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.
great question. In mass production the simple solution would be to glass, cnc or replicate cut and glass cut out section.
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 .
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.
Not sure what you mean by “too bulky.”
Agreed the important assessment will be the qualitative comparison to what is out there. And what you like.
The objective is low drag, improved tracking/control – without fins.
The channel could be used in any shape.
Bill
By bulky I mean thick. Attached is a photo looking down from the tail of my favourite board - it is number 7 in a series, refining an original design of Larry Goddard.
What is your thickness?
Tail thickness is determined by channel depth which is not a fixed constant. Or vice versa…
x=3.33?
It’s hard to measure, probably 1/4" on wing and 1/2" at tail, flatter section, but it is a curve, so tricky to be exact.
This photo is of a board from John Galera.
I’m off to work now, happy to chat later.
So far, the Galera boards I have seen use linear channels.
Yes, like pontoons, with the foam scooped out down the centre, which is fibreglass like a spoon.
3.66
3X-1=10
add one to both sides
3X=10+1
divide both sides by three
X=11/3 or 3 2/3 or 3.6666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666 infinitely repeating
And now you understand my problems. Problems plural 'cos first I had to go through such things myself for the kid and second I meant to and didn’t write the original equation as
3X + 1 = 10,
senility strikes again.
doc…
I suppose it would be possible to shape a "“torso/chest well” into the deck to decrease thickness overall. And add belly to the nose for further thinning.
It is likely the channel effect will require riding weight forward to trim.
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-chunnel/
From someone who may have never have solved a calculus problem (Doc I’ll be contacting you for tuition. Your website tuition was much appreciated, only joking about the maths) I have a simpler alternative to the grants application, though in covid times it could be problematic. A Swaylocks travel board. Another gets made, share it around and notes get taken and compared. I know Krusher likes shorter boards, 48" seems ok by me.
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…
Ummmm- Bob, there’s the thing: given a channel with dimensions A through Z, set in a particular board with dimensions a through z, you just learn whether or not that particular board works, and why it works or doesn’t work is a whole 'nother animal, let alone whether or not the concept works.
That’s where Stonebreaker’s idea of shipping precision computer cut channel; cartridges (say that a few times fast ) comes in. You put one in anything you like, new large bodyboard-like paipo to retrofitted klunker longboard and anything that turns your fancy, see what it does, get back to the rest of us with that . And we analyse, learn, change, adapt and go onwards,
Oh, and being me, had a look, your coding is coming along nicely. `You’re a credit to your teacher -
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.