Half a tree
An 8m class yacht (12 odd tones if my memory serves me right) following the demise of the wind one afternoon.
A 50m towrope from which were hanging about 8,000 Optimist dinghies, (along with a few clinging to the grablines as well) again folowing the demise of the wind.... Does that count as one tow or the most number of things towed at once?
...ugliest thing you've towed on water?
Hmmm I'd thave to think about that one.