R=Rough terrain , 13 = the deck height in meters at full reach , S= Snorkel (his brand) and 1 being its position in the fleet . (among other 13mtr machines)
Amazing bit of kit , the photo wont give a good impression of the actual size ..... i was thinking of taking him out to the airport on a good norwest day , and snapping from 13 meters up on the approach to 029

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