The Mark IX tank was a British
armoured fighting vehicle
An armoured fighting vehicle (British English) or armored fighting vehicle (American English) (AFV) is an armed combat vehicle protected by vehicle armour, armour, generally combining operational mobility with Offensive (military), offensive a ...
from the
First World War
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
. It was the world's first specialised
armoured personnel carrier
An armoured personnel carrier (APC) is a broad type of armoured military vehicle designed to transport personnel and equipment in combat zones. Since World War I, APCs have become a very common piece of military equipment around the world.
Acc ...
(APC).
Development
During the first actions with
tank
A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and battlefield mobility provided by tracks and a powerful engine; ...
s, it became clear that
infantry
Infantry, or infantryman are a type of soldier who specialize in ground combat, typically fighting dismounted. Historically the term was used to describe foot soldiers, i.e. those who march and fight on foot. In modern usage, the term broadl ...
often could not keep up with the tanks; not because soldiers were too slow—the early tanks themselves could only move at a walking pace—but because soldiers on foot remained vulnerable to
machine gun fire, though tanks had been invented to solve that problem. On many occasions, positions gained at great cost were immediately lost for lack of infantry to consolidate. It was thought this problem might be solved by cramming a few infantry soldiers into each tank, but the atmosphere inside was of such poor quality that the soldiers became ill and eventually lost consciousness. When exposed to fresh air again, the crew were incapacitated for about an hour while recovering from the noxious fumes inside the tank. They would be sick and suffer from severe headaches.
In the summer of 1917, at the same time as another 'carrier' tank, the
Gun Carrier Mark I
The Gun Carrier Mark I was a British vehicle of the First World War. The gun carrier was designed to transport a 6-inch howitzer or a 60-pounder gun forward soon after an attack to support infantry in advanced positions. Gun carriers were first ...
, was under development, Lieutenant
G.J. Rackham was ordered to design an armoured vehicle specifically for troop transport. He cooperated with
Eustace Tennyson d'Eyncourt, the chairman of the
Landships Committee. Design was complicated by a demand that the vehicle could be fitted with
sponson
Sponsons are projections extending from the sides of land vehicles, aircraft or watercraft to provide protection, Instantaneous stability, stability, storage locations, mounting points for weapons or other devices, or equipment housing.
Watercra ...
s, converting it into a more modern battle tank than the
Mark V tank
The British Mark V tank was an upgraded version of the Mark IV tank.
The tank was improved in several aspects over the Mark IV, chiefly the new steering system, transmission and 150 bhp engine, but it fell short in other areas, particular ...
, in case the
Mark VIII tank
The Mark VIII tank also known as the Liberty or The International was a British-American tank design of the First World War intended to overcome the limitations of the earlier British designs and be a collaborative effort to equip France, the U ...
design proved a failure and the type was still designated as a tank, a 'Mark IX' to succeed the Mark VIII but that requirement was soon dropped due to its complexity.
[Fletcher (2001) p. 167]
Prototype construction and production
In September 1917
Armstrong, Whitworth & Co. in
Newcastle-upon-Tyne
Newcastle upon Tyne, or simply Newcastle ( , Received Pronunciation, RP: ), is a City status in the United Kingdom, cathedral city and metropolitan borough in Tyne and Wear, England. It is England's northernmost metropolitan borough, located o ...
began constructing two prototypes of a pure transport vehicle that would become the Mark IX, which could also serve as a supply tank. The prototypes were approved the following year, at a time when it had become clear that a possible alternative, the stretched
Mark V* tank, was unsuited for infantry transport. Two hundred Mark IXs were ordered from the tractor manufacturer
Marshall, Sons & Co. of
Gainsborough, Lincolnshire
Gainsborough () is a market town and civil parish in the West Lindsey Non-metropolitan district, district of Lincolnshire, England. The population was 20,842 at the 2011 census, and estimated at 23,243 in 2019. It lies on the east bank of the ...
but by the end of the Great War only three had been finished, out of a total ultimate production run of thirty-four.
[Fletcher (2001) p. 169] A specially designed sledge developed by the tank workshop in France, that allowed an additional of stores to be hauled, was tried.
Description

As there was no time for a completely new design, the Mark IX was based on the Mark V, with the hull lengthened to . The 150 hp Ricardo engine was moved to the front, the gearbox to the back and the suspension girders left out entirely. This created an inner space long and wide, enough room for thirty (officially even fifty) soldiers or ten tons of cargo. To ensure sufficient stiffness for the chassis, the floor was reinforced by heavy transverse girders. The infantry inside had to contend with the control rods for the gears running along the roof and the drive shaft through the middle. Unfortunately for the infantrymen, no seats were built in for them in the tank.
[Fletcher (2001) p. 168]
The crew proper consisted of a driver sitting on the left and a commander sitting to the right of him (the first time in a British tank making this concession to the
prevailing traffic conditions in France), a mechanic, and a machine gunner who could man a gun in a hatch at the rear. A second machine gun was fitted in the front. Designed as an armoured personnel carrier, the type had elements of an
infantry fighting vehicle
An infantry fighting vehicle (IFV), also known as a mechanized infantry combat vehicle (MICV), is a type of armoured fighting vehicle and armoured personnel carrier used to carry infantry into battle and provide direct fire, direct-fire suppo ...
, as along each side of the hull there were eight
loopholes, through which the soldiers could fire their rifles. Four of the total of sixteen loopholes were in the four oval doors (two to each side) through which soldiers could embark and disembark.
Despite the use of thinner——
armour
Armour (Commonwealth English) or armor (American English; see American and British English spelling differences#-our, -or, spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, e ...
, the operational weight was still and the speed only . The tank could also carry supplies in a tray on the roof behind the commander's armoured observation turret (being the highest point at ), while towing up to three loaded sledges. Rackham tried to improve internal conditions by putting a large silencer on the roof together with ventilation fans; but there was still no separate engine compartment and it is, therefore, questionable whether the project achieved the goal of a vehicle capable of delivering a squad of infantry in fighting condition, even given the severely limited operational range of the Mark IX.
Operational history and project
The Mark IXs were used for some years after the war. Pictures exist of vehicles carrying the designation "IC" painted on their hulls, probably indicating they were indeed used as "Infantry Carriers".
The type – named ''The Pig'' after the low front track silhouette that gave a snout-like appearance
– was used as the basis of two conversions: one of the first three built was used as an armoured ambulance,
while another was rebuilt as an amphibious tank by the staff of the test base at
Dollis Hill
Dollis Hill is an area in northwest London, which consists of the streets surrounding the Gladstone Park, London, Gladstone Park. It is served by a London Underground station, Dollis Hill tube station, Dollis Hill, on the Jubilee line, providi ...
.
[David Fletcher, 2001, ''The British Tanks 1915-19'', The Crowood Press, p. 178]
"The Duck" Amphibious Conversion

Already a bulky vehicle – the probable reason the Mark IX was selected as the basis for an amphibious tank – its
displacement
Displacement may refer to:
Physical sciences
Mathematics and physics
*Displacement (geometry), is the difference between the final and initial position of a point trajectory (for instance, the center of mass of a moving object). The actual path ...
was improved by fitting drums at the front and sides. Long wooden boards were attached to the track links but at one side of the board only; as they reached the curve of the track they would project, acting as paddles. Pictures were made of a floating tank in
Hendon Reservoir on 11 November 1918, the day of the Armistice. According to oral tradition, this vehicle was named ''The Duck'' but there are doubts as to its veracity. The photographs show that a large rectangular superstructure had been placed around the cab and from this superstructure pipes projected upwards, likely the outlets of
bilge pumps. The vehicle was for the occasion manned by Navy personnel.
The last surviving Mark IX now resides at
The Tank Museum
The Tank Museum (previously the Bovington Tank Museum) is a collection of armoured fighting vehicles at Bovington Camp in Dorset, South West England. It is about north of the village of Wool and west of the major port of Poole. The collectio ...
,
Bovington.
Gallery
Mark IX tank at Dollis Hill.jpg, Mark IX at Dollis Hill, prior to the amphibious modifications.
Mark IX Tank Amphibious Conversion in Welsh Harp Reservoir.jpg, Mark IX Tank Amphibious Conversion in Welsh Harp Reservoir, with all of its passengers out on top
Mark IX Amphibious Conversion, with two men alongside it, at Welsh Harp Reservoir.jpg, Mark IX Amphibious Conversion, with two men alongside it, at Welsh Harp Reservoir
Side View of the Mark IX during its amphibious conversion trials at Welsh Harp Reservoir.jpg
File:Mk IX Tank Interior.jpg, Inside the troop compartment of the preserved MK IX tank at Bovington.
Notes
References
*
*''TANK: A History of the Armoured Fighting Vehicle'' Kenneth Macksey and John H Batchelor (1970) Page 46
*''TANK Facts and Feats: A Guinness Superlatives Book'' Kennith Macksey 3rd Edition (1980) Page 61
*''Armoured Fighting Vehicles of World Wars I and II'' by Jack Livesey, Anness Publishing Ltd Page 121
Tank Mark IX No. 936 (E1949.364)tankmuseum.org
{{WWI British AFVs
World War I tanks of the United Kingdom
Military vehicles introduced in the 1910s
Armoured personnel carriers of the United Kingdom