Anti-Tank Squirter

I recently found a file in an archive that talked about a British anti-tank weapon that, so far as I can tell, hasn't been mentioned before. It was (eventually) known as the 'Projector, AT Portable, No1, Mk.1', although it went through several names in its time, such as the Jet, AT, Mk.1, Squirts, AT and the name that will give the game away, Projector, Gas, AT.

Yes, it's another one of those weapons designed to fire hydrogen cyanide, or HCN, that the British seem to have had such an obsession with. To date I've been unable to unearth a picture of this contraption, however, I do have a description of it.

To give an idea of scale this Italian flamethrower, carried by a Finn, has a 12L capacity tank.

The HCN was stored in a 11 litre tank, although this was only filled with 9L. This was, presumably, carried on the back, as at the bottom of the tank a pipe was attached which led to a nozzle which the operator held. This nozzle had a built-in battery which linked to a cordite charge inside the tank. There was an aluminium foil disk sealed over the bottom of the tank, between the pipe attachment and the gas storage. When the cordite charge was fired the massive increase in pressure would rupture the foil and allow the gas to be pushed through the nozzle, dumping the entire contents in one giant squirt.

ICI Cassel in Billingham, where the HCN was produced.

To reload you just replaced the cordite charge and the foil disk, then recharged the gas tank. The gas was not pressurised, indeed filling in ICI's factory was done by pouring the HCN into the tanks. There were considerable safety measures in place, however. In the filling room there was a constant exchange of air, and all the workers wore masks fed from external air.

Inside Cassel, although one of the less sensitive areas. Here the workers are splitting Brine into sodium and Chlorine

At least fourteen Squirts were produced, although the initial prototype run was to be 180. At least two, uncharged, equipment’s were sent to the No 2 Anti-Gas Laboratory in Canada, the others were sent to Porton Down. The Canadians immediately ran into a problem with their two equipment’s (with serial numbers 2a and 3a). On the first Squirt they charged it was found the aluminium foil became corroded. This was reported to the UK and investigations were carried out throughout 1942. These included a study by Dr U. R. Evans of Cambridge University. Dr Evans was an expert in the field of corrosion of aluminium. By 1943 it was determined that the corrosion effect had come from the HCN the Canadians used. They had used US Standard HCN, while the British used British Standard. The difference was the stabilizing element, consisting of just 0.2% of the mixture. The US used sulphuric acid, while the British used oxalic acid.

Men of the Royal Ulster Rifles armed with a 2" mortar

In mid to late 1942 twelve projectors were issued to the Royal Ulster Rifles for user trials. These turned up a number of minor defects that Porton Down worked into the final production of the Squirt. It is possible that the choice of the Royal Ulster Rifles gives us a clue as to how the British saw these weapons. The regiment were glider troops, and so expected to run into enemy forces, without the guarantee of heavier anti-tank weapons such as anti-tank guns. At the time the Boys Rifle would have been the only choice, and that was seen as pretty useless. Equally, the PIAT was still under development. The total production run of just a proposed 360 Squirts also indicates that it wouldn't have been for general issue.

A series of trials were held against a Churchill MK.III. In the first test the vehicle was fully closed down, which provided the most resistance against the Squirt, although the summary of the report doesn’t say if this would cause casualties. Opening either the commanders hatch, or the side doors would result in the crew being killed as this was when the tank was most vulnerable. Curiously opening both the commanders hatch and the side doors left the tank less vulnerable as it allowed a draft through the tank, which would clear out the gas quickly, at least from the turret. The forward hull would not benefit from this draft and so suffered lethal concentrations.

A Lifebuoy flamethrower during a demonstration

A suggestion was made to just use the Lifebuoy flame thrower. However, Porton Down pointed out that the range of such a weapon would be just 18 yards, and the flow rate so slow that it would be difficult to reach a dangerous concentration. 

The Squirt itself could be adapted to be a flamethrower by fixing an ignition device onto the nozzle and filling the container with diesel. This would have made a pretty poor flame weapon, unless the fuel was thickened.

In the end Porton Down suggested that fifty charged Squirts should be produced and held against operational need at Porton Down. This was because it would take six months before the Squirts would begin rolling off the production line should they be suddenly needed. However, the documents do not say if this occurred.

Image credits:
www.jaegerplatoon.net and IndustrialTside