Dave" wrote

I figure it must have been slowing us by at least half a knot.

From the perspective of one who occasionally has to consider speed and
resistance of boats professionally, I really doubt that the dinghy is
costing you half a knot, at least not on the 32 foot size boats
considered in this thread. I've also pulled them in on long painters
and then let them go to see of the speed bumps up. Not that I've ever
been able to detect before the rope runs out anyway. I admit though,
I still can't get it out of my head that we are going slower

--

Roger Long