Mid 1950's, elementary school gym class on Friday was "Health Film" day. No better end to a week than this film. We loved it!
When Nick tumbles over the cliff we'd all scream; lights go on, projector gets clicked off and the teacher yells at us for our rowdy behavior and makes us sit stone quiet for the rest of the hour. This must've happened a half dozen times a semester. It was the same exact scenario in my brother's class and the neighbor girl's class, too. I guess every class. Some bizarre Friday ritual? Seeing this on Prelinger archives a few years back, was the 25th time I saw this movie, but the first time I ever actually saw the last part after Nick's plunge. (Ironically within days of those outbursts, we were asking the teacher if she can get us that film again - and she frequently did.)
There were other juicy scenes - the kid pouring gasoline on the fire and the one tilting the boat. Pure kiddie entertainment.
Back then, we so often heard: "Hey! Cut that out! You wanna poke out an eye?" It was probably in the top 5 most frequent warnings belted out by parents. And around 70 yrs later I don't remember anybody ever getting an eye poked out (except the kid in this movie).
I read somewhere that the "Nick" character was a child stunt actor and actually did suffer a broken arm in that scene.