| No. 73 | |
|---|---|
Hand Percussion Grenade (anti-tank No 73 Mark I)[1] |
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| Type | Anti-tank grenade |
| Place of origin | United Kingdom |
| Service history | |
| In service | 1940-1941 1943-?1945 |
| Used by | United Kingdom |
| Wars | Second World War |
| Specifications | |
| Weight | 4.5 pounds (2.0 kg) |
| Length | 11 inches (280 mm) |
| Diameter | 3.5 inches (89 mm) |
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| Filling | Polar ammonal gelatine dynamite or nitrogelatine |
| Filling weight | 3.5 pounds (1.6 kg) |
| Detonation mechanism |
Impact |
The No. 73 grenade, also known as the Thermos or Woolworth bomb,[2] was a British anti-tank grenade used during the Second World War. It got its nickname from the resemblance to a Thermos flask.
Contents |
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.[3] 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.[4] 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 forbade even a single round being used for training purposes.[4] As a result of these shortcomings, a number of new anti-tank weapons had to be developed to equip the British Army and the Home Guard with the means to repel German armoured vehicles.[5] Many of these were anti-tank hand grenades, large numbers of which could be built in a very short space of time and for a low cost.[2] They included the Grenade, Hand, Anti-tank No. 74, also known as the 'Sticky bomb', which was coated with a strong adhesive and 'stuck' to a vehicle, and the No. 76 Special Incendiary Grenade, essentially a British variation on the Molotov cocktail.[6] Ian Hogg states that the "simplest of these grenades" was the No. 73 grenade, which was known under a variety of names, including the hand percussion grenade,[7] the Thermos bomb and the Woolworth bomb.[2]
The No. 73 grenade had a roughly cylindrical shape and plastic screw-on cap,[8] similar to that of a Thermos flask, from which the 'Thermos bomb' nickname was derived.[9] It was approximately 3.5 inches (89 mm) in diameter and 11 inches (280 mm) in length,[10] and weighed some 4.5 pounds (2.0 kg). Its explosive content consisted of 3.5 pounds (1.6 kg) of polar ammonal gelatine dynamite or nitrogelatine - both of which were easily flammable and could be detonated by the impact of small-arms fire.[8] When thrown at a tank or other vehicle, a weighted tape held in the users hand unravelled and pulled free a safety pin, which was attached to a No. 69 "All-ways" fuse; this armed and then subsequently detonated the grenade.[11] However, its considerable weight meant that it could only be thrown short distances,[2] limiting its range to between 10 yards (9.1 m) and 15 yards (14 m),[8] and its detonation could injure the user if they did not find cover before it detonated.[2] It was able to penetrate 2 inches (51 mm) of armour,[12] and "damage severely any light tank."[7] However, it was best used against the tracks of a tank, which it could easily blow off[8] and force its crew to waste time by stopping and repairing it.[13]
The No. 73 grenade was first issued in the last months of 1940, but it was rarely used as an anti-tank grenade; instead the fuse was usually removed and it was used as a demolition charge. It was withdrawn from service within a year, and reissued again in 1943 for the express purpose of being used for demolition work.[8]
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