Some might like to see these , from Mark Rabbidge
and Tim Bessell
He calls it the ‘vector channel bottom’.
They’re both veteran shapers -Anyone ridden either design and care to comment / discuss ?
Just for reference, here are links to a couple of boards I've posted. George Greenough was doing this sort of rail slot/edge on his kneeboards way back when. Wilderness apparently has the OK to continue. These two were shaped by Bob Duncan.
Huckleberry,
That “bonzer” looks awesome very functional.
Epic looking boards JM!
The rails on those are ‘stepped’ whereas Rabbidge’s seem to be more 'notches '.Presumably the intentionis that they claw into the water and propel you forward.
I can see now that’s the idea behind the side channels on the Bonzer Light Vehicle too.
If I squint at that pic of the Rabbidge fish I can imagine some Frye/Larmo winglets on the tail extending on the same line as the notch channels, that’d be trippy.
What about the Bessell channels, what’s the theory there ?They must have an effect that justifies the extra work.
A vid of him shaping 'em -
wow, that guy moves fast! Title of the video should be: why a shaper deserves his pay!
I like the Rabbidge rail channel but I wonder if it wouldn’t create less water disruption/drag if it were on the deck side. I can’t recall the names but I have seen several Aussie shapers employ that one on the deck side where the benefit is a thinner rail but the overall shape retains more foam for float.
You cannot discern from the picture but maybe Rabbidges’ rail channel doesn’t follow the bottom rocker. Perhaps it is a flatter, more efficient rocker? Maybe that is the gain in speed as he says.
I too have difficulty seeing how Bessell’s bottom provides benefit. I not familiar with any scenario where water would be inclined to follow such a steep arc with efficiency. Im assuming his intention is some sort of venturi effect but it could be otherwise- maybe he intends to disrupt water flow? In any case, the fact that my peabrain may not comprehend the concept does not diminish its possible validity!
He (Bessell) has some interesting techniques, especially the way he uses his planer from one side of the board.