At 16:49 07 February 2015, GM wrote:
So is there no facility to release the rope at the tow plane end?

Bruce - as far as I can remember, the original Tost set-up had a
guillotine
built in, which allowed the tow pilot to 'release' the line from his end,
if needed.

Uli

Uli is correct. there is a guillotine at the end of the towplane. Doug