20 interesting statemente re quad v tri

[Steeno]

is that unweight or unload

[Beeline2.0]

..

[hart]

Beeline,

For me, you not only struck it on the head mate..you drove it home.

The nail, that is.

I have never come across the expression "unweighting" until I started reading from this site..which on my part, isn't really saying anything..but,

"Purposeful unweighting" is what this is about..or in fact, what it isnt.

Apart from a distribution of weight from either one rail to the other..or maybe from your rail back to the bottom..and then back again..I can't see any purpose in trying to unweight riding a kneeboard. Unweighting isn't a 'manoeuvre', it is the means toward one.

Even a foam climb can be made at speed..if you hit it square enough.

And then of course..not catch.



hart

[john -]

i think unweight is a term for describing the opposite of low and driving when low and driving is not a constant - unweighting for some might be a speed producing move that does not entail low and drive - move/position in need of redefinition - work on a new word perhaps

dorje


4 hours later after a nap and consultation with my semantic advisor

HIGH PROPULSION as a means of speed generation in a situation where speed can be lost due to loss of contact with the essence (wave face). On reconnection with wave face, stance is relaxed slightly to allow for pivots/twists/bum shifts/shoulder transferance and farts to manouvre craft

[DrStrange]

a board which has mass which displaces water,means it's buoyant.

Point of order--buoyancy from volume not mass; massive ocean liner floats (big volume vs mass) tiny pebble sinks like, well a rock (small vol vs mass)

Pressure from body weight forces the board down.When the body lifts,the board responds by popping up due to release of body weight.When board meets body it stops,board and body resume the same state of flotation as before the move

Proly about right.

Unweighting isn't a 'manoeuvre', it is the means toward one

This is great! Unweighting is what happens automatically as you release pressure on rail and transition to pressuring other rail (for example).

[K-man]

Mornin to ya all.

Doc made a point about this unweighting thing.Didn't quite get it till I experimented kneeling on the floor to test his theory The old dog was right,you can unweight without exerting an initial force.By using the upper torso it/s possible to lift off a surface.While practicing this manuever my sweetie was rolling her eyes and making disparaging remarks about my mental health,and what in hell are ya doin Explained that it was a tantric move to eliminate the dreaded ''halitosis of the blow hole''She left laughing-thank god for good women
Does this hav any practical application for KBing,probably not.Then again nothing ventured,nothing gained.

K

[Beeline2.0]

..

[K-man]

beeline,

Zoundz like there's an agreement.''unloading''same ting no


hart-doc-
[Unweighting is what happens automatically.As you release pressure on rail and transition to pressuring other rail''
Got it But what happens when you release pressure on the rail and dont transition to the other rail ,but simply do the ''doc move''unweight-unload,slide straight up parallel to the wave,pop off[air] or opop the fins and slide down on upper third of the board[I've said this before]while humming the theme to the beverely hillbillies-or your favorite duran duran song Then pop in the fins-hopefully getting a tub Gotten tubed-working on the tubs

Clarification on the doc move-unload-unweight without exerting pressure-

I can do it the other way[pressure]and in certail situations such as low period swells peaks but not much wall, no where to go but up.Ain't blowing my horn,just trying to verbalise these ideas so others know what i'm saying

k

[DrStrange]

The old dog was right,you can unweight without exerting an initial force

Bwa-ha-ha-haaaaa. yet another example of senior treachery...

[Beeline2.0]

..

[Bryan Jackson]

Regarding unweighting from a kneeling position. Sorry but that is just physically impossible. Don't believe me. Kneel down on the floor and try to pull your legs up underneath you, momentarily losing contact with the floor. Although you can do this from a standing postion (as previously noted), it cannot be done from a kneeling postion, so it has absolutely no bearing whatsoever on KBing . (Warning: do not attempt this manuever in the presence of others as you will look rather foolish! )

In addition, this discussion has totally ignored the importance of fin dynamics. This is a common but not insignificant mistake made by most surfers, both standup and KBers alike .

Best example: Greenough style single fin.

When board is placed in a turn, especially a hard bottom turn, fin flexes (like a spring) and energy is stored in fin. When board is released from turn, stored energy is transmitted back to board (thus board “springs out of turn”) .

Same thing going on with twins, tri fins, and quads, just not as dramatic. The fins are smaller and thus have less flex, and thus less energy to impart, but there is still definitely a certain amount of flex and energy release taking place. (An interesting physics experiment would be to compare a single fin, a tri fin and a quad set-up in a controlled laboratory setting and measure how much they differ by in this crucial factor.)

Toe-in (with multiple fin set-ups) also changes the board’s dynamics. For example, although toe-in creates a certain amount of drag (thus making the board slower) it also makes the board easier to turn (and thus much more fun to ride ).

Think of the ailerons on an airplane’s wing (the moveable trailing edges). When you raise the trailing edge the airflow is redirected and the wing will change pitch, turning in a direction opposite to the direction the aileron is now pointed (for example, if the aileron is pointed downwards, the wing will turn upwards).

Now think of the board and attached fins as a sort of airplane wing. Consider the tri fin, for example, since that is the simplest situation (although the same principle applies to the quad or any other multiple fin set-up for that matter).

The side fins, if toed-in, are in a permanent state of redirecting the waterflow away from the centerline of the board. If it weren’t for the presence of the center fin and/or the opposing side fin, the board would constantly turn in the direction the side fin is pointed away from. That is, if it had only one toed-in side fin, instead of going straight the board would want to constantly run in circles .

The rider changes the water flow across the bottom of the board by, for example, leaning into a turn, applying different amounts of pressure to one side or the other, etc., and takes advantage of the board's natural tendency to turn in that direction. He or she changes the dynamics of the fin forces normally acting in balance to keep the board running in a straight line .

Good example: pop the outside fin out of the water on a hard bottom turn and now you have temporarily entirely removed it as a balancing force (i.e., it is no longer acting in opposition to the side fin still in the water). All you are now working with is the center fin and the one remaining side fin still in the water, and the board thus wants to turn up the face of the wave . (Of course, put too much pressure/weight on the inside rail of the board and the fins can no longer hold. Result: board spins out which is, of course, a very bad thing! ).

Now consider what would happen if all three fins were aligned perfectly parallel. Yes the board would be faster (less drag) but since all three fins are tracking in a straight line no matter what dynamics are applied to the board (pressure on the rails, leaning into a turn, etc.) it would always want to run in a straight line and would of course, be much harder to turn and maneuver .

Check out Bud’s remarks regarding his Fish with keel fins. Normally keel fins are set parallel. Bud toed-in the keel fins on his Fish by two degrees to make the board “easier to turn”.

(Of course, this discussion has focused entirely on fin dynamics and ignored all other aspects of board design which are also important in the dynamics of turning and maneuvering. Even so, I think that anyone can see just how critical a consideration of fin design and dynamics is.)

[john -]

the definition of unweighting is still seemingly subjective

it can at times seem to mean transferance of said mass - front to back, side to side

on a steep drop when one is in freefall - the attempt to lift body weight off the board - then bring it back onto the board for the bottom turn

as i said in another post - lately ive discovered raising my body higher when caught behind the wash has given me the speed to get around the wash - not pushing down

or we can.....

wait for Headwax to chime in again - as it was his term (???) and he can continue to enlighten us or confuse or .........







parent teacher night - please keep me sanely entertained inbetween the blah

[willli]

This fin flex thing and the twang mythology of acceleration doesn't fit.
The fin area involved and the distance of the snap wouldn't even be noticed in a power sense, yet this concept has been sold since the sixties and surfers continue to repeat it like gospel. Its akin to saying that the flexed wings of a plane coming out of a hard bank regain their original shape and that motion serves to beat the plane upward like the wing of a bird. can you hear the aero engineers laughing? I think flex in a long gg fin is actually twist in response to flow forces. Breaking this area down and spreading it out (multi-fins) each piece adding to the overall effort, effectively increase the fin base (6'' to about 12") which means a dramatic increase in power and less overall drag. The benefit of fin flex lies in its response to flow forces, it doesn't stall and create pockets of "dirty" water (to borrow from sailing); rather it responds to the forces placed on it and tends to remain clean flowing, just like the airplane wing. Wouldn't it be nice to have computers design our fin foils instead of relying on sandpaper and intuition?

[surfhorn]

Just a quick note re: unweighting. I've used the manuever of hopping my board, much like standups do in flat sections.

Push downward on the board and hop.......for every action there is an opposite and equal reaction, or something to that efffect.

Mostly I used this move just before I hit another surfer...........I would hop my board so it would ride up and over the other person. I was also able to sink my 12" fin almost all the way through the rail to the guy's stringer.