Oliver Moffatt writes:

I had a useful lesson on Saturday. Coming off the trolley, I immediately climbed
above the tug, and continued to climb until the weak link broke when I was about
to release.

No amount of bring in the bar-to-the-knees while on tow made any difference, and
I had no idea what was wrong.

Flying back to land I found that the VG was fully slack. Viewing the video later
it showed that the rope had bounced out of the cleat less than five seconds
after I started rolling.

I had previously understood that aerotowing with a slack VG would simply make it
very hard to pull in to increase my speed. In fact, pulling in wasn't difficult.
The problem was that even at full speed I was still climbing much faster than
the tug.

Lesson learned, and I spent an hour on Sunday reaming out the hole in my wheel
hub as the small hole was not well aligned with the VG jamming cleat, so that
the cleat did not have a firm grip on the VG rope.