Hi Chris,
You means these pics - probably mid 80s
http://www.ukriversguidebook.co.uk/rivers/england/south-west/photos/river-webburnYes that was earlier in the 80's when the Webburn was NOT a tree strewn ditch, only about 2-3 portages and it made a great trip. Sadly a few storms in later years destroyed the pleasure. The guy in the white cag, Greg Preston, went home after one trip on the moor to tell his family what he had been doing, and his uncle regaled him with stories about how he had been a Royal Marine Commando in the war, and had done a trip down the upper Dart for their "Cockleshell Hero" type training.
Back in the 70s and 80s there was a strong kayaking group based at the Royal Navy Engineering College at Manadon, Plymouth. Four years in Plymouth, full Navy Officer salary, a massive engineering workshop to build GRP canoes and trailers etc, and a budget for encouraging outdoor pursuits. Ideal conditions to develop kayaking. That group, with various hangers on and friends did a lot of the early exploration of Dartmoor, and indeed also early trip to the Swiss/Austrian Alps out near Landeck in the 70s. But it was only when small plastic boats were available from the mid 80s that real Dartmoor exploration opened up on the more obscure parts of the moor, by which time there were a lot of other boaters around doing some good stuff.
Talking about smaller boats, On my first run down the West Dart I was told off by Clive Waghorn, one of these older and bolder boaters, for daring to use a Dancer, which was inappropriate for the conditions being too short and too low a volume. Funny how attitudes change.
For the record, if it counts, I can recall descents of:
the Webburn with a Navy group about 85.
West Dart (from Two Bridges) with a Navy group about 85. (The bit from Hexworthy to Dartmeet is almost as good as anything on the Upper, and Hexworthy used to be our standard start point for an Upper run until access issues and spawning became a problem.)
East Dart (solo) 86
Erme (with Steve England) 2nd Oct 1987
Plym (Solo, but low water) some time in 88 or early 89.
Whether these are first descents I don't really know or care, I enjoyed them at the time and that's what counts. But I am happy to mention them here to fill in the early history of the area.
Simon