The Blanik L13 as made also had a fixed bungee hook - which really was just a hook of metal protruding out from the Belly near the front.
I'm told they were all ordered (in the UK) to be cut off as they were an obvious danger to some form of hang up occurring where the cable might manage to get snagged up on it.
I learnt on a Blanik L13 on the winch so have very many flights as both P2 and solo as P1. I loved flying it solo - more so than the K8.
I can also remember the equally many rocket launches in the K8 thanks to an over enthusiastic winch driver who had just launched a series of 2 seaters and was still on autopilot - where it did indeed seem more akin to a steam catapult launch off an a/c carrier deck.
The worst and indeed most memorable was one where the acceleration rate was so high that both my feet lifted off the rudder pedals. The wing handler later reported that he did not move an inch much less actually run with the wing - come the "all out" signal the wing was snatched out of his hands as the K8 accelerated away.