The Holman Projector was the wartime equivalent of a T-shirt cannon: a pneumatic mortar powered by compressed air or high-pressure steam. About 4,500 were built across three marks, and the later version could launch multiple projectiles semi-automatically to roughly 1,000 feet. Crews also used it to fire potatoes. It suited trawlers, coastal motor boats, and merchant vessels that lacked fittings for conventional anti-aircraft weapons. The projector did not account for many aircraft losses, but a sudden barrage could deter or disrupt a low-level attack. Developed in Camborne, Cornwall and tested nearby, it also has a distinct local industrial history. Its narrow small-vessel role was easier to improve than grander aerial-minefield schemes.
Chapter · 56:52-1:00:46
The Holman Projector gave small craft an improvised deterrent
The Holman Projector was a rapidly produced pneumatic mortar that gave small vessels a deterrent against low-flying attackers.