Padang July 2016 (image heavy)

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Cranked
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Re: Padang July 2016 (image heavy)

Post by Cranked » Wed Aug 10, 2016 4:16 pm

What is really of concern here and of undoubted interest to the surfing public at large is, "What is Michel Houellebecq's stance on surftechs?"
“I don’t necessarily agree with everything I say ”— Marshall McLuhan

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Re: Padang July 2016 (image heavy)

Post by Hatchnam » Wed Aug 10, 2016 5:28 pm

Cranked wrote:What is really of concern here and of undoubted interest to the surfing public at large is, "What is Michel Houellebecq's stance on surftechs?"
What about epoxy popout mini mals from china. What would Michel Houellebecq have to say about that ?

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Re: Padang July 2016 (image heavy)

Post by steve shearer » Wed Aug 10, 2016 6:20 pm

Cranked wrote:[quote="foamy" To my mind it seems it would be better to weight the back foot because that's where the board is more narrow and there might even be some V,
Umm. nope.
It's the entry curve and majority of surface area, which is under the front foot, which is the problem. As hydrostatic forces transition to hydrodynamic forces the laminar flow turns to turbulent flow within the first few inches.
Coupled with the very high modulus of elasticity(stiffness) of the surftechs and you get that horrible chattery, out of control feeling which manifests at speed or with bump.
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Cranked
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Re: Padang July 2016 (image heavy)

Post by Cranked » Wed Aug 10, 2016 6:48 pm

Sounds like there is some a pretty exacting testing supporting your statement. Can you give some references that describe the test regimes used and also I assume they would quantify the profile of the effect for varying moduli of elasticity.
“I don’t necessarily agree with everything I say ”— Marshall McLuhan

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Re: Padang July 2016 (image heavy)

Post by steve shearer » Wed Aug 10, 2016 7:21 pm

Basic hydrodynamics, you can look it up very easily. Most universities have open online courses you can access.

Swaylocks has some very good references on the stiffness of various construction techniques including surftechs and how that effects hydrodynamic flow.

But I think most would agree (even you) they are stiffer than poly's.

It's that dampening effect of poly's, with it's lower modulus of elasticity, which smooths subjective feeling of the turbulent flow across the wetted area, especially at speed and provides that very consistent sense of reliable handling which maintains the dominance of PU/PE as a construction technique.

Of course, in small weak, clean and low energy waves the stiffer Surftechs provide a better transfer of energy. Braithy and Iggs pointed that out very well.
I want Nightclub Dwight dead in his grave I want the nice-nice up in blazes

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Cranked
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Re: Padang July 2016 (image heavy)

Post by Cranked » Wed Aug 10, 2016 8:11 pm

So you are saying that your conclusions have been drawn from hydrodynamics studies and theory in general? I don't I think general principles would be sufficient to support your conclusions.

We do need to know how the effect varies with the modulus of elasticity as the effect may be negligible for the difference in the modulus of elasticity for a poly as compared to a sandwich construction. Remember, you can't site personal feel here as you've elected to go to theory and, presumably, controlled testing to back your argument.

There are a lot of other factors besides modulus of elasticity that would influence the behaviour.

A board with narrow, pointed, upturned nose that extends for a few feet and has lots of rolled V and is very thin (flexible) would perform quite differently in chop than one that doesn't have these attributes (by-the-way, this describes most of my ST boards). In addition the board is not flat in the water, just the rail and a small part of the hull is engaged, so we have to look at the rail profile as well and its impact. A flat or concave hull would also be effected more than a board with roll and/or V.

If you can't quantify (and control during testing) the effect of all these variables, against the effect of varying moduli of elasticity then you can't draw any conclusions from the theory as the modulus of elasticity as a factor may be outweighed by the cumulative effect of the other factors that I mentioned.

I agree with the premise that a stiffer and/or lighter board would tend to not handle chop as well as a heavier, more flexible board; but the effect of a myriad of other design factors and the lack of any quantification of any of those factors, means that the premise cannot be quantified for a given board construction and design and we are back to subjective assessment as the main determinant.
“I don’t necessarily agree with everything I say ”— Marshall McLuhan

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