During the winter of 1940, the Admiralty called for a weapon that could be mounted at the mouths of rivers to engage approaching landing craft or seaplanes, to be ready for the following spring. A simple weapon that could be mass-produced at a time of steel shortages was required, and the task was given to Lieutenant-Commander Norway of the Department of Miscellaneous Weapon Development, part of the Admiralty.
The solution was a simple rocket weapon – known as ‘Radiator’. It fired salvos of ten 2-inch rockets horizontally (on a fixed or pivoted chassis, the latter giving an arc of 90˚) and did not have to be elevated or trained. They had a range of 2,000 yards and the length of the beaten zone was approx 1,000 yards. Radiators were mounted in pairs and required a party of one NCO and six men. The inaccuracy of individual rockets was a characteristic that was useful for such a system – as it gave a good spread of shots. The weapon system underwent trials at a stretch of water, west of Aldeburgh, Suffolk.
The team carrying out the trials were Lieutenant Tolman and Lieutenant-Commander Brinsmead and the account in Gerald Pawle’s book, ‘The Secret War 1939-45’ is worth quoting in detail:
“When they arrived and unpacked their gear they found they had not brought a firing switch with them, so an ordinary cheap tumbler switch was brought at a shop in the nearest village. Rocket weapons have one particularly unpleasant trait; at the moment of firing a searing tongue of flame belches from the rear of the mounting. Mindful of this, Tolman and Brinsmead followed a set safety routine, and two switches – a safety switch and firing switch – had to be brought into operation before each salvo was loosed off across the marshes.
When the Radiator was wired up they fired several rounds successfully, and they were both standing behind the rocket gun, when Brinsmead said, “Let’s try one more salvo, and then pack up”. He flicked over the safety switch, and Tolman had just started to walk across to operate the firing switch when there was a tremendous explosion. The tumbler switch had short-circuited, everything was enveloped in flame, and Brinsmead, standing right in the path of the blast, was instantly scorched brown from head to foot. Several discs of thick millboard from the base of the rockets struck Tolman, hurling him flat on his face, but he got off lightly, his only substantial wound being caused by a most unlikely projectile – a spirit-level, which the blast had swept from a bench at the rear of the mounting. The arrival back at the Admiralty of the Radiator trial team caused quite a stir, for the unfortunate Brinsmead had lost his eyebrows, his eyelashes and most of his hair – and was deaf for several weeks afterwards. It was a salutary lesson in safety precautions!”
Above: Left - plan of trial site, west of Aldeburgh. Middle and right - the firing / observation post.
Above: Left - the firing / observation post and a rocket locker. Middle - platform for Radiator rocket. Right - mount for the Radiator rocket. Presumably, given the infrastructure present on this site, the trial site became part of the operational Radiator defences.
The Radiator passed its trials with no further mishaps and many of these anti-invasion rocket guns were installed on the East Coast. In Suffolk at least three Radiator sites were installed – one on the River Stour, one on the Orwell and one on the Deben. The Deben and Stour sites were manned by 6th Battalion Suffolk Home Guard.
Above: 2" Radiator sites in Suffolk
Above: Left - plan of the River Orwell Radiator site.
Middle and right - the firing / observation post.
Above: Lef and middle - the two firing posts, River Orwell Radiator site. Right - the filed of fire over the Orwell.
The Secret War 1939-45, G Pawle, The Companion Book Club, 1958