On Friday, July 3, 2015 at 6:01:02 PM UTC+3, Dan Marotta wrote:
There was an article in Soaring back in the 80s, I believe, which
discussed rope tension during tow.* It's not very much for a glass
glider (20 lb) and I wouldn't think more than 40 lb. or so for a
drag master (2-33).* There's no harm in releasing at that tension.*

On a cross-country tow, yes. Not when climbing at 700 fpm at 70 knots! Then you've got to add 1/10th of the glider weight from the climb to the 1/40th of the glider weight from the drag.

i.e. more like 100 lb tension than 20 lb (for a modern single seater with a bit of water)