This is Prince Helfrich, a pioneering river runner, leading an expedition down the Owyhee River in the mid-sixties.
My thanks to reader John Ost of Portland, Oregon, for the tip-off. John tells me he has made the same trip with his wife and friends in his drift boat several times – he does it as the river is dropping and is clearer than it was when this film was made.
Here are some British people having some remarkably innocent fun on the Thames in 1951. I wonder whether they could be persuaded to do this today? Perhaps I should try singing it somewhere… perhaps at New Year’s Eve.
My thanks to Intheboatshed regular Paul Mullings for the link.
The song is actually a bona fide sea song that bears the title Sons of the Sea, according to the Wikipedia.
There’s another snippet of the same silly entertainment in a Huggets series film from the same period.