Combat Tank, Light-31-5

CTL-3: General
Date of first acceptance June 1936 Total acceptances 5
Manufacturer Marmon-Herrington Co. Crew 2 men
CTL-3: Dimensions
Combat weight 9500lbs
CTL-3: Armament
Type Mount Traverse Elevation
Three .30cal MG Ball mounts in hull front Manual Manual
CTL-3: Armor
CTL-3: Automotive
Engine Lincoln 12 cylinder vee gasoline
Horsepower 110
CTL-3: Suspension
Type Road wheels Track return rollers
Semi-elliptical leaf spring 2 bogies/track;
2 dual wheels/bogie
1 dual/track
Drive sprockets Idlers Shock absorbers
Front drive Adjustable at rear of track None
CTL-3: Track
Center guide band type
Width 10.5"
CTL-3: Performance
Max level road speed 33mph
Max trench 50"
Max vertical obstacle 18"
Max fording depth 40"
Cruising range 125mi

The CTL-3 was a turretless vehicle, and the three machine guns were mounted in the vertical portion of its stepped hull front plate. A long, sloping rear deck covered the engine, and the crew sat in a raised box near the front of the tank that provided three viewing ports on its front, two on the rear, and one on each side. Driving controls were fitted to both crew stations.

In 1938, the improved CTL-3A debuted with an improved suspension. The original suspension featured a longer leaf spring that supported the first and last road wheels, while the middle two were sprung on a shorter leaf spring. The CTL-3A reworked this to incorporate two long leaf springs behind a frame. The CTL-3A was powered by a 124hp Hercules 6-cylinder engine and weighed 10,900lb (4940kg). Five CTL-3As were delivered to the Marines in June 1939, and the original five CTL-3 tanks were brought up to CTL-3A standard.

At least five CTL-3s were rebuilt in 1941 with a new vertical volute spring suspension similar to that found on the M2A4 light tank. Two two-wheel bogies were installed on each side, and a single return roller was mounted between them. The bogie frames had track skids mounted on their tops. A 14-tooth front drive sprocket turned the outside guide tracks which were made up of 54 shoes on each side. These tanks were designated CTL-3M.



  1. Crismon, Fred W. U.S. Military Tracked Vehicles. Osceola, WI: Motorbooks International, 1992.
  2. Estes, Kenneth W. Marines Under Armor. Annapolis, MD: Naval Institute Press, 2000.
  3. Spoelstra, Hanno. "Marmon-Herrington Military Vehicles: Tanks." Marmon-Herrington Military Vehicles. 5 Dec 2013 <>.
  4. Hunnicutt, R.P. Stuart: A History of the American Light Tank, volume 1. Navato, CA: Presidio Press, 1992. Reprinted with permission from Stuart, R.P. Hunnicutt ©1992, available from Presidio Press, 505B San Martin Drive, Suite 160, Navato, CA 94945.
  5. Kirk, William. "Light Tanks." TANKS! 13 Feb 2003. 5 Dec 2013 <​LightTanks.html>. TANKS!
Last updated 29 Sep 2016.
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