Contact   Imprint   Advertising   Guidelines

Channels on a surfboards

forum for kitesurfers

Very Frequent Poster
Posts: 3421
Joined: Thu Jun 05, 2003 3:37 am

Re: Channels on a surfboards

Postby BWD » Sun Nov 19, 2017 4:19 pm

Since it seems like there is some grasping and gasping here, some hints:
All strakes, keels, concaves and channels contribute to lateral and directional stability by creating force in proportion to their angle to the water flow.
For lifting strakes on vee bottom boats, this means they increase lift as well as help the boat go straight.
For channels on boards, this means they help tracking.
The nonsense about "accelerating water" reflects a truth: in case of deep concaves or channels that effectively change the rocker in the center as compare to the rails, the channel or concave fails to decelerate the water as much as would happen if the rocker were the same from rail to rail.
Etc. just think about the flow of the water along the board and how the design features affect it, it's not hard to get a grip on how designs work, beyond the mumbo jumbo.

Very Frequent Poster
Posts: 2647
Joined: Wed Oct 05, 2005 6:43 pm
Kiting since: 2001
Local Beach: Vejbystrand, Habo Ljung, Lomma
Gear: TW Surfboards 5-0
TW Surfboards hydrofoil board 120 and 135
Moses Fluente 550/590 + 330/325 and 633 set
North Mono 7, 9, 12
Ozone Reo 5
Ozone Hyperlink 9mUL, 7m
Flysurfer Sonic 2 13m
Brand Affiliation: None
Location: Sweden

Re: Channels on a surfboards

Postby TomW » Sun Nov 19, 2017 5:01 pm

Hej Plummet,
Everything is anecdotal. no one has any science.
I've noticed the boards I've made with Evo like bottoms cut through chop smoother, less slamming. They seem to float over the water when flattened out going fast on a reach and transitioning into a turn. I've found them to be really quick turning, almost squirrelly until you get used to it. Very little input needed to get them to turn.
The bottom has a 5-8mm concave thru the nose and middle, with additional double concave inside that, that fades somewhat towards tail. Then the tail has V, with channels added to double concave in tail.
They are very thin. The nose is 8mm, the center at tail 15mm, mid of board 15mm. Deck has over 10mm concave. They still have a good amount of flex.

Challenge to glass and Sand.

I set them up as quads, and I think the fin set up and spacing is vital element.
These boards are made for Northern Europe shitty windwaves and chop.
2017-03-11 17.18.52.jpg
2017-03-18 14.55.48.jpg

User avatar
Very Frequent Poster
Posts: 576
Joined: Wed Aug 27, 2014 3:29 am
Kiting since: 2003
Local Beach: 3rd Ave
Gear: Bates 4000, Dominator MX-10
Brand Affiliation: None

Re: Channels on a surfboards

Postby tegirinenashi » Sun Nov 19, 2017 5:16 pm

BWD wrote:
Sun Nov 19, 2017 4:19 pm case of deep concaves or channels that effectively change the rocker in the center as compare to the rails...
This one I can buy, especially that OR kiteboards proved to be very popular. One can also argue that concave improves edging. However, you know what? It is single concave. And when board designers started to incorporate more than one, it becomes ridiculous. What are those boards, wanna-be multi-hull boats?

User avatar
Very Frequent Poster
Posts: 854
Joined: Wed Sep 11, 2013 3:51 pm
Kiting since: 2010
Local Beach: Leeupan
Favorite Beaches: Langebaan
Style: Freeride
Gear: GK vSonic 6 & 11
Cloud C2 17
Progeni Mutare
Xelerator door
Hoff DD140
Brand Affiliation: None
Location: Johannesburg, South Africa

Re: Channels on a surfboards

Postby rynhardt » Sun Nov 19, 2017 7:54 pm

Cool topic!
My take on this is that any kind of bottom contours will affect the ride (obviously). Not just in terms of lift and drag, but also the board flex.
With no bottom features the plan shape of the board plays a big role.
Add channels and the plan shape becomes less relevant.
Add fins and the channels become less relevant.
Every wetted feature increases area, introduces drag, and creates lift. Fins are more efficient than channels because they are higher aspect.
But if you ride obstacles fins are not great.

Frequent Poster
Posts: 473
Joined: Sat Mar 13, 2004 6:18 am
Kiting since: 0
Brand Affiliation: None
Location: Winnipeg, Canada

Re: Channels on a surfboards

Postby zerogee_ca » Sun Nov 19, 2017 8:42 pm

Seems like marketing to me. What was old is new again. Some of the channels seem ridiculous to me. Do the advantages in ride and performance of a board with channels out weight the added time and complexity of designing and building a board with channels? Why are there not more boards with channels? Too hard and expensive to make??

I have been able to get the ride /perfomance I want by changing fins. Fins can make or break a good board.

My current board, a Tomo inspired board from North, has a simple rail to rail single concave with a double concave in the nose. Still riding the factory fins too. I can't believe how much fun this board is for such a square board. Never wishing it did anything better. How much more fun /better would this board be if it had channels?

Hoping to demo something in Hatteras next spring to see what they are all about. But have not had any luck the last 2 years with this.

Medium Poster
Posts: 97
Joined: Wed Aug 05, 2015 3:45 pm
Kiting since: 2013
Local Beach: Exmouth, UK
Gear: Foil, surfboard, twintip & 8-18m kites
Brand Affiliation: None

Re: Channels on a surfboards

Postby baxterbradford » Sun Nov 19, 2017 8:54 pm

plummet wrote:
Sun Nov 19, 2017 10:54 am
I won't if anyone has done some flow modelling on channels to what impact they have.
This is worth a watch where they've done flow modelling on different Firewire designs, though not specifically commenting on the effect of the channels, you can see what they are doing.

Very Frequent Poster
Posts: 2517
Joined: Fri Sep 11, 2009 3:15 am
Kiting since: 0
Style: Toilet Stance
Gear: Flexifoil Blade 4.9 / Brunotti 2face

Re: Channels on a surfboards

Postby longwhitecloud » Sun Nov 19, 2017 11:05 pm

3 things at work

Going slow on sloppy waves or just cruising
Going fast on waves while cruising
And turning

If you want to turn a wider tail (not too wide), a pointy nose(most of board out of way when u pivot - short cut off noses the same), Fin positions, fin size( large= more lift) and tail rocker are important.. more so than channels/concaves.

I don't fully understand channels that are equal depth almost the full length of the board other than for tracking and some concave like lift maybe.

Interesting stuff. I just got a v3 rocket (lost mayhem) it turns sooo well, shame it would fall apart quickly for kiting.

Good turning surfboards can have absolute shit tracking. I guess that is why boards like the Nugget with straight rails sell well, good for cruising comfortably.

Medium Poster
Posts: 73
Joined: Sat Aug 19, 2017 7:01 am
Kiting since: 5
Gear: Best
Brand Affiliation: None

Re: Channels on a surfboards

Postby bjw » Sun Nov 19, 2017 11:28 pm

I'm not a fan of channels. I feel its a bit of a fad in kiting. It'll probably help you get up wind. But like in surfing, not great in chop. Wakeboards are different, it's in glassy waters. I find they aren't great for top turns on a good wave. They don't slide as well or correct as well.

It's funny a mate got a custom Vanguard type board made up, then liked it and got another made. Same board, but they screwed up and made it without the channels. He finds it far and above better than the first one he made.

User avatar
Very Frequent Poster
Posts: 10140
Joined: Mon Feb 16, 2004 5:36 am
Kiting since: 0
Brand Affiliation: None
Location: Oahu

Re: Channels on a surfboards

Postby tautologies » Sun Nov 19, 2017 11:50 pm

baxterbradford wrote:
Sun Nov 19, 2017 8:54 pm
This is worth a watch where they've done flow modelling on different Firewire designs, though not specifically commenting on the effect of the channels, you can see what they are doing.
That video is a bit annoying and a bit interesting. Maybe I just need more coffee, but damn. I generally can listen to a shaper speak intuitively about how they make certain choices, but these guy talk (REALLY SLOWLY) about CFD as if they provide definitive answers. It might be a starting point, but a fairly common joke about CFD is that CFD stands for "colorful fluid dynamics". There is sooo much nonsense in the surfboard industry.

Johnny Rotten
Frequent Poster
Posts: 467
Joined: Thu Dec 04, 2008 1:50 am
Kiting since: 2006
Style: Surf and wake
Gear: Vegas
Hand made boards of pure excellence
Brand Affiliation: None
Location: No fixed address

Re: Channels on a surfboards

Postby Johnny Rotten » Mon Nov 20, 2017 12:01 am

I've experimented extensively with side cut out line board shapes and channels.
Vader, Stallion, Evo type boards are absolutely fantastic.
As are heavily channeled twin tip boards like the tona pop.

Also some interesting stuff here about concaves as well as underwater flow video

Return to “Kitesurfing”

Who is online

Users browsing this forum: GregK, lovethepirk and 16 guests