Anti-torpedo boat gun of the late 1800s. Some of these were converted to AA guns during World War I. None appear to have survived long enough to serve during World War II.

Gun Characteristics

Designation 12-pdr [3"/50 (7.62 cm)] 18cwt QF Mark I
Ship Class Used On King Edward VII (last three units), Lord Nelson, Dreadnought and Minotaur classes
Monitors: Abercrombie, Lord Clive, Marshal Ney and Erebus classes, plus M15 through M28
Date Of Design N/A
Date In Service N/A
Gun Weight 0.9 tons (1.0 mt)
Gun Length oa 154.7 in (3.929 m)
Bore Length about 150 in (3.810 m)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume N/A
Rate Of Fire 15 rounds per minute


Type Separate
Weight of Complete Round N/A
Projectile Types and Weights HE 2crh: 12.5 lbs. (5.67 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge 2.75 lbs. (1.25 kg) MD
Muzzle Velocity 2,600 fps (792 mps)
Working Pressure N/A
Approximate Barrel Life 1,200 rounds
Ammunition stowage per gun Monitors: 300 rounds
Lord Nelson: 230 rounds
Dreadnought: 300 rounds
Others: N/A


Range with 12.5 lbs. (5.67 kg) HE
Elevation Distance
20 degrees 9,300 yards (8,500 m)

Mount/Turret Data

  • Single Mounting
    • Africa (14), Britannia (14), Hibernia (14), Lord Nelson (24) 1, Dreadnought (28) 2, Minotaur (18): PIV
    • Monitors generally had 1 or 2 guns
Weight 1.71 tons (1.74 mt)
Elevation -10 / +20 degrees
Elevation Rate Manually operated, only
Train 360 degrees
Train Rate Manually operated, only
Gun recoil N/A

Some guns were later converted for HA use. From the Australian War Memorial picture H18888 noted above, these appeared to have used very simple, extemporized mountings.

  • ^The Lord Nelson class was reduced to 18 guns during the war with the removed guns used on other warships.
  • ^HMS Dreadnought completed with 28 guns but this was increased to 31 by fitting additional guns to the roofs of the centerline turrets.

External Pictures


Data from:

  • "British Battleships of World War One" by R.A. Burt
  • "Big Gun Monitors: The History of the Design, Construction and Operation of the Royal Navy's Monitors" by Ian Buxton
  • "British Battleships: 1860 - 1950" by Oscar Parkes

Special help from Rod Butcher

Page History

28 December 2008
04 February 2014
Added ammunition stowage and number of guns
21 May 2014
Added ammunition stowage for Lord Nelson class
29 November 2015
Changed Vickers Photographic Archive links to point at Wayback Archive