Interesting machine.
The US tested similar vehicles. In 1964 Chrysler developed the Marsh Screw. My 1972 copy of The Observer's Military Vehicle Directory gives speeds of 20mph in snow, 9.5 on water and 14 on "muck". It apparently could only manage a dismal 1.6 mph on sand!
I actually saw one of these when I was a kid, it was used for various tasks in the Shannon estuary. Seemed quite effective in that environment.
A bigger vehicle tested by Chrysler in 1969 for use in Vietnam was the RUC (Riverine Utility Craft). Bigger and faster, 15.7 knots on water, 25 mph on marsh, but only 3.5 mph on land.
Cheers
Pics 1&2 are Marsh Screw, pic 3 is RUC