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Staged vs continuous rocker.
- Thread starter casa_mugrienta
- Start date
Big flat spot no worky for everyone.
Stable platform but sensitivity is reduced.
Good for guys who like to use blunt force trauma on a wave......maybe not so much for those that rely more on timing and placement.
Stable platform but sensitivity is reduced.
Good for guys who like to use blunt force trauma on a wave......maybe not so much for those that rely more on timing and placement.
Reducing the apex reduces the lift in that area .
Entry angle on my boards reduces as it nears the center to none - the the exit begins ! ;-)
The terms are thrown around to the point where they verge on being mostly subjective.
Why is there an apex where entry changes to release ?
Why would want to reduce that release ?
Too much Apex ? Corrected by an additional "Feature" ?
Why would want to reduce that release ?
Too much Apex ? Corrected by an additional "Feature" ?
For HPSB
“Staged” rocker (flat section somewhere in the middle) - single to double concave.
”Continuous“ rocker - Single all the way, single to flat, single to flat to vee (for quads)
“Staged” rocker (flat section somewhere in the middle) - single to double concave.
”Continuous“ rocker - Single all the way, single to flat, single to flat to vee (for quads)
I'm always a little skeptical of the use of the word "lift." I remember Roy calling out Daniel Thompson for his use of aero/hydrodnamic terms. I actually thought Roy was right in that instance.
This is how I understand lift-
Good old Bernoulli. But this assumes a pressure differential between a top and bottom surface, a condition that does not exist with a surfboard bottom. And even assuming that a single surface produces lift, wouldn't a surfboard's rocker be like this?
So the lift is pushing the board down into the wave?
And this- "Reducing the apex reduces the lift in that area "- defies the well known anecdotal evidence that boards with less rocker are faster than an otherwise identical board with more rocker.
That said, I do prefer a continuous rocker. My favorite blanks are the EAs. (Arakawa?). This is the blank I'm working with right now. I think it is pretty continuous-
And even if I don't necessarily buy whatever hydrodynamica mumbo jumbo a shaper purports to manipulate, it doesn't mean I think their boards don't work. I know Tomo's and Greg's work from the anecdotal evidence. I'm not picking a fight with you , GG, but feel free to explain your statement or tear apart mine.
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I agree with all your physics llilibel. Bernoulli can't be applied because there is no top lifting surface on a planing vessel. Yes where water forms laminar flow across a convex rocker (taking into account diagonal flow) then there will be downward suction. Higher rocker => greater suction and less lift. The "apex" or bend or whatever we want to call it where the two stages of plane meet will be a source of increased suction.
My attempts to try and understand why our surfboards do not head towards the bottom of the sea has led me to believe the following things:
The water is not laminar everywhere - there is a massive ridge of high pressure called "the spray root" i.e entry point of the hull which starts at the nose scoop and forms approximately a diagonal line down the board.
Water curving outwards towards the rail can encounter a flat or even convex path (illustrated by the MC trick of placing a straight edge diagonally across high rockered/high concaved boards).
Also as soon as we step on the tail of high tail rocker/staged section any suction gets replaced by lift when the angle of attack increases and Newton's third law says that the deflection from the increased angle of attack will cause lift.
My attempts to try and understand why our surfboards do not head towards the bottom of the sea has led me to believe the following things:
The water is not laminar everywhere - there is a massive ridge of high pressure called "the spray root" i.e entry point of the hull which starts at the nose scoop and forms approximately a diagonal line down the board.
Water curving outwards towards the rail can encounter a flat or even convex path (illustrated by the MC trick of placing a straight edge diagonally across high rockered/high concaved boards).
Also as soon as we step on the tail of high tail rocker/staged section any suction gets replaced by lift when the angle of attack increases and Newton's third law says that the deflection from the increased angle of attack will cause lift.
I have little to no understanding of this with surfboards but I have experience with wakeboards. I liked three stage rocker on wakeboards cause I rode steeper wakes and it translated to my riding style better. continuous rocker seemed to be better suited for mellower transition of boat wakes (manufacturer speciifc).
Just rambling thoughts in my head but I wonder if I would like a staged rocker in steep waves a continuous in mellow point style waves?
i'm embarrassed to say I don't know what kind of rocker any of my boards have in this regard
Just rambling thoughts in my head but I wonder if I would like a staged rocker in steep waves a continuous in mellow point style waves?
i'm embarrassed to say I don't know what kind of rocker any of my boards have in this regard
Entry angle helps create initial lift up to plane - angle hand upward out car window to experience this ;-) - No foil involved
Tail rocker controls that planing effect and release of planing pressures , still entry and exit angles all thru the back half depending on the angle the board is riding on .
Tail rocker controls that planing effect and release of planing pressures , still entry and exit angles all thru the back half depending on the angle the board is riding on .
Thanks for the clarification. I guess I would have called that "planing" rather than lift , but a quick google says it is lift.
But now your apex term is confusing me. Is that where you perceive the rocker changes more drastically? Would staged rocker have two apexes? Also doesn't rocker apex change position depending on where you're standing on the board, like Mr. J mentioned above? Would you call your rocker continuous or staged?
In pedagogical terms, you need to create some "scaffolding" for us slow learners...