German Screw Drive tractor

[Snowy]

Very interesting indeed, but the Archimedean screw vehicle was not unknown to the Allies during the war. Post-war the most well-known ASV was the Chrysler Marsh Screw Amphibian which was prototyped in the mid-late 60's for potential use in Vietnam.

Here is a frame grab from the OSS film on the T-15 Weasel, from the fabulous RealMilitaryFlix website showing an ASV being trialled in the USA. It looks like a converted tractor. Given that this design was trialled and found wanting (as part of Operation Plough, which lead to the development of the Weasel itself) I would hazard a guess as to it being 1942 perhaps.



References:
http://www.realmilitaryflix.com/public/441.cfm?sd=61
http://en.wikipedia.org/wiki/Geoffre...eration_Plough

Steve.