If anything, I’d probably do 8x23x2.75 or 3". Simple 50/50 rails. Concave in front third. Flat to belly in second third and then flat in tail.
Would need width at different length intervals to find a good location.
I’m really interested in following this one, it’s an interesting design.
7" tail x 16" tail (@12")x 23 mid x 15 nose
What would your max tail rocker normally be?
I’m open to suggestions. I’m sure I can shape it into the channel, whatever it needs to be.
I’m designing a Channel Fish this summer. Retro Fish planshape but using a channel in place of a butt crack. Since the channel exit is at tail’s end, channel depth is easier for me to calculate. I use channel depth to calculate channel length.
However, I’m no pro at determining ideal tail rocker. Positioning the channel exit in front of tail’s end makes channel depth and length estmates a bit more challenging. So knowing your preferred tail rocker without a channel would give me some place to start for determining channel depth and length.
Basically, for a longer board, I would position the channel exit(s) near the tail where the board is from 12”-18” wide. For a single channel, I would locate channel exit closer to 12” wide. For a twin channel, I would locate channel exits closer 18” wide.
Found this rocker guide at Greenlight Surf Supply:
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First draft CAD graphics of a slab blank for my 13.3” X 26.14” Coanda channel data (images below) — CAD work by Jim (aka jrandy).
This blank could be used for a variety of square-tail style short-board surfboards (Retro Fish, Mini-Simmons, etc.)
Nice work. Is the one on the right basalt cloth? Where are you located? I’ve tried to find a supplier in Southern California to no avail. The only option was to order from Australia.
Your curved channel reminds me of Jobson twinzer fang tails.
One on the right?
Which post number?
The channel doesn’t work with tail rocker.
Also the channel walls must have a hard 90 degree edge where they meet the bottom of the board.
And the channel bottom must be flat (width-wise), no convex or Vee.
Basically the channel functions as a finless fin.
EDIT:
OK. I see you’re asking about post #6. Both boards are cut from charcoal grey 6-pcf XLPE (cross-linked polyethylene closed-cell foam) — no skins basalt or FG.
BTW I’m landlocked in KY for a while now.
Just noticed the USPTO link in post #18 is not working.
These figures (16 & 17) show how the channel can be added to more traditional surfboard planshapes.
Looks like the USPTO link in post #9 has stopped working too.
These figures (14 & 15) illustrate the water flow patterns in the Coanda Channel.
i saw from years ago that you would be mad if somebody copied your channel, what abouut pyzel and many others in lots of their models or custom shapes? you cant control a single shape and mainly with a patent that you would like to have respected. it makes no sense.
SEBASTIAN AGUIRRE,
The Coanda Channel and its applications in Surfcraft is what is patented. The USPTO patents explain what is protected from commercial production (US Patent Nos. 10,974,797 and 11,649,013). They are available for public viewing at the USPTO website (Basic Patent Search).
Do you have a link to the Pyzel surfboard models (“and many others”) you are referring to that have Coanda Channels?
I searched but see no pictures so far of Coanda Channels in Pyzel surfboards.
I do see several Allan Byrne style linear channels.
Fin boxes have been patented. Why are patents for fin boxes (Bahne,1971; et.al.) acceptable, but not patents for my Coanda Channel?
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This was Thomas Vilmin’s 3D interpretation in Shape3D — during a brief FB discussion we had (May 2024) — of the first Coanda Channel I designed. Took him 5 minutes to create. Not an exact rendering of my first channel, but impressive nonetheless.
The image can be 3D rotated through multiple positions.
The first video demonstration with air gives an accurate explanation of the Coanda Effect.
The second video demonstration explanation is inaccurate.
In the second video, the curved surface of the ball pulls the water jet onto ball. An equal but opposite Newtonian force (reaction) pushes the ball against the water jet. The upward force of the water jet causes ball to rise.
Option 2: Coanda Channel in a Fish variant without a pointed nose. I’m partial to boards with noses that don’t have flesh piercing points. Board design intended for “paddle-in” prone riding but can be used for stand-up surfing also. CAD work by Jim (aka jrandy).
@stoneburner -
Looks like you are on your way to having a surfboard!
Latest concept rendering, needs a little more work on deck/rails/tail before it is ready to go.
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