Author Topic: Flatwater rocker???  (Read 3692 times)

Henrik F

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Flatwater rocker???
« on: January 13, 2013, 09:07:53 AM »
New question. Again. If anyone knows stuff about the rockerline (is it called that?) on a 14' flatwaterboard, please let me know. I suppose there are a lot of variations but some indication?

Many thanks

Henrik F
crosswater.se

Dwight (DW)

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Re: Flatwater rocker???
« Reply #1 on: January 13, 2013, 10:56:54 AM »
2.88" tail
2.88" nose

Henrik F

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Re: Flatwater rocker???
« Reply #2 on: January 13, 2013, 12:01:17 PM »
2.88" tail
2.88" nose

Thanks! Do I start measuring from the balance point and slowly rise it 2.88" or should there be a completely flat section?

Henrik F
crosswater.se

Dwight (DW)

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Re: Flatwater rocker???
« Reply #3 on: January 13, 2013, 02:35:22 PM »
A single arc curve will be fastest

DurhamSUP

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Re: Flatwater rocker???
« Reply #4 on: January 13, 2013, 03:11:17 PM »
I like to go even less. 1.5 nose and 2.5 tail. Wide point of board a little back from center and distribution of the rocker curve to match the wide point of the board.  i.e. slightly steeper tail rocker and more gradual nose.

Henrik F

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Re: Flatwater rocker???
« Reply #5 on: January 13, 2013, 09:31:32 PM »
:) Thanks!

Henrik F
crosswater.se

DavidJohn

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Re: Flatwater rocker???
« Reply #6 on: January 13, 2013, 10:33:07 PM »
I'm thinking tail rocker is the most important end because a cutting nose can sit I bit deep but the tail should just kiss the water when standing on the board or maybe even lifting off the water slightly so when paddling the tail sits just right and this should give a clean release of water without rooster tailing or making a wake.

It would be interesting to measure one of the new Fanatic Falcons because they did a lot of testing in this area before releasing their new boards.. As would Naish with the new LE's.

DJ

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Re: Flatwater rocker???
« Reply #7 on: January 14, 2013, 02:46:45 AM »
If it's any help, I got some measurements from my 14' Dominator.  Ignoring the effect of the 1/4" deep "V" cross section of the hull near the middle of the board, the nose rocker is about 1.25" occuring gradually over 2 feet, plus another 0.5" of "rounding" immediately at the nose which I don't think of as rocker, but totaling about 1.75".  The tail rocker about 2.0" occuring gradually over 5 feet, with slightly increasing curvature very near the tail.  At 150 pounds, both nose and tail are just in the water for me.

The pros have a jig for rocker measurements. You can measure rocker, at least roughly, by putting the board on a level floor or wedging it up against a wall, and measuing along the rail.  Doing it that way, subtract from all figures the height of the rail at the middle, caused by any V or oval cross section of the hull.


Henrik F

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Re: Flatwater rocker???
« Reply #8 on: January 14, 2013, 03:00:23 AM »
Thanks for all the input.  :) :) :)
I will pass this on to the guy who is going to help me build the board. He is an expert on building windsurfingboards but he has never built a SUP. So as you see, we need this info badly. He is going to scan my Fanatic Fly Race flatwater and then we are going to alter it to suit the conditions that I usually paddle in. My weight and other stuff. It is going to be a 14' hollow carbon board with goretex vents, Anterior ventral SUP Fin and probably around 24-25" width.

Thanks once again!!!

Henrik F
crosswater.se

Pierre

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Re: Flatwater rocker???
« Reply #9 on: February 02, 2013, 12:00:07 AM »
that rocker depends on the shape of the board... if your tail is square then the best is to have the tail just touching the water; and the bow a little in.. so depends on board width and your weight; bloc coefficient of hull etc. for a 80 kg /180 lbs paddler and 26" /66 cm wide board that will be around 6 cm means 2"1/2 at tail and same fore...if bow is wave piercing style it  can be immersed so... best rocker is according to hull shape and immersed calculated volume.
if your hull is pin-shaped looking like kayak; rocker can be almost NIL....
relations weight/width/hull depth for a 14-footer. CB assumed 0.55.
Masse  Kg    50   60   70   80   90   100
SIZE m                     
1.50   breadth=   53.9   56.7   59.2   61.5   63.7   65.7
   depth=   4.5   5.2   5.8   6.4   6.9   7.5
1.60   breadth=   55.1   57.9   60.4   62.8   65.0   67.1
   depth=   4.5   5.1   5.7   6.3   6.8   7.3
1.70   breadth=   56.1   59.0   61.6   64.0   66.3   68.4
   depth=   4.4   5.0   5.6   6.1   6.7   7.2
1.80   breadth=   57.2   60.1   62.7   65.2   67.5   69.6
   depth=   4.3   4.9   5.5   6.0   6.5   7.1
1.90   breadth=   58.2   61.1   63.8   66.3   68.7   70.8
   depth=   4.2   4.8   5.4   5.9   6.4   6.9
2.00   breadth=   59.1   62.1   64.9   67.4   69.8   72.0
   depth=   4.2   4.7   5.3   5.8   6.3   6.8

\HF/- Hi-Fun Hydroworks / custom boards,BZH, since 1982  /  *Link Removed*

Henrik F

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Re: Flatwater rocker???
« Reply #10 on: February 02, 2013, 01:34:47 AM »
that rocker depends on the shape of the board... if your tail is square then the best is to have the tail just touching the water; and the bow a little in.. so depends on board width and your weight; bloc coefficient of hull etc. for a 80 kg /180 lbs paddler and 26" /66 cm wide board that will be around 6 cm means 2"1/2 at tail and same fore...if bow is wave piercing style it  can be immersed so... best rocker is according to hull shape and immersed calculated volume.
if your hull is pin-shaped looking like kayak; rocker can be almost NIL....
relations weight/width/hull depth for a 14-footer. CB assumed 0.55.
Masse  Kg    50   60   70   80   90   100
SIZE m                     
1.50   breadth=   53.9   56.7   59.2   61.5   63.7   65.7
   depth=   4.5   5.2   5.8   6.4   6.9   7.5
1.60   breadth=   55.1   57.9   60.4   62.8   65.0   67.1
   depth=   4.5   5.1   5.7   6.3   6.8   7.3
1.70   breadth=   56.1   59.0   61.6   64.0   66.3   68.4
   depth=   4.4   5.0   5.6   6.1   6.7   7.2
1.80   breadth=   57.2   60.1   62.7   65.2   67.5   69.6
   depth=   4.3   4.9   5.5   6.0   6.5   7.1
1.90   breadth=   58.2   61.1   63.8   66.3   68.7   70.8
   depth=   4.2   4.8   5.4   5.9   6.4   6.9
2.00   breadth=   59.1   62.1   64.9   67.4   69.8   72.0
   depth=   4.2   4.7   5.3   5.8   6.3   6.8



Thanks!!!!!!

Henrik F
crosswater.se

 


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