Britain
13.5"/45 (34.3 cm) Mark V(L)
13.5"/45 (34.3 cm) Mark V(H)
Updated 31 January 2014
Officially designated as the 12-in 'A' to conceal the increase in caliber size on previous ships, this was the largest dreadnought battleship gun in the world at the time of its introduction.  A Vickers design, these guns are sometimes suffixed as Mark V(L) and Mark V(H), which signifies the weight of the projectiles fired.  See below for further details.

The failure of the high-velocity 12"/50 (30.5 cm) Mark XI led to a reconsideration of how to achieve an increase in the destructive power of naval guns.  As a result, instead of simply raising the muzzle velocity as had been done in the past, it was now decided to maximize the weight of the shell by increasing the gun caliber and thus the size of the projectiles.  In October 1908 Vickers was requested to quote on new designs for 13" (33 cm), 13.5" (34.3 cm) and 14" (35.6 cm) guns.  Part of the design requirement for these weapons was that their projectiles were to have the same nominal residual velocity of 1,640 fps (500 mps) at 8,000 yards (7,320 m) as did projectiles from the 12"/45 (30.5 cm) Mark X.  The 13.5" (34.3 cm) design was selected in January 1909 and the first prototype was fired at Shoeburyness late that same year.

The greater momentum inherent in a heavier projectile means that it does not loose its velocity as quickly as does a lighter projectile.  So, although the muzzle velocity of the 13.5" (34.3 cm) gun was equal to that of the 12"/45 (30.5 cm) Mark X and less than that of the 12"/50 (30.5 cm) Mark XI, the striking velocity and penetration power of the new gun at long ranges was much greater than that of either of the two smaller guns.  These new 13.5" (34.3 cm) guns were found to be very reliable and accurate in service with exceptionally low barrel wear.  As the design had been given a considerable safety margin, it was decided that later ships could use a heavier shell to increase their hitting power still further.

Although these guns had a maximum elevation of 20 degrees, as built the prisms in the director and turret sights were only good to slightly over 15 degrees.  This was because prior to World War I it was expected that battles would be fought at relatively short ranges and thus the advantages of firing beyond 15,000 yards (13,700 m) were not appreciated.  Auxiliary prisms giving an extra 6 degrees and that could be attached to the existing sights were produced during World War I, but many ships still lacked these as late as the Battle of Jutland (Skagerrak).

At Dogger Bank two 13.5" (34.3 cm) APC projectiles hit German armor of 30 cm (12") without penetrating.  A third shell of this caliber hit Seydlitz on her 23 cm (9") barbette armor at an angle of 33 degrees to the normal.  Although this burst without any splinters entering the ship, flash and spalled armor fragments ignited 62 propellant charges and this fire burned out both stern turrets, killing 165 crewmen.  Seydlitz was hit again by a 13.5" (34.3 cm) projectile almost the same way during the Battle of Jutland (Skagerrak) and this again holed the armor but was kept out except for flash which ignited four charges.

During World War II three of these guns were used as railway artillery in the Dover area and were supplied with super charges.  A further three guns were relined to 8" (20.3 cm) as a "not very successful super-velocity gun - a remarkable waste of effort" (John Campbell).  Four guns together with their slides and cradles from the scrapped battlecruiser HMS Tiger were sold to Turkey before the start of World War II, but none were ever delivered.

The "steel choke" problem first found on the 12"/35 (30.5 cm) Mark VIII was finally fixed in the later models of these guns by the introduction of a slow taper fit between the inner A and A tubes.  The locating shoulders, which in the earlier guns were well forward and overly concentrated longitudinal stress towards the muzzle, were moved well back in the new guns.

These guns were of the standard wire-wound construction and the first 67 of the 206 guns produced still had the forward locating shoulders and lacked the taper fit.  54 guns were still in existence in 1939 along with six turrets removed from HMS Tiger and HMS Iron Duke and placed in storage at Rosyth.

WNBR_135-45_mk5_Monarch_pic.jpg

HMS Monarch
This ship carried the 13.5"/45 (34.3 cm) Mark V(L)
Bain News Service Photograph
Library of Congress Photograph ID LC-DIG-ggbain-16828

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Click here for additional pictures
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Gun Characteristics
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Designation 13.5"/45 (34.3 cm) Mark V(L)
13.5"/45 (34.3 cm) Mark V(H)
Ship Class Used On
(see Note)
(L):  Orion, Lion and Conqueror classes
(H):  King George V, Iron Duke, Queen Mary, Tiger, Ajax and Benbow classes
Date Of Design 1909
Date In Service 1912
Gun Weight Without Breech:  167,776 lbs. (76,102 kg)
Gun Length oa 625.9 in (15.900 m)
Bore Length 607.5 in (15.431 m)
Rifling Length 509.6 in (12.943 m)
Grooves 68
Lands N/A
Twist Uniform RH 1 in 30
Chamber Volume 19,650 in3 (322.0 dm3)
Rate Of Fire 1.5 - 2 rounds per minute
Note:  As no spare Mark VI guns had been manufactured, one Mark V(H) gun was carried by HMS Erin for a short period.
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Ammunition
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Type Bag
Projectile Types and Weights
(see Note 2)
Light
   APC Mark IIa - 1,266.5 lbs. (574.5 kg)
   APC Mark IVa (Greenboy) - 1,257 lbs. (570.2 kg)
   APC 8/12crh - 1,250 lbs. (567.0 kg)
   CPC - 1,250 lbs. (567.0 kg)
   HE - 1,250 lbs. (567.0 kg)

Heavy
   APC Mark Ia - 1,400 lbs. (635.0 kg)
   APC Mark IIIa (Greenboy) - 1,410 lbs. (639.6 kg)
   CPC - 1,400 lbs. (635.0 kg)
   HE - 1,400 lbs. (635.0 kg)

Railway Projectile
   APC - 1,250 lbs. (567 kg)

Bursting Charge Light
   APC Mark IIa - 40 lbs. (18.1 kg)
   APC Mark IVa - 29.5 lbs. (13.4 kg)
   APC 8/12crh - N/A
   CPC - 117.4 lbs. (53.3 kg)
   HE - 176.5 lbs. (80.1 kg)

Heavy
   APC Mark Ia - 44.5 lbs. (20.2 kg)
   APC Mark IIIa - 33 lbs. (15.0 kg)
   CPC - 117.5 lbs. (53.3 kg)
   HE - 176.5 lbs. (80.1 kg)

Projectile Length
(see Note 5)
Light
   N/A

Heavy
   APC Mark Ia - 49.6 in (126 cm)
   APC Mark IIIa - 49.2 in (125 cm)
   CPC - 59.8 in (151.9 cm)
   HE - N/A

Propellant Charge - Ships APC (Light):  293 lbs. (133 kg) MD45
APC (Heavy):  297 lbs. (135 kg) MD45
Propellant Charges - Railway Standard Charge
   299 lbs. (135.6 kg) SC 280

Super Charges
   APC (Light):  400 lbs. (181.4 kg) SC 390
   APC (Heavy):  423 lbs. (191.9 kg) SC 450

Muzzle Velocity
(standard charges)
APC (Light):  2,582 fps (787 mps)
APC (Heavy):  2,491 fps (759 mps)
Muzzle Velocity
(super charges)
APC (Light):  2,950 fps (899 mps)
APC (Heavy):  2,830 fps (863 mps)
Working Pressure Light - 18 tons/in2 (3,150 kg/cm2)
Heavy - 20 tons/in2 (2,835 kg/cm2)
Approximate Barrel Life Light - 450 rounds
Heavy - 220 rounds
Ammunition stowage per gun
(see Note 6)
King George V class:  112 rounds
Iron Duke:  100 rounds
Orion, Lion, Queen Mary and Tiger classes:  80 rounds
Others:  N/A
Notes:

1) The sources below disagree as to the muzzle velocity for these guns.  I have chosen to use those values given in "British Naval Guns 1880-1945 No 2."

2) Projectiles were nominally 4crh.  The railway guns used a new 1,250 lbs. (567 kg) AP shell of 8/16crh which achieved a much greater range.

3) Super charges were used solely by the railway guns.

4) The muzzle velocities given above are for new guns.  When worn and due for replacement, the Mark V(L) gun had a muzzle velocity of 2,100 fps (640 mps).

5) The projectile lengths given are average numbers.  There were as many as five different manufacturers for these munitions, each producing a slightly different projectile from the others.

6) Ammunition storage given above are the design figures.  More rounds were added during the war.  Lion was originally given 24 APC, 28 CPC, 28 HE and 6 shrapnel or 86 rounds total per gun.  During the early part of the war, this was changed to 110 rounds per gun of 33 APC, 38 CPC and 39 HE.  By the time of Jutland (Skagerrak), she carried 66 APC, 22 CPC and 22 HE.  The final war outfit was 77 APC (Greenboys) and 33 CPC per gun.  Other 13.5" (34.3 cm) battlecruisers had similar outfit numbers and changes.

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Range With 1,250 lbs. (567 kg) APC Mark IIa Shell
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Elevation
Range
MV = 2,550 fps (777 mps)
Striking Velocity
Angle of Fall
1.14 degrees
2,500 yards (2,290 m)
2,326 fps (709 mps)
1.23
2.40 degrees
5,000 yards (4,570 m)
2,117 fps (645 mps)
2.73
3.88 degrees
7,500 yards (6,860 m)
1,931 fps (589 mps)
4.66
5.55 degrees
10,000 yards (9,140 m)
1,750 fps (533 mps)
7.08
7.47 degrees
12,500 yards (11,430 m)
1,610 fps (491 mps)
10.11
9.64 degrees
15,000 yards (13,720 m)
1,487 fps (453 mps)
13.78
12.08 degrees
17,500 yards (16,000 m)
1,395 fps (425 mps)
18.00
14.78 degrees
20,000 yards (18,290 m)
1,332 fps (406 mps)
22.73
20.00 degrees
23,820 yards (21,780 m)
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Range With 1,400 lbs. (635 kg) APC Mark Ia Shell
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Elevation
Range
MV = 2,500 fps (762 mps)
Striking Velocity
Angle of Fall
1.17 degrees
2,500 yards (2,290 m)
2,305 fps (703 mps)
1.23
2.48 degrees
5,000 yards (4,570 m)
2,117 fps (645 mps)
2.75
3.95 degrees
7,500 yards (6,860 m)
1,940 fps (591 mps)
4.65
5.60 degrees
10,000 yards (9,140 m)
1,783 fps (543 mps)
7.03
7.50 degrees
12,500 yards (11,430 m)
1,643 fps (501 mps)
9.90
9.60 degrees
15,000 yards (13,720 m)
1,524 fps (565 mps)
13.40
12.05 degrees
17,500 yards (16,000 m)
1,429 fps (436 mps)
17.5
14.75 degrees
20,000 yards (18,290 m)
1,365 fps (416 mps)
22.00
20.00 degrees
23,740 yards (21,710 m)
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Range as Railway Gun
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Elevation With 1,250 lbs. (567 kg) 8/16crh APC Shell
Range @ 40 degrees
Super charges
48,900 yards (44,700 m)
Elevation With 1,400 lbs. (635 kg) APC Shell
Range @ 40 degrees
Super charges
40,600 yards (37,120 m)
Note:  Ranges with standard charges for the 1,400 lbs. (635) APC shells would be equivalent to those in the previous table.
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KC-type Armor Penetration with 1,250 lbs. (567 kg) AP Shell
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Range
Side Armor
Deck Armor
Striking Velocity
0 yards (0 m)
17.3" (439 mm)
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2,700 fps (823 mps)
10,000 yards (9,144 m)
12.2" (310 mm)
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1,900 fps (579 mps)
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KC-type Armor Penetration with 1,400 lbs. (635 kg) AP Shell
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Range
Side Armor
Deck Armor
Striking Velocity
0 yards (0 m)
17.3" (439 mm)
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2,500 fps (762 mps)
10,000 yards (9,144 m)
12.5" (318 mm)
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1,850 fps (564 mps)
Notes:

1) Data in both tables is from "British Battleships of World War Two."

2) The penetration figures in these tables are for an uncapped AP shell striking the plate at 90 degrees, i.e., with the axis of the shell perpendicular to the face of the plate.  A capped shell would give about 10 to 20% improvement at low velocities and about 30 to 50% at high velocities.

3) Note that the muzzle velocity for the 1,250 lbs. (567 kg) APC shell in the upper table is much higher than that given in most references.  For that reason, I believe that these to be proofing values and not what would be achieved in service.

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Mount / Turret Data
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Designation
(see Note 1)
Two-gun Turrets
   Orion (5), Lion (4) and Princess Royal (4):  Mark II
   Queen Mary (4) and King George V (5):  Mark II*
   Iron Duke (5) and Tiger (4):  Mark II**
   Conqueror (5):  Mark III
   Ajax (5):  Mark III*
   Benbow (5):  Mark III**
Weight Mark II:  600 tons (610 mt)
Others:  N/A
Elevation
(see Note 5)
Ships:  -3 / +20 degrees

Railway:  0 / +40 degrees

Rate of Elevation Mark II and Mark II*:  3 degrees per second
Mark II**, Mark III and Mark III*:  5 degrees per second
Train
(see Notes 6 and 7)
Forward and aft turrets:  about -150 / +150 degrees
Q turret:  about 30 to 150 degrees on either side
Rate of Train N/A
Gun Recoil N/A
Loading Angle Any
Notes:

1) Orion was the first British dreadnought with all mountings on the centerline and with superfiring turrets fitted on the bow.  Mountings with a single asterisk (*) after the Mark Number indicates that they were modified to handle the 1,400 lbs. (567 kg) projectiles.  Mountings with a double asterisk (**) after the Mark number indicate a further modification to increase the elevation speed.

2) The Mark II turrets were very similar to the previous BXI mountings used for the 12"/50 (30.5 cm) guns of the St. Vincent class.  As the designers of the Mark II mounts kept approximately the same dimensions as those for the BXI, the Mark II mounts were cramped and compromises in shell handling were accepted.  These mounts were equipped with the newly invented swashplate training engine which gave them smoother training movements.  Two 7-cylinder swash plate engines were provided for each mounting.

3) Stowage for eight rounds per gun were provided in the Mark II and II* gunhouse, with two powered derricks provided to lift the shells.  Bins for six rounds per gun were arranged in the working chamber below the gunhouse and an emergency shell and cordite supply route was built into the main trunk.

4) The Mark III turrets were the first large-caliber mountings to be designed by the Coventry Ordnance Works.

5) As built the prisms in the director and turret gunsights controlling these mountings allowed ranging only up to an elevation of +15' 21".  By the time of Jutland (Skagerrak), removable 6 degree "super elevation" prisms that could be attached to the existing director sights and to the center position turret sight had been given to some ships but this process was not completed until 1917.

6) Superfiring turrets could not fire within 30 degrees of the axis because the blast effects would have penetrated into the lower turrets through the sighting hoods.

7) Q turret on Tiger was in a more favorable position, increasing its firing arc to 60 degrees before the beam and 90 degrees abaft it on either side, although it could not fire directly aft below about 10 degrees of elevation.

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Data from
"The Grand Fleet:  Warship Design and Development 1906-1922" by D.K. Brown
"British Battleships of World War One" by R.A. Burt
"Naval Weapons of World War Two," "Jutland:  An Analysis of the Fighting," "The Battle of Tsu-Shima" article in "Warships Volume II," "Warship Special 1:  Battle Cruisers" and "British Naval Guns 1880-1945 No 2" article in "Warships Volume V" all by John Campbell
"Battleship Design and Development 1905-1945" by Norman Friedman
"The Big Gun:  Battleship Main Armament 1860-1945" by Peter Hodges
"The Admiralty Regrets:  British Warship Losses of the Twentieth Century" by Paul Kemp
"British Battleships:  1860 - 1950" by Oscar Parkes
"British Battleships of World War Two" by Alan Raven and John Roberts
"Battlecruisers" by John Roberts
"The Royal Navy in Old Photographs" by Wilfrid Pym Trotters
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ADM 186/169
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Special help from Neil Stirling and Anthony Lovell of Dreadnought Project
Page History

04 December 2006 - Benchmark
01 May 2009 - Added picture of Monarch
29 December 2011 - Added information about hits on Seydlitz and ammunition outfits on battlecruisers
11 February 2012 - Updated to the latest template
25 November 2012 - Corrected comment about auxiliary prisms
31 January 2014 - Added additional pictures page