BL 8 inch Howitzer Mk 6 - 8

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BL 8 inch Howitzer Mk VI, VII, VIII
US-built version of Vickers BL 8-inch Howitzer Mk 6 outside the War Museum in Helsinki, Finland
Type	Heavy howitzer
Place of origin	United Kingdom
Service history
In service	1916 - 1943
Used by	United Kingdom Australia Finland United States
Wars	World War I, World War II
Production history
Designer	Vickers
Manufacturer	Vickers Midvale Steel
Number built	678 (UK)^[1]
Specifications
Weight	3.4 tonnes
Barrel length	117.7 inches (2.990 m) Mk VI 138.4 inches (3.515 m) Mk VII, VIII

Shell	HE 200 pounds (90.72 kg)
Calibre	8-inch (203.2 mm)
Breech	Asbury interrupted screw
Recoil	hydro-pneumatic recuperator, hydraulic buffer
Carriage	wheeled, box trail
Elevation	-4° - 50° (Mk VI) 0° - 45° (Mk VII, VIII)
Traverse	4° L & R
Muzzle velocity	1,300 feet per second (396 m/s) (Mk VI) 1,500 feet per second (457 m/s) (Mk VII, VIII)
Effective range	10,745 yards (9,825 m) Mk VI 12,300 yards (11,250 m) Mk VII, VIII

The BL 8-Inch Howitzer Marks 6, 7 and 8 were a family of British artillery pieces of the First and Second World Wars, built by Vickers in Britain and by Midvale Steel in USA.

1 Design and variants
2 Combat use
3 Operators
4 Photo gallery
5 See also
6 References
7 Other Photographs
8 Surviving examples

[edit] Design and variants

Mk 6 has slid off road behind Holt tractor, WWI

8 inch was a common howitzer caliber during the First World War. The Mk 6, 7 and 8 were specifically designed as a howitzer and should not be confused with the stopgap early Marks 1 - 5 of 8-inch howitzer which used shortened and bored-out naval 6-inch gun barrels.

Mk 6

Requested in August 1915 and first delivered March 1916. It was effectively a scaled-up version of Vickers's successful 6 inch howitzer ^[2] and was 4-5 tonnes lighter than the current improvised 8 inch "howitzers". The barrel was 14.7 calibres (117.7 inches) in length, with a range of 10,745 yards (9,825 m).

Mk 7

Introduced July 1916. Mk 7 had a longer barrel (17.3 calibres, or 138.4 inches) and increased the range to 12,300 yards (11,250 m). The new barrels turned out to have short lives and suffered from cracked A tubes (the inner rifled layer of the built-up barrel).

Mk 8

Mk 8 in WWI camouflage paint at the Canadian War Museum, Ottawa

Mk 8 incorporated various small improvements and a thicker and stronger barrel.

[edit] Combat use

[edit] World War I

Gun on Vickers firing platform, and limber, gun and platform being towed

Early problems of stability on very hard or soft ground became apparent with the Mk VI, leading to the recoil system not functioning correctly. A Commission went to France to investigate, and a special level "Vickers platform" was adopted, to which the wheels and trail were secured for accurate shooting. A major change in the line of shooting required the platform to be relaid. Setting-up and adjusting the platform was labour-intensive.^[3] The US manual describes it :-^[4]

"The platform consists of wooden beams which assemble to form a triangular platform. The spade must be removed and a special bracket fitted on the trail when using this platform. This bracket travels in a groove which gives a bearing for the bracket and also provides a means of traversing the piece 52° on the platform. The main objects in the use of the firing platform are : To provide a reliable support for the wheels and rear end of the trail, so as to prevent sinking or movement when firing on soft ground; to ensure the gun remaining on the target when firing; and to provide means for shifting the trail transversely through an angle of 52° (26° each side of center). By using the traversing gear on the carriage a total traverse of 30° on each side of the center is obtainable... The carriage wheels rest on steel plates on the wheel platform and are guided by curved-steel angles which prevent lateral movement of the gun off the target when in action. When the firing platform is used, the float plate, with spade attached, which is bolted to the underside of the trail, is removed and another float plate, having a thrust bracket attached, is bolted in its place".

At the end of World War I on the Western Front Canada had 2 6-gun batteries, Australia 1, Britain 37.^[5] British 8 inch howitzer batteries serving in other theatres at the Armistice were : UK 1 (6 guns), Macedonia 1 (4 guns), and 2 guns in Palestine^[6]

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[edit] World War II

Mk 8, Bethune, April 23 1940

By the start of World War II some Mk 8 were still in use and were used in France in May to June 1940. After the Fall of France, remaining guns were used for training only. The advent of the BL 7.2-Inch howitzer meant that remaining 8 inch barrels were relined to 7.2 inch. With no guns left they were not surprisingly declared obsolete by July 1943.

[edit] Use by United States

US gunners with Mk VI gun in France

Versions of Mk 6 were manufactured in the United States by Midvale Steel and Ordnance Co, Nicetown, Pa. during World War I, initially supplied to Britain and then used to equip US forces when it entered the war.

A US Mk 8 1/2 version was also manufactured and adopted in US service from October 1918.^[7] Quoting from the US Army manual of 1920 on artillery in US service :-^[8]

"The 8 inch howitzer materiel is called the "Vickers" model of 1917, of which there are in use two types, the Mark VI and Mark VII. The main differences between the Mark VI and Mark VII being that the former has a lower muzzle velocity and consequently a shorter range than the latter, also that the Mark VII has a barrel of the "wire wound" construction, whereas the Mark VI type is of the "built up" construction... The Mark VII has lately been superseded by a Mark VIII 1/2, the difference between the two being that the powder chamber walls of the Mark VII proved to be too thin, while the Mark VIII 1/2 overcomes this defect by having thicker powder chamber walls... ... the average life of the 8-inch howitzer, Mark VI, [before the barrel needs relining] is 7,800 rounds, while that of the Mark VIII 1/2 is 3,000 rounds. The Mark VI howitzer has a muzzle velocity of 1,300 feet per second and a maximum range of 10,760 yards and is of British design and both British and American manufacture. The Mark VII howitzer has a muzzle velocity of 1,525 feet per second and maximum range of 12,280 yards and is of British design and manufacture. The Mark VIII 1/2 is an American modification of the British wire-wound Mark VIII howitzer to permit of a built up type of construction and is strictly of American manufacture. The Mark VIII 1/2 has the same muzzle velocity and range as the Mark VIII. Due to the combination of British and American manufacture, there are several types of breech mechanism in service; the two main types are the T and the French percussion type... The Mark VIII 1/2 howitzer is also of the built-up-construction type, but differs from the Mark VI howitzer in that it consists of two tubes, an inner and an outer, over which is shrunk the jacket. The jacket in this case supports the howitzer, without the use of guide rings. A breech ring is shrunk on over the jacket and carries a lug for connecting the gun to the recoil mechanism. A breech bushing similar to that of the Mark VI is fitted for the breech mechanism. The total length of this howitzer is about 12 1/2 feet [compared to Mk VI 10 1/2 feet] and its maximum range is approximately 12,360 yards. This howitzer is mounted on the Mark VII carriage".

The 58th Regiment Coast Artillery Corps (C.A.C.) was in action in France in the final days of World War I with the US-manufactured Mk 6, and 44th, 51st, and 59th Regiments were in action with British-manufactured versions.^[9]

[edit] Use by Finland

Breech of No. 188 built by Midvale used by Finland

During the Russo-Finnish Winter War Finland found itself in dire need of heavy artillery. Thirty-two "8 in Howitzer Mk 7 (Vickers Mk 6)" 8-inch howitzers were bought from the United States in 1939 but arrived too late to see action in the war. The howitzers were given the designation 203 H 17 (203 mm, Howitzer, 1917) and were first issued to three heavy artillery battalions (1st, 2nd and 3rd), which later were re-organised into six heavy artillery batteries (11th, 12th, 13th, 14th, 15th and 16th). The howitzer with its durable design was well liked by the Finnish army. Thirteen of these howitzers were lost in the battles during the summer of 1944, eight of these belonged to Heavy Artillery Battery 4 and were lost at Valkeasaari on 10 June, while the other five belonged to Heavy Artillery Battery 3, located northeast of Lake Ladoga. The howitzers were stored after the war and were stricken from the lists in the late 1960s.^[10]

[edit] Operators

Australia - 6 pieces, 54th Siege Artillery Battery, Royal Australian Artillery
Finland - 32 artillery pieces, known as 203 H 17
France
South Africa
United Kingdom - Royal Garrison Artillery (amalgamated in 1924 into Royal Artillery
United States (see History Of The Fifty-Eighth Artillery C.A.C.)

[edit] Photo gallery

Vickers 8 inch Howitzer being loaded, Western Front, 1917

howitzers of Australian 54th Siege Artillery Battery, Western Front, 1917

bringing up shells by light rail for the howitzers of Australian 54th Siege Artillery Battery, Western Front, 1917

A gun not on Vickers platform, has scotches behind wheels to steady it

[edit] See also

Wikimedia Commons has media related to:

BL 8 inch Howitzer Mk 6 - 8

[edit] References

^ Clarke 2005, page 38
^ Clarke 2005, page 38
^ Clarke 2005, page 46
^ Handbook of artillery. United States. Army. Ordnance Dept, May 1920, Page 281
^ Farndale 1986, Annex M Order of Battle France and Flanders 11th November 1918
^ Farndale 1988, Annex 1
^ Hartwell "8-inch British Howitzer"
^ Handbook of Artillery, US Ordnance Dept, May 1920, page 261, 263, 268
^ Hartwell "History of United States Army Coast Artillery Corps During World War One"
^ Paulaharju, p. 148