OK. So I just watched Force 10 From Navarone…again.
Did the British Army really have explosives that looked like dog droppings and exploded on contact?
And…were dams in Eastern Europe constructed so that “three small cases” of explosive could fatally breech them?
The Royal Air Force formed a special unit of Avro Lancasters and used a newly-developed “skip bomb” in an attack on three German dams in WW2.
http://www.computing.dundee.ac.uk/staff/irmurray/bigbounc.asp#grandslam
Quite a bit of information here about Barnes Wallis’ dam busters and earthquake bombs.
Dog droppings, I don’t know about. But Leo Marks was a cryptographer for Churchill’s Special Operations Executive (SOE), and he describes in his book “Between Silk and Cyanide”, explosive devices made to look like piles of camel droppings. The idea was to leave them on roads in the North Africa campaign, on the theory that bored enemy drivers would swerve to deliberately run them over and blow a wheel off or worse. Later versions came with tire tread marks already running through the pile!
The detonation method for these camel turd bombs wasn’t described, so I don’t know if they used a contact-sensitive explosive or incorporated a mechanical or electrical fuze, e.g. a trembler switch or a modified anti-personnel mine trigger. I would suspect the latter, since transporting sensitive explosives adds an unecessary hazard to an already hazardous pasttime…
Generally no - they were massive and bomb-hardened, and three small cases of explosive were unlikely to achieve anything, at least from the outside. If I’m thinking of the same movie though, the explosives were taken within the dam, which typically contain inlet channels, turbines and tailrace channels. It’s barely feasible that a small quantity of explosives within a dam in the right place might cause its collapse, but I still suspect that was largely cinematic license.
The explosives on the road were a gooey mass and the instructions were to drop them on the road randomly. There were no detonators inserted in the droppings, and they exploded when run over by trucks.
The explosives in the dam were indeed placed inside, and the only clue to their location is that the men placing them were shown travelling down several lengths of stairs, the last a series of concrete steps that led to a service tunnel in the concrete. The charges were placed presumably in the center of the dam, below the water as the ensuing breech was shown to be caused by the pressure of the water behind the dam finding a foothold in the cracks in the structure.
Bob Yunnie, in Warriors On Wheels, referred to ‘Turds, Calabrian’ - road mines disguised as animal dung.
But that Force Ten is a crappy film …