Leave him alone…

…and he'll play for hours.
BUT
I wish he wouldn't. 
       He was a. long way off and, while I've no doubt there is one, I can't find a speed limit for Talkin Tarn; but I doubt it's much faster, if any, than the Canal & River Trust who tell us:-
"On our network the speed limit on most canals is 4 miles per hour and on most rivers it's a bit higher at 6 miles per hour, but speed isn't the only factor you need to consider." etc.
       However, having, coincidentally, just seen a small Car on YouTube  circuiting a track at a scale-speed in excess of 200m.p.h. I think this wee thing was doing at least well over 100 m.p.h.