Great question. Vac bagged flat deck first, Shaped the 5" or so of nose with 60 seconds of planer use and a few minutes of hand sanding to match rail profile per bill wurts. The next one that is non wood will vac bagged cf or other exotic glass will probably do bottom first and put in simple jig to get the nose flip, then shape deck and vac bag top. vac bagged first floppy eps surfboard blank in 1985. never have had a problem changing or keeping intented rocker under vacuum .
Charlie.....I never forget Ewa....with Diamond Head in the distance on 2nd photo behind the gate!! Had many go outs there in the hood...with not another surfer in sight. Fond memories.
Charlie's build is the first complete prototype of my channel project. Shaped, veneered and glassed with Charlie's "wizardry.” A work of Art!
The CAD and CNC cutting "magic," for the bottom channel as well as planshape and nose-rocker templates, are the work of Jim (jrandy).
The physics, math and design -- bottom channel, planshape, nose rocker -- are my work. I filed a patent application for the bottom-channel design in 2019. I did this to protect myself from the large commercial board manufacturers.
Below are my favorite CAD graphic that Jim created from my design data and me displaying Charlie's sculpture shortly after I received it.
Just chuckling- we 'alternative forms' guys do look alike.
And good- while the numbers might not be big enough to pay fpr patent defence in court, still, it'll slow them down some.
Wow, while I'd love to play with it, between the virus and age and infirmity I would be the world's worst test pilot. Plus my access to CAD/CAM equipment is limited, my cousin has a lovely setup but he's working with metal, small production runs of things like firearms parts. Really, really nice firearms parts, though.
Doc, I bought this Galera board from Bob Green in Queensland, Australia and rode it until a year ago.The bigger the wave the better it rode as the deep channel needed a lot of water to function.
I expect it will be the same with this cool looking missile from BB30 and Bill.
(chuckling) Bob is on here, he and I have been corresponding for years about paipos, life, the universe and everything. Great guy.
I have always been curious about the Galera model, the very curved bottom always had me wondering how it would hold an edge on a steep section. Could you ( or Bob) chime in on that?
I probably dropped off the latest e-mail chain we had and have been sleeping on the job on this thread (aka my attention has been focussed elsewhere lately).
A word about John Galera - I owe him a debt for sending me one of his paipo boards in 2004 which has sent me on a trajectory of experimenting with all manner of bellyboards.
These boards hold an edge in steep hollow waves. As with the current boards I ride, the single biggest problem is going fast from a hollow section to a full, flatter section where you have to regain an edge. In the footage where John is sliding down the face, this looks more to be a product of being where the lip impacts. The bounce on the first wave is something experienced when riding bellyboards and the shock isn't absorbed in the same way a stand-up surfer can absorb this force.
Regarding the current board, my initial reaction is that the tail channels look too bulky. However, having said that, it depends on what type of wave is intended to be ridden and what experience is sought. I've ridden boards people have raved about and not felt the same way. I also tend to like more curved lines (I can see how this can go wrong as I type) .
However, the only really proof is in how it rides. Great workmanship there.
Charlie’s skills and craftsmanship are undeniable. I really like Charlie’s interpretation of my suggested rail shape.
I encourage Jim (jrandy) to take a bow. His CAD and computer shaping of the channel and planshape templates were a significant part of the project. Jim was able to do what standard surfboard shaping software/shaping machines could not.
It took 3 people to give this prototype bodyboard its final physical form.
this build thread ans folloing dicussion is rad, make me pumped to get into the two belly boards i have half shapped in the shed, two edge railed beasts, inspired by greenough.
This thread is just chucked full of Talent and Skill. Charlie brought it to life. Cool collaboration between Bill and Jim. Design and program. Fantastic guys! My hat is off to the genius in this. Much respect gentlemen. Lowel
like
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That which can be assorted without evidence was read in an illegal magazine.
The physics suggest the channel will create an area of low (negative) pressure under the tail. The drag should be low. The expected performance advantage would be improved tracking and directional control, without fins.
I'm curious, why did you insert the channel instead of simply shaping the channel into the original foam blank?
The channel design has some very specific curves and dimensions. It would be very time consuming and difficult to precisely shape it by hand.
Jim computer shaped my design -- to hundredths of an inch -- as a panel that can be grafted into a blank of any shape. Jim called it a cartridge, now referred to as a "channel cartridge."
The smaller size of the channel cartridge facilitates more cost effective shipping from MN to HI, KY or anywhere else. This allows us to send it to test pilot/shapers.
Now, given a set of fixed dimensions for the cartridge, wondering if you've got an ideal planing area mapped out to work with it? Or is that part of the testing? Thinking about experimental design: if the cartridge was made up as, say, a waterproof subassembly ( completely surfaced, glassed, etc) that could be swapped in and out of several different boards with varying characteristics you could get some great data. I'm sure you can picture what I'm thinking about.
Thanks, looking forward to how this works and develops.
You are at the trailhead now. But the number of divergent trail choices at the outset is enormous.
Early on, I considered interchangeable channels. But I couldn't even find somebody to computer shape a foam channel. I had done a couple of projects with Jim before. So when traditional surfboard shaping software/machines were a bust, I went to my garage CNC/CAM magician, Jim. Bottom line, it was clear that the complexity of Interchangeable channels meant real world protypes were well beyond reach in the immediate future.
The number of variable combinations is immense. I used the SWAG method to determine the initial channel dimensions. The first channel was designed for a 42" BB. Then using the SWAG method, I designed a channel for a 48" BB. I sent Charlie both. He chose to build the 48" BB first.
I'm still not convinced the current dimensions are optimum. All of my curves are defined by equations. I can adjust them for any combination of dimensions desired. One-offs are doable if Jim has time outside his day job.
At the moment, my belief is the planing area around the channel is most critical -- referred to as the tail "pontoons." But I do not know what the "optimum" channel dimensions are. I suspect there is a desirable low/negative pressure -- too high or low diminishes performance. This will be affected by velocity.
I tried to recruit several Sways shaper test pilots. By dumb luck and pure good fortune Charlie was the first Sways adept to shape a board.
We still have no test pilots. As offered previously, if Jim has the time, I am happy to work with him to make and ship you some graftable foam "channel cartridges."
The channel is intended for use in several types of surfcraft. However, the original objective was to improve BB tracking without fins. I'm liking the idea of a "Finless Fish" somewhere in the near future. But I think it could be used effectively in combination with a twin-fin set up (quads?).
Bill
BTW for those not familiar with the jargon, SWAG = Scientific Wild Ass Guess.
Right? There's a few ways to make a swappable cartridge, I think, fairly straightforward, but for the moment .... and it's real nice to see a SWAG in this field, the vast majority of 'surf science' is what a friend of mine described as 'hand waving and hope'. I come from a marine engineering/naval architecture background-we like numbers.
Measuring things is the key, and difficult- waves are inconsistent, speed through the water is easy enough in a tank test but speed, say, versus angle of attack on a 3D curved moving surface? Owning, say, your very own wave pool or some river you could play with to make a standing wave?
In any event, yeah, I suspect the ratio of area of the pontoons ( or, if you like, steal the term 'sponsons' from the planing surfaces on racing hydroplane boats) to the channel volume, say, is important. Or, perhaps, the bottom surface actually in contact with the water at a given speed? The volume could be measured, mask it off and pour in water maybe, but given the consistent shape of the channel I'll bet the area of the back end of it would be good enough. The width versus the height too, that ratio, but that's a whole other thing. As you say, the sheaf of options is enormous. Spreads out like a peacock's tail ( or, considering the date, a turkey's)
Which has me thinking about maybe model testing? To narrow that spread? If a fairly fast-flowing stream (or for that matter any reasonably deep flowing system) was available? Foam, or for that matter painted wood, models scaled down accurately, measure drag, measure resistance to sideways force, measure force exerted when the angle it pointed was changed? While test pilots/actual use would give you a very general idea of desirable characteristics, this model testing might be a real good way to fine those down quickly and inexpensively/easily?
Don't have time for an expanded response at the moment. Maybe later when I have more time to mull over my words. Gotta get in a fill coat before dinner -- my weather window is closing quickly.
Between the two of us, we have barely identified the tip of an iceberg. I see at least two graduate thesis projects in what we have discussed so far.
I have a broad-base undergraduate science background. I am a retired scientist, graduate education ranged from medical science to aquatic science. My professional research would fall under the broad topic of aquatic science.
My rabbit hole for this channel project, curves in two dimensions and depth...
(chuckling) Ya think? The real trick is in writing the grant applications to fund all of this R&D plus a few beers.
Times like this I especially miss Terry Hendricks. He had, among many other things,. a real gift for devising nice and inexpensive ways to test things.
Modelling hulls and hydrodynamics, numerically, well, they used Crays to do America's Cup boats in flat water a decade or two ago. Million dollar plus project. Computing power and the cost of it have changed a lot since then but modelling a surfcraft on a moving wave I would estimate to be orders of magnitude more number crunching, would have to get a good basis/basic data to work from to begin with. Maybe the Navy has something like that for hull design, I do know I couldn't even attempt to write the software on the best day I ever had.
Glad you reminded me, they're giving rain for tonight and I have to get a tarp over something I won't get to installing or moving in the dark. Back to earth, as it were.
My initial fear would be that the first prototype is the 48" and not the 42", That is a very big/floaty "bodyboard" and will be a handful in its self, which I think will make it hard to derive if the channel design is working because of the fight I think the size of the board will put up.
slater tried out a similar concept with Merrick, their design had a hole through to the deck to allow air from the top into the channel.
As I come from the 'potato chip (or 'crisp', depending onm where you are) era of paipo boards, I'm kinda along with you on this. The good news is that what with the CAD/CAM aspect of the channel shaping, scaling it becomes trivial. Really, it's all about planing area, buoyancy doesn't really help one way or the other when it's that size.
I hadn't seen the Merrick/Slater project, I recall one from the '70s that had an air scoop forward, air channels in the foam and a series of transverse depressions in the otherwise flat bottom. The idea, as I understood it then, was to make an air layer between the bottom of the board and the water, leading to a helluva lot less friction/drag and so much higher speeds. The guys associated with it- Aipa, Barry K. and others, if memory serves - were pretty good but nothing really came of it, no idea why or why not. A wild guess would be a combination of not enough airflow and once that was sorted, controllability issues. Similar to a hovercraft in a crosswind -
buoyancy doesn't really help one way or the other when it's that size.
On a bodyboard if you have a wide board that has a lot of rail volume it slips out, a less buoyant knifey rail can sink it in easier and not pop out of the wave face and side slip.
I have an old fat bodyboard that I use as a groveler and have taken it on trips to g-land out of interest. Over shoulder high it is a lot harder to sink the fat rail and keep from losing the edge. My performance bodyboard is 42" and my fat groveler is 42".
Also that board may also have problems holding a rail if the bottom to rail is a hard edge. it needs to be at least a 16th round over. My glasser put a hard edge there once on a paipo of mine and (through the water release would slip very easily) rounded it over with sandpaper myself and the grip was back.
I wonder if you could make a test version of this out of an old bodyboard pretty easily just cut your channel outline in the bottom slick peal that bit up, shape out the foam below and then glue the slick back down and a couple of filler pieces.
Right? I dunno if it's the buoyancy of the rail so much as the additional planing area of the fat rail itself lifting it out of the water and the way it holds goes all to hell.
I'm a firm believer in thin boards, considering what I started out with that''s no surprise- Newport Paipo Concave Vector
Nodding in agreement with a slight chortle... no sh!t.
A fine spray of coffee descends, followed by a loud guffaw
Exactly.
And I haven't solved a calculus problem since autumn of 1972...
I tutored, likely as some sort of penance for my many and varied sins, college level maths, physics and chemistry in the '80s and with me in my 30s, already showing signs of senility , as a retread returning engineering undergrad. Including calculus. Having a memory with a retention ability akin to the water holding qualities of chicken wire, it was good to review and reinforce that stuff as otherwise I would have forgotten it before the echoes died in the lecture hall.
That was, though, at least three decades back. These days, I find myself challenged by problems like
3X+1=10. Solve for X.
A ladyfriend's high school daugher has, unsurprisingly, an algebra class, and her mother emails me the more annoying word problems under the sadly mistaken belief I can be useful. Heaven help me when she gets to Geometry, though if she's relying on my help to advance that's rather unlikely to happen.
drawn out per Bill Wurts, AKA stoneburner's, plans on fresh cut 1lb foam from scrap block
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folowing plans
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insert slot cut out
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more
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I'm curious, why did you insert the channel instead of simply shaping the channel into the original foam blank?
Send me your dinged, damaged, and yellowed.
BackyardBullard.com
great question. In mass production the simple solution would be to glass, cnc or replicate cut and glass cut out section.
look from back. reinforcement bottom and top
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wood on top and bottom in bag after final profile shape
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Light soft eps, "thick" wood skins, no stringer, no rocker table on photo, how do you keep rocker under pressure ?
Great question. Vac bagged flat deck first, Shaped the 5" or so of nose with 60 seconds of planer use and a few minutes of hand sanding to match rail profile per bill wurts. The next one that is non wood will vac bagged cf or other exotic glass will probably do bottom first and put in simple jig to get the nose flip, then shape deck and vac bag top. vac bagged first floppy eps surfboard blank in 1985. never have had a problem changing or keeping intented rocker under vacuum .
sorting out rail per plans
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Rails vacuumed bagged on.
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nose block/tail block
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nose block/tail block
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All sanded and Senior Prom pictures pre glass, pre glass leash bplug and pete casica gortex tent
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Charlie.....I never forget Ewa....with Diamond Head in the distance on 2nd photo behind the gate!! Had many go outs there in the hood...with not another surfer in sight. Fond memories.
Amen brother. The mile out reef at the 6 foot depth is surfer magazine centerfold perfection. When my wife paddles out it doubles the crowd.
Pray all is well.
warmest aloha
Charlie
final glassin, filler coat, urethane spray and polish to 1000 grit
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Very nice, very John Galera-influenced. Keep us posted on how it works, please
doc....
Doc,
I'm not familiar with the work of John Galera. Any similarity is coincidental. The channel design is phyics based.
Unfortunately, the soonest I might be able to test it is next summer (CoVid grounded). Besides, I'm too old to be a credible test pilot.
Happy to send you a channel insert ("cartridge") for testing.
Bill
Swaylocks Surfboard Design Forum: thoughts & theories ... practical & theoretical
RAIL PROFILE http://bgboard.blogspot.com/2014/03/march-82014-afterr-seeing-recent.html
Charlie's build is the first complete prototype of my channel project. Shaped, veneered and glassed with Charlie's "wizardry.” A work of Art!
The CAD and CNC cutting "magic," for the bottom channel as well as planshape and nose-rocker templates, are the work of Jim (jrandy).
The physics, math and design -- bottom channel, planshape, nose rocker -- are my work. I filed a patent application for the bottom-channel design in 2019. I did this to protect myself from the large commercial board manufacturers.
Below are my favorite CAD graphic that Jim created from my design data and me displaying Charlie's sculpture shortly after I received it.
BB_Meshlab.png
BB_48a_6.jpg
BB_48b_6.jpg
Swaylocks Surfboard Design Forum: thoughts & theories ... practical & theoretical
RAIL PROFILE http://bgboard.blogspot.com/2014/03/march-82014-afterr-seeing-recent.html
Hi Bill,
Just chuckling- we 'alternative forms' guys do look alike.
And good- while the numbers might not be big enough to pay fpr patent defence in court, still, it'll slow them down some.
Wow, while I'd love to play with it, between the virus and age and infirmity I would be the world's worst test pilot. Plus my access to CAD/CAM equipment is limited, my cousin has a lovely setup but he's working with metal, small production runs of things like firearms parts. Really, really nice firearms parts, though.
In any event, yeah, John Galera- see https://mypaipoboards.org/interviews/JohnGalera/JG_2009-0922.shtml
Doc, I bought this Galera board from Bob Green in Queensland, Australia and rode it until a year ago.The bigger the wave the better it rode as the deep channel needed a lot of water to function.
I expect it will be the same with this cool looking missile from BB30 and Bill.
BB30, that's some great laminate vacuuming !
D4E1260C-B82C-42E3-87D0-467E8A284440.jpeg
(chuckling) Bob is on here, he and I have been corresponding for years about paipos, life, the universe and everything. Great guy.
I have always been curious about the Galera model, the very curved bottom always had me wondering how it would hold an edge on a steep section. Could you ( or Bob) chime in on that?
Many thanks
doc...
Gday Doc,
I probably dropped off the latest e-mail chain we had and have been sleeping on the job on this thread (aka my attention has been focussed elsewhere lately).
A word about John Galera - I owe him a debt for sending me one of his paipo boards in 2004 which has sent me on a trajectory of experimenting with all manner of bellyboards.
John's boards are meant to be ridden in Hawaiian surf. Here is some footage of John https://www.youtube.com/watch?v=BJT3AwuENdg from a small website project: http://home.brisnet.org.au/~bgreen/HawaiiPaipo/HawaiiPaipo.shtml
These boards hold an edge in steep hollow waves. As with the current boards I ride, the single biggest problem is going fast from a hollow section to a full, flatter section where you have to regain an edge. In the footage where John is sliding down the face, this looks more to be a product of being where the lip impacts. The bounce on the first wave is something experienced when riding bellyboards and the shock isn't absorbed in the same way a stand-up surfer can absorb this force.
Regarding the current board, my initial reaction is that the tail channels look too bulky. However, having said that, it depends on what type of wave is intended to be ridden and what experience is sought. I've ridden boards people have raved about and not felt the same way. I also tend to like more curved lines (I can see how this can go wrong as I type) .
However, the only really proof is in how it rides. Great workmanship there.
Bob
Deleted. Wrong place.
Swaylocks Surfboard Design Forum: thoughts & theories ... practical & theoretical
RAIL PROFILE http://bgboard.blogspot.com/2014/03/march-82014-afterr-seeing-recent.html
Charlie’s skills and craftsmanship are undeniable. I really like Charlie’s interpretation of my suggested rail shape.
I encourage Jim (jrandy) to take a bow. His CAD and computer shaping of the channel and planshape templates were a significant part of the project. Jim was able to do what standard surfboard shaping software/shaping machines could not.
It took 3 people to give this prototype bodyboard its final physical form.
Swaylocks Surfboard Design Forum: thoughts & theories ... practical & theoretical
RAIL PROFILE http://bgboard.blogspot.com/2014/03/march-82014-afterr-seeing-recent.html
Thanks for the shout-out. I am happy to see the whole thing come together and glad I could be a part of it.
http://pushheretosavealife.com/ Be safe, have fun. -J
this build thread ans folloing dicussion is rad, make me pumped to get into the two belly boards i have half shapped in the shed, two edge railed beasts, inspired by greenough.
@reclaim_surf formerly Skatement
(Adam) Sunshine Coast Queensland Australia
This thread is just chucked full of Talent and Skill. Charlie brought it to life. Cool collaboration between Bill and Jim. Design and program. Fantastic guys! My hat is off to the genius in this. Much respect gentlemen. Lowel
That which can be assorted without evidence was read in an illegal magazine.
I have to agree with everything that's been said about the talent that's gone into this creation.
But just curious about what it's supposed to do?
The physics suggest the channel will create an area of low (negative) pressure under the tail. The drag should be low. The expected performance advantage would be improved tracking and directional control, without fins.
Swaylocks Surfboard Design Forum: thoughts & theories ... practical & theoretical
RAIL PROFILE http://bgboard.blogspot.com/2014/03/march-82014-afterr-seeing-recent.html
Charlie is the builder. So he will need to confirm my response.
I do not believe a rocker table was used. We went minimalist. I don't believe there is any deck rocker (deck is flat).
Tail rocker is indirect in the form of the channel bottom. Nose rocker (kick) was cut/shaped into the front third of the blank.
Swaylocks Surfboard Design Forum: thoughts & theories ... practical & theoretical
RAIL PROFILE http://bgboard.blogspot.com/2014/03/march-82014-afterr-seeing-recent.html
The channel design has some very specific curves and dimensions. It would be very time consuming and difficult to precisely shape it by hand.
Jim computer shaped my design -- to hundredths of an inch -- as a panel that can be grafted into a blank of any shape. Jim called it a cartridge, now referred to as a "channel cartridge."
The smaller size of the channel cartridge facilitates more cost effective shipping from MN to HI, KY or anywhere else. This allows us to send it to test pilot/shapers.
Swaylocks Surfboard Design Forum: thoughts & theories ... practical & theoretical
RAIL PROFILE http://bgboard.blogspot.com/2014/03/march-82014-afterr-seeing-recent.html
The more I see, the more I like.
Now, given a set of fixed dimensions for the cartridge, wondering if you've got an ideal planing area mapped out to work with it? Or is that part of the testing? Thinking about experimental design: if the cartridge was made up as, say, a waterproof subassembly ( completely surfaced, glassed, etc) that could be swapped in and out of several different boards with varying characteristics you could get some great data. I'm sure you can picture what I'm thinking about.
Thanks, looking forward to how this works and develops.
doc....
Wow! Very cool board. Glad you found somebody with the talent to do your project, Bill. It came out incredible. Mike
Doc,
You are at the trailhead now. But the number of divergent trail choices at the outset is enormous.
Early on, I considered interchangeable channels. But I couldn't even find somebody to computer shape a foam channel. I had done a couple of projects with Jim before. So when traditional surfboard shaping software/machines were a bust, I went to my garage CNC/CAM magician, Jim. Bottom line, it was clear that the complexity of Interchangeable channels meant real world protypes were well beyond reach in the immediate future.
The number of variable combinations is immense. I used the SWAG method to determine the initial channel dimensions. The first channel was designed for a 42" BB. Then using the SWAG method, I designed a channel for a 48" BB. I sent Charlie both. He chose to build the 48" BB first.
I'm still not convinced the current dimensions are optimum. All of my curves are defined by equations. I can adjust them for any combination of dimensions desired. One-offs are doable if Jim has time outside his day job.
At the moment, my belief is the planing area around the channel is most critical -- referred to as the tail "pontoons." But I do not know what the "optimum" channel dimensions are. I suspect there is a desirable low/negative pressure -- too high or low diminishes performance. This will be affected by velocity.
I tried to recruit several Sways shaper test pilots. By dumb luck and pure good fortune Charlie was the first Sways adept to shape a board.
We still have no test pilots. As offered previously, if Jim has the time, I am happy to work with him to make and ship you some graftable foam "channel cartridges."
The channel is intended for use in several types of surfcraft. However, the original objective was to improve BB tracking without fins. I'm liking the idea of a "Finless Fish" somewhere in the near future. But I think it could be used effectively in combination with a twin-fin set up (quads?).
Bill
BTW for those not familiar with the jargon, SWAG = Scientific Wild Ass Guess.
Swaylocks Surfboard Design Forum: thoughts & theories ... practical & theoretical
RAIL PROFILE http://bgboard.blogspot.com/2014/03/march-82014-afterr-seeing-recent.html
Hi Bill,
Right? There's a few ways to make a swappable cartridge, I think, fairly straightforward, but for the moment .... and it's real nice to see a SWAG in this field, the vast majority of 'surf science' is what a friend of mine described as 'hand waving and hope'. I come from a marine engineering/naval architecture background-we like numbers.
Measuring things is the key, and difficult- waves are inconsistent, speed through the water is easy enough in a tank test but speed, say, versus angle of attack on a 3D curved moving surface? Owning, say, your very own wave pool or some river you could play with to make a standing wave?
In any event, yeah, I suspect the ratio of area of the pontoons ( or, if you like, steal the term 'sponsons' from the planing surfaces on racing hydroplane boats) to the channel volume, say, is important. Or, perhaps, the bottom surface actually in contact with the water at a given speed? The volume could be measured, mask it off and pour in water maybe, but given the consistent shape of the channel I'll bet the area of the back end of it would be good enough. The width versus the height too, that ratio, but that's a whole other thing. As you say, the sheaf of options is enormous. Spreads out like a peacock's tail ( or, considering the date, a turkey's)
Which has me thinking about maybe model testing? To narrow that spread? If a fairly fast-flowing stream (or for that matter any reasonably deep flowing system) was available? Foam, or for that matter painted wood, models scaled down accurately, measure drag, measure resistance to sideways force, measure force exerted when the angle it pointed was changed? While test pilots/actual use would give you a very general idea of desirable characteristics, this model testing might be a real good way to fine those down quickly and inexpensively/easily?
Fascinating stuff
doc...
Doc,
Don't have time for an expanded response at the moment. Maybe later when I have more time to mull over my words. Gotta get in a fill coat before dinner -- my weather window is closing quickly.
Between the two of us, we have barely identified the tip of an iceberg. I see at least two graduate thesis projects in what we have discussed so far.
I have a broad-base undergraduate science background. I am a retired scientist, graduate education ranged from medical science to aquatic science. My professional research would fall under the broad topic of aquatic science.
My rabbit hole for this channel project, curves in two dimensions and depth...
Bill
Swaylocks Surfboard Design Forum: thoughts & theories ... practical & theoretical
RAIL PROFILE http://bgboard.blogspot.com/2014/03/march-82014-afterr-seeing-recent.html
(chuckling) Ya think? The real trick is in writing the grant applications to fund all of this R&D plus a few beers.
Times like this I especially miss Terry Hendricks. He had, among many other things,. a real gift for devising nice and inexpensive ways to test things.
Modelling hulls and hydrodynamics, numerically, well, they used Crays to do America's Cup boats in flat water a decade or two ago. Million dollar plus project. Computing power and the cost of it have changed a lot since then but modelling a surfcraft on a moving wave I would estimate to be orders of magnitude more number crunching, would have to get a good basis/basic data to work from to begin with. Maybe the Navy has something like that for hull design, I do know I couldn't even attempt to write the software on the best day I ever had.
Glad you reminded me, they're giving rain for tonight and I have to get a tarp over something I won't get to installing or moving in the dark. Back to earth, as it were.
doc....
My initial fear would be that the first prototype is the 48" and not the 42", That is a very big/floaty "bodyboard" and will be a handful in its self, which I think will make it hard to derive if the channel design is working because of the fight I think the size of the board will put up.
slater tried out a similar concept with Merrick, their design had a hole through to the deck to allow air from the top into the channel.
https://www.cisurfboards.com/2010/kelly-slaters-latest-experiment-the-ch...
As I come from the 'potato chip (or 'crisp', depending onm where you are) era of paipo boards, I'm kinda along with you on this. The good news is that what with the CAD/CAM aspect of the channel shaping, scaling it becomes trivial. Really, it's all about planing area, buoyancy doesn't really help one way or the other when it's that size.
I hadn't seen the Merrick/Slater project, I recall one from the '70s that had an air scoop forward, air channels in the foam and a series of transverse depressions in the otherwise flat bottom. The idea, as I understood it then, was to make an air layer between the bottom of the board and the water, leading to a helluva lot less friction/drag and so much higher speeds. The guys associated with it- Aipa, Barry K. and others, if memory serves - were pretty good but nothing really came of it, no idea why or why not. A wild guess would be a combination of not enough airflow and once that was sorted, controllability issues. Similar to a hovercraft in a crosswind -
Really, though, the field is wide open.
doc...
On a bodyboard if you have a wide board that has a lot of rail volume it slips out, a less buoyant knifey rail can sink it in easier and not pop out of the wave face and side slip.
I have an old fat bodyboard that I use as a groveler and have taken it on trips to g-land out of interest. Over shoulder high it is a lot harder to sink the fat rail and keep from losing the edge. My performance bodyboard is 42" and my fat groveler is 42".
Also that board may also have problems holding a rail if the bottom to rail is a hard edge. it needs to be at least a 16th round over. My glasser put a hard edge there once on a paipo of mine and (through the water release would slip very easily) rounded it over with sandpaper myself and the grip was back.
I wonder if you could make a test version of this out of an old bodyboard pretty easily just cut your channel outline in the bottom slick peal that bit up, shape out the foam below and then glue the slick back down and a couple of filler pieces.
Right? I dunno if it's the buoyancy of the rail so much as the additional planing area of the fat rail itself lifting it out of the water and the way it holds goes all to hell.
I'm a firm believer in thin boards, considering what I started out with that''s no surprise- Newport Paipo Concave Vector
doc...
Nodding in agreement with a slight chortle... no sh!t.
Swaylocks Surfboard Design Forum: thoughts & theories ... practical & theoretical
RAIL PROFILE http://bgboard.blogspot.com/2014/03/march-82014-afterr-seeing-recent.html
A fine spray of coffee descends, followed by a loud guffaw
Exactly.
And I haven't solved a calculus problem since autumn of 1972...
Swaylocks Surfboard Design Forum: thoughts & theories ... practical & theoretical
RAIL PROFILE http://bgboard.blogspot.com/2014/03/march-82014-afterr-seeing-recent.html
I tutored, likely as some sort of penance for my many and varied sins, college level maths, physics and chemistry in the '80s and with me in my 30s, already showing signs of senility , as a retread returning engineering undergrad. Including calculus. Having a memory with a retention ability akin to the water holding qualities of chicken wire, it was good to review and reinforce that stuff as otherwise I would have forgotten it before the echoes died in the lecture hall.
That was, though, at least three decades back. These days, I find myself challenged by problems like
3X+1=10. Solve for X.
A ladyfriend's high school daugher has, unsurprisingly, an algebra class, and her mother emails me the more annoying word problems under the sadly mistaken belief I can be useful. Heaven help me when she gets to Geometry, though if she's relying on my help to advance that's rather unlikely to happen.
x=3.33?
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