The "Grenade, Hand, Anti-Tank No. 74", commonly known as the S.T. grenade or simply sticky bomb, was a British hand grenade designed and produced during the Second World War. The grenade was one of a number of anti-tank weapons developed for use by the British Army and Home Guard after the loss of many anti-tank guns in France after the Dunkirk evacuation.
The grenade was designed by a team from MIR(c) including Major Millis Jefferis and Stuart Macrae. It consisted of a glass sphere containing an explosive made of nitroglycerin and additives which added stability. When the user pulled a pin on the handle, the casing would fall away and expose the sticky sphere. Pulling another pin would arm the firing mechanism and the user would attempt to attach the grenade to an enemy vehicle. Letting go of the handle would release a lever that would activate a five-second fuse, which would then detonate the nitroglycerin compound.
The grenade had several faults in its design. The Ordnance Board of the War Department did not approve the grenade for use by the British Army, but intervention by the prime minister, Winston Churchill, led to production of the grenade. Between 1940 and 1943, approximately 2.5 million were produced. It was primarily issued to the Home Guard but was also used by British and Commonwealth forces in North Africa. It was used by Allied Forces on the Anzio Beachhead, including the First Special Service Force; as well as by Australian Army units during the New Guinea campaign. The French Resistance were also issued a quantity of the grenades.
Development
In 1938, Maj. Millis Jefferis developed an anti-tank weapon that would be ideal for irregular warfare. It would have an explosive charge deform so that it had a substantial area of intimate contact with the surface of the target. Then, when detonated, the effect of the explosion would be focused on a small area and would rupture an armoured plate.
Sappers call such a device a "poultice" or "squash head" charge. Jefferis enlisted Bauer and Schulman of the Colloid Science Department of Cambridge University, they experimented with lengths of bicycle inner tube filled with plasticine to represent the explosive. These were fitted with wooden handles and dipped in rubber solution to make them sticky. In experiments, these prototypes proved difficult to aim and only stuck to the metal bins used to represent tanks.
With the end of the Battle of France and the evacuation of the British Expeditionary Force from the port of Dunkirk between 26 May and 4 June 1940, a German invasion of Great Britain seemed likely. However, the British Army was not well equipped to defend the country in such an event; in the weeks after the Dunkirk evacuation, it could only field twenty-seven divisions. The army was particularly short of anti-tank guns, 840 of which had been left behind in France and only 167 were available in Britain; ammunition was so scarce for the remaining guns that regulations forbid even a single round being used for training purposes.
Under the circumstances, Jefferis considered that his idea might have more general application for the British Army and the Home Guard. Jefferis was in charge of a department known as , which had been created to develop and deliver weapons for use by guerrilla and resistance groups in occupied Europe. was now charged with the development of the sticky bomb. The problem of designing a sticky bomb was delegated to Robert Stuart Macrae.
Gordon Norwood, a master printer who had recruited Macrae from his former magazine publishing employer, suggested that a frangible container was needed to contain an explosive gel. He obtained a 150-Watt light bulb with which to demonstrate his point: a spherical glass flask inside a sock of woven wool: rigid when thrown, but on contact the glass would break and the bomb would deformed to the required shape. Experiments with glass flasks filled with cold porridge confirmed that this was a viable solution.
The grenade needed a delay for the thrower to get clear, so the woollen sock was covered in a sticky substance ensuring that the bomb stayed in place for a few seconds before detonating. Having covered the bomb in glue, a non-sticky handle was required. In the handle, a delay fuse was ignited by releasing a sprung lever so that a five-second time delay started as the grenade left the thrower's hand (just like the levers found on a conventional Mills bomb type hand grenade).
