.
Hello Frank -
I have an old reel to reel film that shows The Duke on a 4-person paddleboard.
In this film, the man in the back is shown prone paddling but once they caught the wave, he stood up and the lady got on his shoulders. It is not very apparent but Duke is using a double bladed paddle with a tether connected from the shaft to the front of the board. It appears as if the board is a hollow plywood model. I suppose it could be argued that the 'board' is more of a boat, but I kind of like it anyway. My best guess is that this film is from the mid 30s.
My apologies for the poor image quality. I took a snapshot of the film in freeze-frame mode after pausing the projector.
Regards,
John Mellor
.