Another loss of thrust control sea story: I saw a video where a modern tractor tug (I assume it was ASD,) was escorting a ship out of the channel at the end of a very long lead on the bow. Something happened, and tug started to spin in place with as much force as it possessed, causing it to wind up its line around the wheelhouse glass. It made almost two complete turns before contact with the stacks burned through the line. The operator could have been badly injured or killed, and my takeaway was to always know where your e-stops are and plan to use them. Never heard what caused the malfunction.