[hpv-boats] Pivoting prop

[dennis]

Ian
 
David Witt has several published articles on his boats.These can be found under David Witt pedal boats in google. 
The pivoting prop is not really a universal joint and is not very well described but can be found in his article published by Human Power  44V 13n1 1997.
This can be found at BHPC.org Human Power Journals.
It is simply a slot and a pivot so that the prop can find its own vertical position. I would have thought that a 6 to 8 mm pin would be strong enough for the prop to pivot on but a collar should be used to prevent the prop falling off if the pin broke as did your u-joints.

Dennis