Been searching/reading awhile haven’t found answer to this: is there a specific difference in rocker between “fins forward” kneeboard and “fins rearward (?)” or is it just normal rocker “rules” and move the fins around for different ride?
Many thanks
Have you tried http://www.rodndtube.com ?
Since you don’t have legs for pumping, unweighting, and absorption, most knee riders use a flatter tail rocker for speed.
Also, the game is tube riding, so flatter tail rocker can come out more often.
Tail kick almost doesn’t sense, as speed is the game, not vert moves.
Thin boards with flat rocker.
Yes. Have a Blast Hawaii board. Called fins forward design and they are quite a bit further forward than say a typical stand up board though not as far forward as some Aussie boards. Then there are kneeboards that have fins closer to tail more like typical stand up. I know there is lot of variation in amount of rocker between various knee designs but how about distribution. I don’t think all are totally flat in tail like classic fish. Mine for instance has a small amount of lift in tail (it is designed for small to medium waves).
I used to ride stand up eggswith long single fin box and move fin forward and back for different conditions or how I wanted to ride. Obviously, different fin positions same rocker. I’'m wondering if this is the case with the two schools of KB design, just where fins are place, or is there more to it than that as a rule?
Been searching/reading awhile haven’t found answer to this: is there a specific difference in rocker between “fins forward” kneeboard and “fins rearward (?)” or is it just normal rocker “rules” and move the fins around for different ride?
Many thanks
I emailed this question to a long time close friend in another forum
(KSUSA):
Hal,
I can discuss the differences as I have found examples
of them in Nature.
Essentially Australian design and shapes have evolved with
the ‘fin(s) forward’ concept since the early 70’s with Peter Crawford and the Single Fin Slab , I’m not
sure of the rockers on these boards but I assume they
were essentially of little rocker, had a single fin shunted
very forward, and had a wide and full outline throughout
with this combination and every variable tending toward
full on loose…I would have to properly guess that they
were using very little rocker on these boards as a way
to stiffen em’ up a bit and that is a safe guess since
I know the board lengths of these corresponded to
US Kneeboard lengths at that time 5’2" -5’6"-5’8"
being very common, depending on weight and intended
surf size.
That was the past.
Currently Australian kneeboards employ several design factors.
One: the fin placement is far forward of where a standup board
has it. This placement moves the pivot point closer to a kneeboarders kneecap area and behind where most of his
turning and pivotiing is occuring …this is a good thing.
Two: To offset this wildly loose fin placement , you have to have
the rails more foiled to provide hold when needed as the fins
are not providing as much hold as with a more rearward position.
Adding boad length adds more rail and consequently more hold.
Three: But with added length we add liberal rocker and use concaves to flatten the rocker…
so the board turns like it has alot of rocker but has speed like a flatter rocker.
Now as to US Kneeboards, they evolved from the Lis Fish
(Twin Fin Fish) toward Quad finned boards that essentially
have ranged from the same 5’2" -5’6" -5’8" sizes that were
present in Australia boards in the 70’s and 80’s.
A Graphic comparsion is that Australian kneeboards have
their fins far forward but the US Kneeboards have the same
or near the same placement as a Simon Anderson thruster
with the fin clusters set very near the end of the tail.
The US kneeboards have very little rocker.
Currently US KNeeboards still range in the 5’4"-5’8" range
with litte rocker and fins tacked onto the tail.
As to a specific of your question I havent seen any US Kneeboards with fins tacked on the tail with larger length and ‘banana’ rocker and concave,
unless of course that board was a specialty big wave board.
Perhaps a good kneeboard could be made with fins tacked
on the tail incorporating all the other Australian design elements, but with this design(US) its always been felt and practiced that
as board length went higher you strictly were building a board
for bigger waves.
With the Australian designs and the variables at play it is rather
practical to make a uncharacteristically large kneeboard
( 5’10 - 6’5" and sometimes longer)
and have it specifically tuned for either large or small surf.
US designs with fins tacked on the tail have never demonstrated this design versatility.
Could a US design with fins tacked on the tail be as versatile
as a design… Anything is possible , but no one has demonstrated
or put the work into demonstrating this, that I know of.
Bee.
Thank you Hal. That’s just the kind of detailed info I was hoping for!