ROYAL NAVY PENDANT NUMBER SYSTEM
 

 
WORLD WAR II    1939-45
 

Notes
 

Flags have long been used for signaling at sea, and Britain's Royal Navy was a pioneer in the development of such visual signal techniques. The ancestor of today's RN signal flag system was introduced around 1800. Over the years it was progressively developed and improved, and until the advent of radio, it remained the primary method of communication between ships at sea. The system in use by the RN by the late nineteenth century proved definitive, served with only minor revisions in both world wars and remains in use today. Like the current International Code, the RN system is based on a set of flags and pendants (pronounced pennants), each of which denotes a letter, a number or a special meaning. By hoisting these flags in specified combinations, signals can quickly be passed from ship to ship.

Signal flags are also used to show a ship's identity, but since spelling a name like Prince of Wales would require a complex flag hoist, a numeric or alphanumeric code is used instead. British warships have been assigned numbers since the eighteenth century, enabling them to identify themselves by "making their number" via a signal flag hoist.  As warships became more specialized and different classes proliferated, the RN elaborated its numbering system by allocating "flags superior": a letter preceding the ship's number, so called because it was hoisted above the number pendants. The flag superior is either rectangular, swallow-tailed (a burgee) or triangular, while the number pendants are long and tapered. For repeated numbers a substitute pendant is used (see the illustration below for H22, HMS Diamond). During World War II the flag superior was assigned arbitrarily and did not indicate the ship type. After the war, however, the RN rationalized its pendant number system so that the flag superior indicated the ship type, e.g. D for destroyers, F for frigates, etc.

The illustrations below show all the alphabetical flags and numbered pendants required to make up a pendant number hoist. Not all flags and pendants of the RN system are shown, however. The full set included numerical flags (as opposed to pendants), along with a number of special flags and pendants such as the Affirmative and Negative flags.

The pendant number hoists depicted below are based on the allocation of flags superior after the changes made in mid-1940. Capital ships (battleships, battlecruisers, aircraft carriers) and the newer classes of cruisers began the war with two-digit pendant numbers (no flag superior) and no changes were made subsequently. These ships hoisted their pendant number under a generic distinguishing flag. Older cruisers such as the "C" class were allocated flag superior D. Older destroyers had flag superior G, H or I, while flag superior R was allocated to the War Emergency classes of destroyers laid down after the commencement of hostilities. Flag superior U was allocated to escort sloops. Other escorts (frigates and corvettes) were allocated flag superior K. Due to the large numbers constructed, many of these ships had three-digit pendant numbers as shown below. Mine warfare ships were allocated flag superior Ma rare instance in which the flag superior indicated the type of vessel. Submarines were given pendant numbers with a flag inferior, e.g. two or three numerals followed by a letter. In practice, however, submarines rarely if ever flew their pendant numbers. There were a few other flags superior specified for minor warships and auxiliary vessels. In cases where the flag superior was changed, the numbers usually remained the same, e.g. from D22 to H22. Capital ships and cruisers did not usually have their pendant number painted on the hull, but destroyers and other ships usually did. The Commonwealth (Australia, Canada, New Zealand) navies were included in the RN's pendant number system.
 



 

A wartime photograph, circa 1944, of the Royal Navy destroyer HMS Wakeful (R59) flying her pendant number

 

ALPHABETICAL FLAGS

 

A

 

B

 

C

 

D

 

E

 

F

 

G

 

H

 

I

 

J

 

K

 

L

 

M

 

N

 

O

 

P

 

Q

 

R

 

S

 

T

 

U

 

V

 

W

 

X

   

Y

 

Z

 
 

DISTINGUISHING FLAGS

 

Battleships

 

Aircraft Carriers

 

Cruisers

 

NUMERICAL PENDANTS

 

1

 

2

 

3


4


5


6


7


8


9


 

0

 

SUBSTITUTE PENDANTS

 

First Substitute

 

Second Substitute

 

SOME PENDANT NUMBER HOISTS

 

41    HMS King George V
"KGV" Class Battleship

 

50   HMS Courageous
"Glorious" Class Aircraft Carrier

 

39    HMS Devonshire
"County" Class Heavy Cruiser

 

D87    HMS Cairo
"C" Class Antiaircraft Cruiser

 

G03    HMS Cossack
"Tribal" Class Destroyer

 

H22    HMS Diamond
"D" Class Destroyer

 

I42    HMS Windsor
"V & W" Class Destroyer

 

U57    HMS Black Swan
"Black Swan" Class Sloop

 

 

K253    HMS Helmsdale
"River" Class Frigate

 

 

K186    HMS Anchusa
"Flower" Class Corvette

 

 

M84    HMS Welshman
"Abdiel" Class Fast Minelayer

 



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