] respectively.  Other pennant numbers [letters] which do not follow the logicality mentioned above, are the letters 'R' and 'L' where R = Aircraft Carriers {as near as damn it, five out of the sixteen letter are the letter 'R' = top side of a quarter in favour of !!!}: and 'L' meaning Landing Craft or plain and simple Let-'em-have-it [for these ships are top-loaded with testosterone crammed full of combat troops raring to go] and are currently named, the 'OCEAN' our largest warship, the 'ALBION' and the 'BULWARK'. This class of ship, for they are AMPHIBIOUS WARFARE experts, would have preferred the letter 'A' but that was pinched by the boring old Auxiliaries  mentioned above.  We have just one ship in the R.N., with an 'A' Pennant letters [the Endurance] but many ships in the Royal Fleet Auxiliary whose task is to support the Fleet with food, water, fuel, ammunition and stores.  We also have RFA ships with the letter 'L', again, as in the case of R.N., ships, meaning landing craft/amphibious ships. For the purposes of  this page, the official list of vessels over which the Admiralty has OPERATIONAL CONTROL {2005/2006}  but not counting things like PAS Vessels or Hovercraft etc, is:-

3 Aircraft Carriers 9 Destroyers 18 Frigates 15 Submarines 3 Assault Ships 20 Minehunters 24 Patrol Craft 6 Survey Vessels 22 RFA's

and although a meaningless exercise, in unit terms, the total is 120 vessels. For many years of the post WW2 period, all these units had their Pennant Numbers painted on the ships sides [and sometimes on the stern] or on the conning tower, but for reasons of stealth during the 'cold war', submarines alone ceased the practice of showing Pennant Numbers. The modus operandi of a submarine, except when in harbour or on surface passage, was such that it rarely showed itself and when it did it was better that its 'name' was not known, although of course its 'class' could be readily ascertained. This anonymity didn't matter for surface vessels who were always visible and always in the eye of Russian AGI's [Auxiliaries [innocuous trawlers and the like until one studied them more closely to see them bristling with listening devices] Gathering Intelligence] who were ALWAYS in company with British/NATO ships when exercising. In addition to Pennant Numbers, many frigates and above carried helicopters and their flight decks were clearly marked with letters associated with the ships name.

The 'thought' part of the question above is not as easy, in fact it is often


To answer the question I have to take you back to the latter stages of  WW2 to just before the Normandy Landings in 1944. At this time, the Admiralty had OPERATIONAL CONTROL [for most of the time, full control] of a vast armada of war vessels.  This phalanx of ships comprised of the RN, RAN, RNZN, RCN, RIN {Indian}, SANF {South African Naval Forces}, Free French Navy, Yugoslavian Navy, RNethN {Netherlands}, RHN {Greece}, RNN {Norway}, Polish Navy, and units of the Italian Navy after the overthrow of Mussolini. The mind boggles when looking at the following statistics of what this operational control meant, which are:-

16 Battleships
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1 Battlecruiser
72 Aircraft Carriers
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77 Cruisers
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275 Destroyers
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231 Submarines 1504 Minor Combatants
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506 Naval Auxiliaries
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n/a District Craft [too many to count]
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n/a Landing Craft [too many to count]

I have two reactions at this point, one being how does ANY organisation cope with that lot {?}, and the second, little wonder that the Axis Forces capitulated {!}, not forgetting that these numbers are probably equalled if not surpassed by the U.S. Naval Forces brought to bear. Where necessary, to help you unravel the types of ships/column headers above, I have added little cameo's inside each block for you to read.

Moving on then, and remembering that the central theme is PENNANT NUMBERS/VISUAL CALLSIGNS, surrounded by lots of other criteria which were used to IDENTIFY any particular ship. Throughout my web site I have talked much about SHIPS NAMES, and SHIPS INTERNATIONAL RADIO CALLSIGNS, two very obvious ways of identifying a ship/vessel. Now, I intend to talk about CLASSES of ships, TYPES of ships, SILHOUETTES of ships, PENNANT NUMBERS of vessels and how there were assigned, and type BLOCK NUMBERS.  To do this, I have created several PDF Files each dedicated to its own subject of IDENTITY.

I start with BLOCK NUMBERS, where each class of ship was assigned a specific number in a block.  Here you will be at home for you will see immediate sense and liken it to present day Pennant Numbers - but don't get too excited, the likeness will not last.  Open this file as an introduction to the subject - you may also find it useful later to check what a-so-and-so type of ship is BRIT & COMM SHIPS WW2 - TYPES.pdf.  Continuing in the BLOCK system, Battleships have 'BB' Letters and are Numbered '01', '02' etc; Battlecruisers have 'CC' [why, I don't know] and Repulse is shown as '02' - the mighty Hood was 'CC 01'. These files need little introduction. 

 Here then is the BLOCK PDF ****Battleships, Carriers, Cruisers, Fleet Destroyers & Subs by  Basic Number.pdf, **** Once opened scroll to cruisers and note that the USN authorities have called the group having the Newfoundland, the Uganda and the Ceylon, the UGANDA CLASS when it should have been as per RN instructions the CEYLON CLASS  - followed by BRITISH MINOR COMBATANTS WW2.pdf and the BRIT  AUX Local Vessels  Landing Craft.pdf for all other vessels.

Now the confusing part.  In the following PDF Files [2 in number] you will see strange things like page 2 for example, Searcher, which is an aircraft carrier, is D40: page 3 F24 is the Tyne a destroyer tender or depot ship, and on page 4, 'NEW' fleet destroyers have 'G' Pennant letters.  This is because FLAG's - yes good old fashioned BUNTING, were used to denote types/classes of ships instead of the system we use today, where a Destroyer is D something-or-other. Then, by flags, the FLAG assigned to the class/group of ship would be hoisted first [superior] followed by the two or three figure assignment e.g. K399 for the corvette HMS Tintagel Castle [post war to become F399]. This was also the callsign used by signalmen exchanging signals by flashing light.  Note that British battleships, aircraft carriers and cruisers did not have a distinguishing flag, just two figures 00 through to 99. Note also that only destroyers, submarines and combatant ships smaller in size showed their pennant number on their vessel.  Thus my little java animation at the beginning of the page is shown correctly. The two files cover the whole range of pennant numbers associated with the British [Commonwealth and other navies who fought with us] PENNANT NUMBER INDEX - 00 to K549.pdf and PENNANT NUMBER INDEX - K550 to Y92.pdf.

What follows next is a PDF File showing all the vessel who fought on the British side under whose control and guidance, training and support they operated COMM & OTHER NAVIES ON ALLIES SIDE.pdf.

Some silhouettes now and all of them of British ships, either built by, operated by, or loaned to other navies by SILHOUETTES OF BRITISH SHIPS WW2.pdf.

Well now you have a great deal of data and we can put this together in a comprehensive list which you will find here, again in PDF File, but three of them to cover the full range of alphabetical names, navies, types, class and pennant number BRIT & COMM SHIPS WW2 Part 1 - A to GL's.pdf, then BRIT & COMM SHIPS WW2 Part 2 GL's to SA's.pdf and finally BRIT & COMM SHIPS WW2 Part 3 SA's - Z.pdf.

In summary we can identify a given vessel in many different ways, and even more if we used the pro-nouns 'her' or 'she'. Take the battleship Nelson for example.  Once seen never forgotten because of the way her guns were mounted, but in our description of her we could also be talking about the Rodney. To be focused and one hundred percent sure and accurate, we use data which is unique, so in this case we could use the

The Name Pennant Number/Visual Callsign Block Number Encrypted daily changing callsign International Radio Callsign
HMS Nelson 28 BB 11 Variable but always unique GMAN {fitting 'cos it could mean Gunman}

Before I say goodbye, you may have seen that this information, or part of it, was published/printed in the USA. Where it does mention ONI, that is the USN's Office of Naval Intelligence. Why?  Well first of all the information came direct from the British Admiralty and on a regular basis so it was  correct, relevant and as up-to-date as possible and the conduit through which it passed was established several time a day. It was published from the early days of the war in Britain, and with great sensitivity too. When a vessel was lost the navy felt it deeply, and simply scrubbing out the name of the vessel from a reference book was bad for morale and accepted as a very short-term-fix only. As soon as possible the reference book was reprinted and issued telling the recipient to destroy by burning the old version. On average it was printed/published monthly such was the rate of change of our fortunes/losses. As the war progressed this became a financial burden and paper was a scarce commodity.  1941, at the end of which the USA entered the war, necessitated many reprints due to our unprecedented losses in terms of ships and men. Eventually the ONI with its access to copious amounts of raw material, its technological expertise and facilities and with a keen sense of sensitivity towards the data being deleted and added, plus the need to centralise information in readiness for a Europe under a U.S Commander-in-Chief [General Eisenhower] eventually took over the task of editing, printing and distributing.  They did an excellent job for which we were grateful.