Author Topic: Wing Board Tail Rocker - Thoughts  (Read 9807 times)

burchas

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Wing Board Tail Rocker - Thoughts
« on: June 01, 2022, 07:52:36 AM »
I hear a lot of negative feedback on forums but some very popular designs include tail rocker.
Starboard Take-Off, SIC wing boards, North Seek (by way of Indiana Wing board), PPC Soar come to mind.

Any deep thoughts on the subject?
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StellaBlu

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Re: Wing Board Tail Rocker - Thoughts
« Reply #1 on: June 01, 2022, 07:58:24 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.  Tail rocker will make the board ride nose-up if the foil isn't shimmed or otherwise designed to accommodate the angle.

You can always adjust for the tail rocker with a baseplate shim, but I would rather start with a flat mount surface and minimize shimming wherever possible.

JohnnyTsunami

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Re: Wing Board Tail Rocker - Thoughts
« Reply #2 on: June 01, 2022, 09:03:11 AM »
Do you mean tail rocker, or a ďtail kickĒ? Big difference. Iím opinionated about tail kicks serving no purpose whatsoever except to slow boards down. I can hear and see my tail kick board sucking water up while Iím pumping onto foil and can feel the lack of that drag on my straight tailed board which works better at near foiling speeds.

Tail rocker is different. My home shape is absolutely flat in the back half. I think itís the fastest design for getting on foiling but it has drawbacks and my next board will have slight tail rocker in the back half. This is because I use a Tuttle box and can angle it how I like, but angling the foil slightly down will make the board ride level at speed.

The tail rocker is more for starting, pumping into or with waves on crazy sea state can be really hard. Once the board starts moving, the tail lifts so much it pushes the nose under little waves and you fall. Having some rocker would allow you to angle the board up slightly and mitigate this issue. Not sure how it would affect balancing while slogging, maybe positively?

jondrums

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Re: Wing Board Tail Rocker - Thoughts
« Reply #3 on: June 01, 2022, 09:14:41 AM »
I now use two different boards for SUPfoil and WINGfoil.  I designed them both.

My wingfoil board has absolutely no tail kick and less than a degree of rocker on the back half.  It gets on plane super fast and comes up off the water smoothly.  but it is completely terrible to SUPfoil on waves.  The back of the board sticks in the water when catching the wave and won't allow me to bring the nose up quickly to get on foil on the drop.  It really is bad and nearly un-rideable.

My SUPfoil board has a bunch of tail kick with no rocker on the back half - and gets on waves super easily - one big paddle pump as the wave picks up and off we go.  It wings ok, but doesn't come up to speed nearly as easy.

surfcowboy

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Re: Wing Board Tail Rocker - Thoughts
« Reply #4 on: June 01, 2022, 08:26:16 PM »
I say no to both. This is what shims are for. With shims you can have more than one foil.

PonoBill

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Re: Wing Board Tail Rocker - Thoughts
« Reply #5 on: June 01, 2022, 09:03:18 PM »
Ditto what Stella said. Tail rocker on a wing board seems like a pointless carryover, like an appendix that doesn't do anything useful and might cause problems. The SIC manta I bought has quite a bit of rocker. I had to shim the crap out of the base plate to get it to work.
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.

Slyde

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Re: Wing Board Tail Rocker - Thoughts
« Reply #6 on: June 02, 2022, 03:13:06 AM »
Well it depends on what you want the board to do and your level of experience. If you are a beginner and riding a relatively big board where you generate board speed to get up on foil you want a board with no tail rocker to help this process. But once up on foil you will find that the board tends to ride nose down and is uncomfortable to ride as there is not enough front foot pressure.
If you are more experienced and riding a smaller board where you pump the wing and foil to get up on foil then you will be much less concerned about the behaviour of the board transitioning off the water and far more concerned with the attitude of the board while flying. You will want some tail rocker to have the nose of the board ride a bit higher to balance your feet out to get enough front foot pressure. This is more accentuated as you begin to ride faster and faster and generate more and more lift from your foil. In that scenario you need the nose up a little to  get a nice balanced foot pressure. We learnt this lesson on kitefoil boards a while back. Have a look at the rocker on a kitefoil raceboard. Its quite a banana, but feels very comfortable to ride at speed. Compare that to a SUP foil board which is generally quite flat rockered and often rides uncomfortably nose-down. I have built a series of boards from the very beginnings of the sport transitioning from 115 to 100 to 85 to 65 to 60  to 58l. I have added progressively more tail rocker as my experience level increased except for the last 2 boards where i settled on the same more pronounced rocker line. Increasing the rocker absolutely did not make any meaningful difference to takeoff once I was past that beginers stage of using board speed to get on foil. And that is irrespective of HA or low aspect wings. Have a look at what Ken Adgate is producing for the  high-level winger in the Bay area and you will see where this is heading. If a board is properly designed it should not need to be shimmed. The same goes for tail wing shims. Its just an excuse for poor design.

Dwight (DW)

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Re: Wing Board Tail Rocker - Thoughts
« Reply #7 on: June 02, 2022, 03:41:13 AM »
Kalama tail beats them all.

StellaBlu

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Re: Wing Board Tail Rocker - Thoughts
« Reply #8 on: June 02, 2022, 06:06:36 AM »
You will want some tail rocker to have the nose of the board ride a bit higher to balance your feet out to get enough front foot pressure. This is more accentuated as you begin to ride faster and faster and generate more and more lift from your foil. In that scenario you need the nose up a little to  get a nice balanced foot pressure.

I respectfully disagree with some of this.  If your foil is properly positioned and set up you should be able to balance foot pressure with a flat tail board.

Doesn't KA design all his boards with tuttle boxes where you can adjust the angle of the mast (I haven't seen his boards in person - so I am not certain of this)?  If thats true, then tail rocker doesn't matter since you can counter it with the angle adjustment (exactly the same as a shim).

JohnnyTsunami

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Re: Wing Board Tail Rocker - Thoughts
« Reply #9 on: June 02, 2022, 08:39:09 AM »
Iím not aware of any way to adjust the angle of a Tuttle mast once a board is already built. I was asking Ken the other day about his tail rocker and he said that you need some so at speed you are running level and not nose down. Iím going to try 2 degrees or so next build.

juandesooka

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Re: Wing Board Tail Rocker - Thoughts
« Reply #10 on: June 02, 2022, 08:48:24 AM »
When I was heavy into making board last year and couple years prior, I'd measure up any board I got my hands on.  Most surf and sup foil boards had some tail rocker from the boards mid-point, some a lot more than others.  As it was explained to me, this gives the board a more "nose up" feel, like riding a snowboard in powder.  Watching a surfer on a no tail rocker and low nose rocker board, it can look like the board is angled down sometimes, which gives the wrong feel.  I think this is more for surf foil, where you paddle with the nose out and board angled a little up -- so the foil fuselage is horizontal/level at this angle.  But for sup foil, you paddle the board flat, so want minimal or no tail rocker to achieve same thing.  Wing foil perhaps the tail rocker could help with take off, getting the angle at the top of a pump -- but that is probably more about low aspect pumping style (up and down) vs high aspect (more like a jet taking off).  So I suspect that may be part of this, the trend of HA foils has made boards more likely to need flat tails, same with the no tail kick trend (ginxu notwithstanding).

Latest board I checked out is the new Armstrongs, with their Forward Geometry.  Designed for ride further forward. The foil mount is close to the center of the board. The tail rocker is extreme -- like a surfboard.  That's completely opposite of what most boards are now and what most of you are saying, yet one of the most popular boards in the world. 

So...how to reconcile that 180 degree difference in design opinion?  The cynic in me says one logical answer is that it makes an unsubstantial difference either way.  Subtle differences in the ride, good or bad, for different conditions ... but fundamentally both work. Particularly as when you're powered up the ease of take off is completely irrelevant, you pop up in 1 second on first pump. As well, for intermediates and up -- I now often spent 30-60 minutes at a time without a touch down or wipeout, so who care about bottom shape when I am in the air?  A lot of this stuff is shiny fishing lures to attract fishermen rather than fish.  ::)     :o ;D

clay

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Re: Wing Board Tail Rocker - Thoughts
« Reply #11 on: June 02, 2022, 10:11:46 AM »
Guys I know with the new Kalama tail say it's a game changer and they can get up on foil easy even in flat water where on other shapes they could not.

Tail shims are all about fine tuning a foil to a riders style and to match the conditions or wave size/power.  The best guys on ML foils shim the tail when need be, the older unibody design had a shim in between the mast bolts to bend the fuse and change the angle of the tail.

Two bolt tuttle masts are easy to shim (haven't tried the 3/4 bolt tuttle masts):
https://www.youtube.com/watch?v=tP7Q9-2p-gI

Aloha, I welcome and appreciate all responses of positivity and good feeling.

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kwhilden

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Re: Wing Board Tail Rocker - Thoughts
« Reply #12 on: June 02, 2022, 12:13:03 PM »
I think the dual-stage tail rocker on the Starboard Take Off is really interesting.  Could be a way to get the best of both worlds.

I copied this on my new board.... which is still getting glassed.
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PonoBill

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Re: Wing Board Tail Rocker - Thoughts
« Reply #13 on: June 03, 2022, 07:02:29 AM »
Iím not aware of any way to adjust the angle of a Tuttle mast once a board is already built. I was asking Ken the other day about his tail rocker and he said that you need some so at speed you are running level and not nose down. Iím going to try 2 degrees or so next build.

Actually, it's fairly easy to adjust the angle of a tuttle with shims, it's the only thing you CAN adjust unless you change the fuselage-to-mast attachment point.
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.

burchas

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Re: Wing Board Tail Rocker - Thoughts
« Reply #14 on: June 03, 2022, 08:07:31 AM »
...The SIC manta I bought has quite a bit of rocker. I had to shim the crap out of the base plate to get it to work.

Bill, I'm curious as to the conversation that took place when you told that to Mark... He is an Axis rider if memory serves.
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