It seems whatever style extension you choose will need some flex to it to absorb shock.. With the tiller cross bar turning as you raise and lower the rudders your yoke for attachment to the tiller cross bar will at some point bind. I fumbled my tiller over the back today during a tack and about the time the end hit the water the yoke cought and torked. Granted it wasn't much but the flex in the extension absorbed most of it. I think a stiff heavy extension might eventually damage the cross bar.
Fleet 119-Lake Erie's Finest