Author Topic: Wing Board Tail Rocker - Thoughts  (Read 9804 times)

burchas

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Re: Wing Board Tail Rocker - Thoughts
« Reply #15 on: June 03, 2022, 08:45:44 AM »
Almost every foil on the market is designed for a mount point that is flat to the deck surface.  Tail rocker throws off those angles and adds an angle that the foil (generally) wasn't designed for.

Certain design elements addressed this issue:

- Dropped concave deck parallel to mount point.
- Center bottom channel parallel to the deck
- Both of the above combination
- The step bottom mount point shown on the new Starboard Take-off and some other designs.

With that in mind, same wing board design, one with tail rocker the other without. Pros Vs. Cons

As mentioned, some popular designs like the Armstrong, F-One and Bill's SIC Manta ;) wing boards have considerable amount of tail rocker.
It's a deliberate design choice that , in theory (I assume they tested it), should work well with all their foils offering.
« Last Edit: June 03, 2022, 09:00:20 AM by burchas »
in progress...

peterp

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Re: Wing Board Tail Rocker - Thoughts
« Reply #16 on: June 03, 2022, 09:27:18 AM »
Tail-rocker is a conundrum - to get up on foil your actually want a displacement design which is always more efficient with some rocker and once you are up on foil you want the slippery, skippery feel of a planing hull for touchdowns. I agree with Jondrums observations except that a flat rocker board launches quicker when winging - that I find only potentially true on shorter sub 5'0ft wing boards. On longer wingboards the same trouble Jondrum describes becomes apparent - especially if you are trying to pump board up.

Kalama's board have zero rocker from what I can see along the centerline from the middle back - he solves the conumdrum with his extreme V in the tail which gives plenty rocker along the outline.

My take is that you need some rocker, especially on SUP's and the reason people think flat rockers work on wing boards is because the power on hand allows you to overcome the initial tail drag apparent when you try and pump up - once you overcome this drag (with the help of the wing) the board releases quickly and pops up on foil - it feels efficient, but it actually isn't.

Wave Chaser

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Re: Wing Board Tail Rocker - Thoughts
« Reply #17 on: June 03, 2022, 11:04:03 AM »
The 2022 Axis Froth 45L (4'4" X 23") has tail rocker.  The tracks are way back compared to most boards: 3" from the tail of the board.  When I place a straight edge on the tracks, it has about 5mm of tail kick and 1.5cm of tail rocker measured at the mid point of the board.  I do prefer the way it rides compared to a board with zero tail rocker (This is on Axis carbon 86cm mast and HPS 830).  The ride angle is more comfortable (it's not nose down).  Easier to recover from touchdowns.  I can't say that it starts as easy as a same sized zero tail rocker board because I don't have one to compare to.  But compared to a 71L zero tail rocker board that has a tail bevel, the little Froth foils up easier....not easier when it's under water obviously, but easier once on the surface.

Dwight (DW)

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Re: Wing Board Tail Rocker - Thoughts
« Reply #18 on: June 05, 2022, 08:11:47 AM »
Another Kalama inspired tail. This is Kane. My crystal ball says the rest of the world has these in production for the 2023 season.



« Last Edit: June 05, 2022, 08:15:11 AM by Dwight (DW) »

red_tx

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Re: Wing Board Tail Rocker - Thoughts
« Reply #19 on: June 05, 2022, 08:30:02 AM »
*****SHIM SHAM*****
Why is it that folks who shim feel like they need to inject shim sham talk into every thread?

The thread is about tail rocker which is a board shaping discussion. Please take shim talk to some other thread that I won't read. :)
Mkaay? Thanks
*****/SHIM SHAM******

One thing I think about the Kalama tail end, being tall and V Shaped on the new boards, is that they cork and then uncork easily, not sticking to the water. As you pump down you are pushing more volume deeper with less effort, then the volume corks the tail back up with less stick to the water.

I also have always felt that the longer the flat surface(even behind the foil box) the more glide in general(flat water). DW talks aboot this also.


-red

PonoBill

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Re: Wing Board Tail Rocker - Thoughts
« Reply #20 on: June 05, 2022, 08:57:43 AM »
Because tail rocker in the fin box area leaves the foil tipped at an angle. If you want your foil to be parallel to the deck then it's an issue to consider. m'kay. Were you scared by a shim as a child? Oh, and pushing more volume deeper with less effort? I'd suggest a quick review of high school physics.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

red_tx

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Re: Wing Board Tail Rocker - Thoughts
« Reply #21 on: June 05, 2022, 09:44:24 AM »
Pono, I get that, but It looks like the discussion was around the tail section rocker not the foil box location. Granted, they are close in proximity. Maybe I am missing something or interpreted the first incorrectly. I thought we were talking about flat bottom where the foil box is located and then the bit after that towards the tail. The bit after the foil box being the subject here. "Tail rocker" not foil box rocker.

-r
« Last Edit: June 05, 2022, 09:47:20 AM by red_tx »

Califoilia

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Re: Wing Board Tail Rocker - Thoughts
« Reply #22 on: June 05, 2022, 09:52:35 AM »
Been doing flat tail rockers since my first foil shape attempt long ago....


Started going no tail kick last year after DW made great sense on why we don't need them...


Found that chines all the way back out the tail made it tippier(?) and more work than was comfortable in windy/whitecap days so added some flat to the tail...

...that removed all of that. Love this board!
Me: 6'1"/180...5'1" Kings Foil Board...5'4" Kings Wing Board...9'6" Bob Pearson "Laird Noserider"...14' Lahui Kai "Manta"...8'0" WaveStorm if/when the proning urges still hit.

red_tx

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Re: Wing Board Tail Rocker - Thoughts
« Reply #23 on: June 05, 2022, 09:56:56 AM »
Pono, and now you have me thinking more about volume. No I am not a physics expert like you sir.

So then, in my lesser brain, I imagine pushing a V shaped wedge down into the water takes less effort than pushing a flat shape (With the same volume).

no?

-r

red_tx

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Re: Wing Board Tail Rocker - Thoughts
« Reply #24 on: June 05, 2022, 10:04:21 AM »
Been doing flat tail rockers since my first foil shape attempt long ago....


Started going no tail kick last year after DW made great sense on why we don't need them...


Found that chines all the way back out the tail made it tippier(?) and more work than was comfortable in windy/whitecap days so added some flat to the tail...

...that removed all of that. Love this board!

Califoilia, Looks awesome. Are you able to Stand up Foil Surf it, or Wing or both?
-r

Califoilia

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Re: Wing Board Tail Rocker - Thoughts
« Reply #25 on: June 05, 2022, 10:19:11 AM »
Pono, and now you have me thinking more about volume. No I am not a physics expert like you sir.

So then, in my lesser brain, I imagine pushing a V shaped wedge down into the water takes less effort than pushing a flat shape (With the same volume).

no?

-r
Not Pono, but yeah, that was my thought(s) with the more "Kalama styled" pin tail on my latest board above.

Like you, not a "physics expert", but it seems to work. This little board (5'1x27x102) paddles well and catches waves much better than my same-sized previous board with a kick tail, and more like my 6" longer 5'7x27x103 board with a kick in it also.

Califoilia, Looks awesome. Are you able to Stand up Foil Surf it, or Wing or both?
-r
That's a sup foil board that I have tried winging with, but find that the boxes and strap are a little too far forward to make it the perfect wing board.

So I use the flat tail board w/the chines out the back for winging, since it's boxes are about 3-1/2" further back than where I want them for the surf...

...the screws sitting on the board is where I'd typically have the front of the baseplate in the surf, even a little further forward depending on wing choice for the day. The chines out the tail are not a problem with this board for winging, since I'm not standing around trying to balance waiting on a wave the same way I'd be doing it in the surf.
« Last Edit: June 05, 2022, 10:25:28 AM by Califoilia »
Me: 6'1"/180...5'1" Kings Foil Board...5'4" Kings Wing Board...9'6" Bob Pearson "Laird Noserider"...14' Lahui Kai "Manta"...8'0" WaveStorm if/when the proning urges still hit.

Dwight (DW)

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Re: Wing Board Tail Rocker - Thoughts
« Reply #26 on: June 05, 2022, 11:36:26 AM »

PonoBill

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Re: Wing Board Tail Rocker - Thoughts
« Reply #27 on: June 05, 2022, 07:39:25 PM »
Pono, and now you have me thinking more about volume. No I am not a physics expert like you sir.

So then, in my lesser brain, I imagine pushing a V shaped wedge down into the water takes less effort than pushing a flat shape (With the same volume).

no?

No.

Not exactly quantum physics guys, it takes one kilogram of force to displace one liter of water (approximately) for any object floating in water. You already know this from considering the displacement of boards that can float you. Whether the force is applied by your weight, or by jumping up and down, one kilogram of force will displace one liter--it doesn't matter if it's pyramids, spheres, boxes, or a spaghetti noodle.

Here's the basic shim issue as applied to the SIC Manta--required two thick shims and the mast is still tilted back a little and the fuselage is still not quite parallel to the natural waterline. I'd add a third shim but then I'd need to use wizard hat hardware or risk cracking the tracks. I asked Mark why the board had so much tail rocker. He just shrugged and said "it's OK for surfing, but yeah, we don't do that so much anymore."



« Last Edit: June 05, 2022, 08:01:55 PM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

juandesooka

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Re: Wing Board Tail Rocker - Thoughts
« Reply #28 on: June 05, 2022, 09:42:18 PM »
Pono, I get that, but It looks like the discussion was around the tail section rocker not the foil box location. Granted, they are close in proximity. Maybe I am missing something or interpreted the first incorrectly. I thought we were talking about flat bottom where the foil box is located and then the bit after that towards the tail. The bit after the foil box being the subject here. "Tail rocker" not foil box rocker.

If you are focused only on the area past foil box, then you are talking about tail shape, tail kick, tail chines, etc.  Rocker is the curve on the bottom of surfboard, from the nose to the centre line, then from there to the tail.  Surfboards are curved like a banana. Foil boards vary, some having both nose rocker and tail rocker, some just nose rocker from the midpoint or a point forward of it, some being flat from midpoint through the foil boxes, others have substantial curve through to the tail (rocker).  The new Armstrong board being the most extreme example I've seen recently for extensive tail rocker...a couple inches from I recall.  The Fanatic sky boards had only a little, maybe half inch, with more for the shorter boards I think.

To measure rocker, hold a 6' ruler from the midpoint back, you may be surprised how many foilboards have some.  And yes, shims are for people who don't want any tail rocker, so shimming the back bolts makes it flat/neutral from the midpoint.

burchas

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Re: Wing Board Tail Rocker - Thoughts
« Reply #29 on: June 06, 2022, 05:50:42 AM »
Kane commented.

https://www.instagram.com/p/CebW8zYumkR/?igshid=YmMyMTA2M2Y=

Funny how Kane's comment is so relevant to this thread: "Touch of tail rocker and it’s super forgiving!"

The Kalama inspired bottom I've used on my last board is the reason for the thread. Although the secondary rocker along the bottom outline help in shaving all the volume from the tail I feel that I could have used some tail rocker.
in progress...

 


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