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Channels on a surfboards

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plummet
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Channels on a surfboards

Postby plummet » Sat Nov 18, 2017 7:58 pm

What do you guys think the advantages are of channels on a surfboard?

Does it give you more stability? more grip on a bottom turn? better upwind?
Is there any disadvantage that you can see?

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tautologies
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Re: Channels on a surfboards

Postby tautologies » Sat Nov 18, 2017 8:31 pm

Channels work!! Now if you have that deep channels across the length of the board I am not sure I understand the benefit intuitively. It would seem the board would have some issues as water doesn't hit on a straight angle, but as I have not ridden the board I am also not saying it will not work.

I would say clearly defined channels towards the tail, with a more understated channel through the middle combined with a gradual rail (from round to sharp) would be a good option.

Now to speculate a bit. I think a deep channel across the board might give some unintended consequences when you turn. Deep and defined channels at the tail is really nice. it gives you bite when you need it most off the top of the wave.

...I would try pretty much anything tho.

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Re: Channels on a surfboards

Postby tegirinenashi » Sat Nov 18, 2017 9:16 pm

There are holes for 5 fins at the OP images. I bet nobody ever mounted all 5 fins at once, so in terms of performance I would have more worried about turbulence caused by those open fin holes than channels. And the fact that nobody cares about this turbulence implies that the effect is minuscule.

To summarize: channels is yet another marketing gibberish. They look interesting to a prospective customer, that is all to it. I'm not adding it to the Official Thread of Pointless Innovations, because they were invented elsewhere (not in the kitesurfing industry).

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Re: Channels on a surfboards

Postby Bushflyr » Sat Nov 18, 2017 9:54 pm

tegirinenashi wrote:
Sat Nov 18, 2017 9:16 pm
To summarize: channels is yet another marketing gibberish. They look interesting to a prospective customer, that is all to it. I'm not adding it to the Official Thread of Pointless Innovations, because they were invented elsewhere (not in the kitesurfing industry).
Says someone who has no clue. :roll:

Channels of various sorts are %100 proven to work in many different hydrodynamic aspects. Look at water skis, look at boats, look at finless park wakeboards, look at basically any performance watercraft and you'll see channels or chines of some sort.

Full length channels under a surfboard, a la Tomo or Mako, help keep the water flowing straight instead of slipping out from under the sides of the board and improve lift. Channels or cuts under the tail act as mini-fins and improve grip in the turns. Basically the same as chines on a boat hull except cuts instead of protruding from the hull.

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Re: Channels on a surfboards

Postby plummet » Sat Nov 18, 2017 11:46 pm

An interesting discussion.

How do channels effect upwind performance given that when cracking upwind the water flow as the same angle as the waterline. IE running at an angle to the chine/ channel. Does the channel give you extra drive and better up angles or more drag and worse upwind angle?

PS In this instance I'm talking about a channel that runs full length of the board.

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Re: Channels on a surfboards

Postby BWD » Sun Nov 19, 2017 12:10 am

I think channels are ok, have enjoyed them on some boards. As a design element, they have to work with the total design of each board. Some boards have different types of channels, for different reasons, with different feel, different performance and intended conditions etc.
The mention of chines in boat hulls is interesting, chines and strakes are rarely seen in boards but probably have good potential, maybe extra challenge to build. Glassing channels is chore enough!
Last edited by BWD on Sun Nov 19, 2017 4:06 pm, edited 1 time in total.

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Re: Channels on a surfboards

Postby jakemoore » Sun Nov 19, 2017 12:56 am

What kind of work do they do?

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Re: Channels on a surfboards

Postby longwhitecloud » Sun Nov 19, 2017 1:16 am

They can accelerate water through the tail resulting in better turning, they can cause drag reduction and a slight lifting of tail out of the water. Also help tracking in a straight line.

Means nothing if not done right tho and can make things far worse.

I'd trust tomo over a kiteboard shaper for channels, and a kiteboard shaper over tomo for kiteboard strength etc..

I picked up a FireWire helium the other day... Insane weight.. will stick to your feet!

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Re: Channels on a surfboards

Postby tegirinenashi » Sun Nov 19, 2017 1:31 am

Bushflyr wrote:
Sat Nov 18, 2017 9:54 pm
...Channels of various sorts are %100 proven to work in many different hydrodynamic aspects. Look at water skis, look at boats, look at finless park wakeboards, look at basically any performance watercraft and you'll see channels or chines of some sort...
Citation needed. Look, if channels are in any way better than flat surface, then there must be some kind of optimum. In the number of channels, their shape, etc. What we actually see is a wild zoo of different "designs". Aren't those designs supposed to compete between themselves too (and exhibit the winner)?

BTW, the convex shape of the board bottom is a kind of a channel. However, advantages of convex shape are much easier to believe, because it is a smooth curve (and therefore much more likely to be a solution of an optimization problem). For convex channel, the optimal number of channels can't be anything other than 1. However, the fact that board designers were compelled to follow Gillete path and increase the number of channels hints that probably minuture concave shape doesn't really matter too.

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Re: Channels on a surfboards

Postby plummet » Sun Nov 19, 2017 10:54 am

I won't if anyone has done some flow modelling on channels to what impact they have.


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