Tank Recovery Vehicle M311-6

M31: General
Date of first acceptance December 1942 Total acceptances 509
(109 converted to full-track prime mover M33)
Manufacturer Baldwin Locomotive Works Crew 6 men
M31: Dimensions
Combat weight 60,000lbs
27,200kg
Height with boom stowed 117"
297cm
Length with boom stowed 317"
805cm
Width over side doors 107"
272cm
Tread 83"
211cm
Ground clearance 17.125"
43.498cm
Turret ring diameter 54.5"
138cm
Ground pressure, zero penetration 12.5psi
.878kg/cm²
M31: Armament
Type Mount Ammunition Traverse Elevation
.30cal M1919 MG AA mount on turret 2,000 rounds 360°
(manual)
Manual
.30cal M1919 MG Fixed in hull left front
M31: Armor
Assembly
Riveting
Hull
Rolled homogeneous steel
Location Thickness Angle from vertical
Upper front 2.0"
5.1cm
30°
Middle front 1.5"
3.8cm
53°
Lower front 2.0"
5.1cm
0° to 45°
Sides 1.5"
3.8cm
Rear 1.5"
3.8cm
0° to 10°
Top .50"
1.3cm
83° to 90°
Front floor 1.0"
2.5cm
90°
Rear floor .50"
1.3cm
90°
Turret
Cast homogeneous steel
Location Thickness Angle from vertical
Front 2.0"
5.1cm
47°
Sides 2.0"
5.1cm
Rear 2.0"
5.1cm
Top .875"
2.22cm
90°
M31: Automotive
Engine Continental R975 C1; 9 cylinder, 4 cycle, static radial, supercharged gasoline
Horsepower Net: 350@2,400rpm
Gross: 400@2,400rpm
Torque Net: 800 ft-lb@1,800rpm
Gross: 890 ft-lb@1,800rpm
Fuel capacity 185gal
700L
Transmission Synchromesh, 5 speeds forward, 1 reverse
Steering Controlled differential, steering levers
Brakes Mechanical, external contracting
M31: Suspension
Type Road wheels Track return rollers
Vertical volute spring 3 bogies/track;
2 wheels/bogie
1 on top of each bogie
Drive sprockets Idlers Shock absorbers
13-tooth front drive Adjustable at rear of track None
M31: Track
T41
Outside guide, double pin, smooth, rubber
Width 16.0"
40.6cm
Pitch 6"
15cm
Shoes/track 79 Ground contact length 147"
373cm
T48
Outside guide, double pin, chevron, rubber
Width 16.56"
42.06cm
Pitch 6"
15cm
Shoes/track 79 Ground contact length 147"
373cm
T49
Outside guide, double pin, parallel bar, steel
Width 16.56"
42.06cm
Pitch 6"
15cm
Shoes/track 79 Ground contact length 147"
373cm
T51
Outside guide, double pin, smooth, rubber
Width 16.56"
42.06cm
Pitch 6"
15cm
Shoes/track 79 Ground contact length 147"
373cm
M31: Performance
Max level road speed 25mph
40kph
Max trench 89"
230cm
Max grade 60% Max vertical obstacle 24"
61cm
Min turning diameter 62'
19m
Max fording depth 42"
110cm
Cruising range ~110mi
~180km

The M31 was based on the medium tank M3. The 75mm gun rotor was replaced by a door fitted with a dummy tube, and a crane replaced the 37mm gun in the turret. The turret was rotated to the rear when not in use, and a dummy 37mm tube was attached to the turret rear to keep the appearance of a fighting vehicle. The turret machine gun mount was the British style seen on the cruiser tank Grant I instead of the normal Lee cupola. The crane could lift 10,000lbs (4,500kg) without the supporting boom jacks extended, 12,000lbs (5,400kg) with the jacks attached to the front hull, or 30,000lbs (14,000kg) with the support legs on the ground. A 60,000lb (27,000kg) capacity winch was added in the fighting compartment, and the cable was spooled out of the turret and over the crane boom or out the rear of the TRV. Tool boxes were also added to the rear sponsons and above the dummy 75mm gun. M31B1, introduced in October 1942, was based on the M3A3 Lee, and the conversion was similar to the M31 except that the power takeoff on the diesel TRVs was at the front and powered by the engine, rather than being at the left rear and driven by the transmission on the static radial, supercharged gasoline-engined vehicles. This difference necessitated some modifications to the winch operator's position and controls. Two hundred ninety-six M31B1s were manufactured by Baldwin Locomotive works. M31B2, also built by Baldwin, was based on the M3A5 Lee.

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References

  1. Hunnicutt, R.P. Sherman: A History of the American Medium Tank. Navato, CA: Presidio Press, 1994. Reprinted with permission from Sherman, R.P. Hunnicutt ©1994, available from Presidio Press, 505B San Martin Drive, Suite 160, Navato, CA 94945.
  2. Catalogue of Standard Ordnance Items, second edition 1944, volume I: Tank and Automotive. Washington, D.C.: Office of the Chief of Ordnance, Technical Division, 1 June 1945.
  3. TM 9-2800 Standard Military Motor Vehicles. Washington, DC: War Dept., 1 Sep 1943.
  4. Chamberlain, Peter, and Chris Ellis. British and American Tanks of World War Two. Frome, England: Cassell & Co., 2000.
  5. Crismon, Fred W. U.S. Military Tracked Vehicles. Osceola, WI: Motorbooks International, 1992.
  6. Siemers, Cary. "USA's M3, M3A1, M3A2, M3A3, M3A4, M3A5 Medium Tanks." World War II Tanks & Vehicles and Advanced Squad Leader. 28 Jan 2001. 20 Feb 2001 <http://www.shadowsfolly.com/WWII/USA/MediumTankM3.htm>.
Last updated 11 Apr 2023.
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© Copyright 2001-23 Chris Conners