Surfing Waves

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you like that fin dont you!

is there any reason why we should want to watch you wandering round your board in a workshop?

surferdude_scarborough wrote:is there any reason why we should want to watch you wandering round your board in a workshop?

That depends upon whether or not you are a really dedicated surfer . . . as a really keen surfer I must say that I enjoy seeing any and every kind of surfing video . . . and did you realise that the seventeen foot parallel profile surfboard in that video is unique in the world?
No one else does them like that, period. Didn't you find the interplay of curves on that board interesting? As the builder, I have walked around that board countless times during the 200 plus hours which it took to build it and the 100 hours or so spent rebuilding it after it broke, and I still find the curves fascinating.
Surely you can see how delicate, and almost dainty looking this 60 pound, 17 foot redwood board is? Did you notice the beautiful swoop which the deck has as it follows the bottom curve exactly? If you did, realise that you are looking at something unique, functional, and beautiful.

Open your eyes and ears!

.

RoyStewart wrote:

surferdude_scarborough wrote:is there any reason why we should want to watch you wandering round your board in a workshop?

That depends upon whether or not you are a really dedicated surfer . . . as a really keen surfer I must say that I enjoy seeing any and every kind of surfing video . . . and did you realise that the seventeen foot parallel profile surfboard in that video is unique in the world?
No one else does them like that, period. Didn't you find the interplay of curves on that board interesting? As the builder, I have walked around that board countless times during the 200 plus hours which it took to build it and the 100 hours or so spent rebuilding it after it broke, and I still find the curves fascinating.
Surely you can see how delicate, and almost dainty looking this 60 pound, 17 foot redwood board is? Did you notice the beautiful swoop which the deck has as it follows the bottom curve exactly? If you did, realise that you are looking at something unique, functional, and beautiful.

Open your eyes and ears!

.

You sure love to toot your own horn dont you big roy?

point and laugh

gulfsurfer wrote:

RoyStewart wrote:

surferdude_scarborough wrote:is there any reason why we should want to watch you wandering round your board in a workshop?

That depends upon whether or not you are a really dedicated surfer . . . as a really keen surfer I must say that I enjoy seeing any and every kind of surfing video . . . and did you realise that the seventeen foot parallel profile surfboard in that video is unique in the world?
No one else does them like that, period. Didn't you find the interplay of curves on that board interesting? As the builder, I have walked around that board countless times during the 200 plus hours which it took to build it and the 100 hours or so spent rebuilding it after it broke, and I still find the curves fascinating.
Surely you can see how delicate, and almost dainty looking this 60 pound, 17 foot redwood board is? Did you notice the beautiful swoop which the deck has as it follows the bottom curve exactly? If you did, realise that you are looking at something unique, functional, and beautiful.

Open your eyes and ears!

.

You sure love to toot your own horn dont you big roy?

point and laugh

Yeah, why not? Like I said before, God created everything, and thus anything good which is produced by myself is by God's grace and inspiration.

Celebrating the creation of a board is a perfectly holy thing to do . . all really dedicated board builders do it, but not always publicly.

i liked the tail roy, it looked nice, and quite odd, almost like the back of a canoe, like upright, what effect does this have on the way the board rides?
and what is the effect of that fin?
i also noticed the board seems to have a lot of rocker, (piecing information together here so please tell me if this is wrong) do flatter boards plane better? except id think this board would glide pretty well, does it just look like a lot of rocker because of the camera angle and length? if not what effect does this have?
(sorry everybody-budding shaper here im collecting information)

RoyStewart wrote:

gulfsurfer wrote:

RoyStewart wrote:

surferdude_scarborough wrote:is there any reason why we should want to watch you wandering round your board in a workshop?

That depends upon whether or not you are a really dedicated surfer . . . as a really keen surfer I must say that I enjoy seeing any and every kind of surfing video . . . and did you realise that the seventeen foot parallel profile surfboard in that video is unique in the world?
No one else does them like that, period. Didn't you find the interplay of curves on that board interesting? As the builder, I have walked around that board countless times during the 200 plus hours which it took to build it and the 100 hours or so spent rebuilding it after it broke, and I still find the curves fascinating.
Surely you can see how delicate, and almost dainty looking this 60 pound, 17 foot redwood board is? Did you notice the beautiful swoop which the deck has as it follows the bottom curve exactly? If you did, realise that you are looking at something unique, functional, and beautiful.

Open your eyes and ears!

.

You sure love to toot your own horn dont you big roy?

point and laugh

Yeah, why not? Like I said before, God created everything, and thus anything good which is produced by myself is by God's grace and inspiration.

Celebrating the creation of a board is a perfectly holy thing to do . . all really dedicated board builders do it, but not always publicly.

Ok, "God"

Here's one for you gulfsurf:

"Power Surfboards are for those who want to admire the view. . .
Other surfboards are for those who want the view to admire them!"


( The truth content of the above statement is estimated by the author to be approximately 65%. )

Dude, is there some f u c k i n g reason why you always have to make everyone think you are right??
first of all, you wear a pink wetsuit, thats just gay man.
2nd, your "longboards" are 21 feet long and look like a gun.
3rd, you're a weird basterd.
and 4th, you think that anything except what you do is "dysfunctional"

gulfsurfer wrote:Dude, is there some f u c k i n g reason why you always have to make everyone think you are right??
first of all, you wear a pink wetsuit, thats just gay man.
2nd, your "longboards" are 21 feet long and look like a gun.
3rd, you're a weird basterd.
and 4th, you think that anything except what you do is "dysfunctional"

Gulfsurfer, I prefer to discuss hydrodynamics and surfboard design, and if you say something sensible I will be keen to agree with you.

Thankyou for your comments regarding my boards, wetsuits, ancestry, and sanity. They have been processed and evaluated.

Good day to you.

Gulfsurfer; walk away dude. The driveway doesn't quite reach the garage door if you know what I mean...*smirk*

babyboarder89 wrote:i liked the tail roy, it looked nice, and quite odd, almost like the back of a canoe, like upright, what effect does this have on the way the board rides?
and what is the effect of that fin?
i also noticed the board seems to have a lot of rocker, (piecing information together here so please tell me if this is wrong) do flatter boards plane better? except id think this board would glide pretty well, does it just look like a lot of rocker because of the camera angle and length? if not what effect does this have?
(sorry everybody-budding shaper here im collecting information)

I prefer to discuss hydrodynamics and surfboard design

yes im hinting.

Hi Baby boarder. Please excuse me for not replying sooner.

The tail of the 17 footer is what we call an extreme pintail because it is defined by two circular arc tail sections in planshape (which start at the widepoint in planshape). This kind of tail gives a more extreme pin than a tail drawn using elliptical or other accelerating curves.
When you say that the tail looked upright I assume that you are noticing the vertical facet made where the semi circular rail sections intersect. This vertical facet is an inevitable result of the continuous rail section which is used on the board, and it has some useful characteristics.
In talking about the use which this vertical facet on the tail has, it will help to see how the extreme pintail behaves, (and in partcular, how an extreme pintail on a parallel profile, constant rail section board works)
The extreme pintail is a tail shape which allows the water a clean and free flowing exit from the tail under all possible circumstances. Whether the extreme pintail has to run immersed, or whether it runs on top of the water, the result is that the tail offers a clean exit. The tail of a surfboard may be thought of as similar to the trailing edge of a fin, (particularly if that tail is occasionally fully immersed) and if it is thought of in this way, it can be seen that the same advantages which are gained by having a constant circular trailing arc for the fin foil section are able to be gained by the surfboard tail itself: namely low drag and a clean water flow exit.
A non circular arc tail necessarily has an accelerating tail curve which can cause drag. This is why fins do not have accelerating curves through the trailing part of the fin cross section.

More about this in a few minutes time.

The extreme pintail, because it is so narrow, is able to be sunk during (relatively) tight turns without stalling ( and without much drag ). This helps with control by effectively shortening the turning arc and also because the rider can more easily lift the nose when necessary if he can sink the tail.

The small vertical facet which you noticed at the tail actually, when the tail is sunk, becomes like the tip of a fin, and won't stall in this situation

The extreme pitail also hangs into the wave like nothing else and gives amazingly precise control at speed.

With very large boards one has so much area available already that the designer has the luxury of being able to draw the board out finely at the tail.


Over to you:

so the tail makes it turn better?
what is an accelerating curve?
and how anout the rocker and the fin?
sorry for so many questions, im intruiged.

RoyStewart wrote:

gulfsurfer wrote:Dude, is there some f u c k i n g reason why you always have to make everyone think you are right??
first of all, you wear a pink wetsuit, thats just gay man.
2nd, your "longboards" are 21 feet long and look like a gun.
3rd, you're a weird basterd.
and 4th, you think that anything except what you do is "dysfunctional"

Gulfsurfer, I prefer to discuss hydrodynamics and surfboard design, and if you say something sensible I will be keen to agree with you.

Thankyou for your comments regarding my boards, wetsuits, ancestry, and sanity. They have been processed and evaluated.

Good day to you.

what wasnt sensible?
i dont think you are very sensible either.

An accelerating curve is one where the rate of curvature increases. Roundtails are examples of planshapes drawn with accelerating curves. An ellipse is an accelerating curve.

As for turning 'better', the extreme pintail is not an ideal solution for turning a 6 footer, (because you would lose a lot of planing area that way) but it is very useful for bigger boards (9 feet plus)

By drawing the tail shape with a circular arc you avoid having parallel or nearly parallel rails. Parallel rails inhibit turning, and that is why longboards with fairly parallel rails can't be turned effectively from the middle of the board.
With a very long board, it is important to make turning as easy as is possible by introducing as much planshape curve as possible,right from the wide point aft. That way you can turn the board from the middle.
The only way to get the maximum effective turning curve in the rail from the middle of the board aft is to draw a circular arc ending in a pintail. Every other possible curve will create rails which are closer to parallel in the middle of the board than is possible.

The extreme pintail has other useful qualities. One of these is that it is excellent both as a tail for a planing hull and as a low drag exit for a displacement hull. A board like the 17 foot Star Board has a good paddling speed, and a high diplacement hull speed. Sometimes on slow sections the board will ride the wave as a displacement (non planing) hull, and then it will accelerate onto the plane. Pintails give a smooth transition from displacement speeds (whether this is during paddle in, takeoff, or riding a slow section) without the 'bump' or sudden increase in drag during the tansition which is a characteristic of typical wide tailed planing hulls.

As I mentioned previously, surfboard tails (longboard tails in particular) sometimes actually run underwater (E.g. when a wave breaks on the tail). When this happens to a wide tailed board, the water pressure on the wide flat surface inhibits rail to rail movement.. . .and the board becomes 'locked in' and hard to turn. This is what happens to wide tailed noseriding boards. I believe that it is a good idea to design really big boards which are able to be turned at all times and in all circumstances . . the surfer must be able to control his board! By using a pintail, we find that in the situation just mentioned (the wave breaking on the tail of the board) the board is able to roll rail to rail and maintain control even when the tail is underwater. Also the tail in that situation maintains a clean exit and does not interrupt the water flow even when rolling rail to rail.

Rocker and fin stuff later today

Thanks for your interest!

thankyou for your answers

Thanks for your PM reminding me about your rocker and fin questions. I have been busy teaching but am now free again to delve into surfboard design.

The Rocker on the Seventeen footer:

As you have noticed, the rocker on the 17 footer appears to be very pronounced when the board is viewed from the nose or tail. The total amount of rocker in the board is ten inches, which again seems to be a lot.
With very long boards, more overall rocker is necessary if the board is going to surf hollow waves. Paradoxically though, the overall rocker mesurement in a board is not a true indication of the amount of rocker on a curvature per foot basis. Thus, even though the rocker on a very long board will appear to be large, the actual measurement in terms of inches of curvature per foot is often less than that found on shorter apparently less rockered boards.
To illustrate this point, if the seventeen footer were cut in half at the rocker apex (in this case the mid point of the board)then the rocker in each of the two 8 foot 6 inch sections would only be about 2 inches. . . which is rather flat for an eight footer.
Thus it can be seen that ten inches of rocker on a seventeen foot board is actually a very moderate curve, and is even on the flat side for an all round board intended for surfing hollow sections.

Because board builders have (historically) measured rocker as an overall measurement, they have tended to assume that longer boards need more rocker in proportion to their length. This means that the tendency has been to use twice as much rocker (in terms of an overall measurement) on a board which is twice as long. . . .or at least to assume that by doing so they are achieving the same rocker curve in both boards.
In fact, a board with 2 inches of rocker over 8 feet, will, (as I have just mentioned) if extrapolated to twice that length,actually have far more than four inches of rocker.
It is the the amount of rocker per foot which is the important yardstick . . .not the overall rocker measurement. This is because it is the actual rate of board curvature which has to be matched with the actual rate of wave curvature, regardless of the length of the board.

Another reason why very long boards are typically not highly rockered is that the ancient Olo boards and hollowpaddleboards were fairly flat.
Recently I have been comparing notes with Tom Wegener, who is building 16 footes based quite closely on King Paki's 16 foot Olo board. Tom's boards are rather flat in the rocker compared with mine. The result is that his boards paddle faster, catch flatter waves earlier, and ride unbroken swells more efficiently than my 17 footers. They are, however, not suitable for general surfing and riding hollow sections. In comparison, my 17 will handle hollow waves better, turn much more tightly, and turn more easily in hollow waves. My 17 still rides unbroken swells nicely, paddles very well, and catches waves early, so I feel that the board is an excellent compromise rocker wise. Tom's OLO replica is on the flatter side of the rocker range, and is thus optimised for unbroken swell riding.

If you are interested in the rocker distribution on the 17 footer (the actual shape of the rocker) and alternative rocker shapes, then please just sing out nice and loudly!

In the meantime please let me know if I have been unclear in any way.

Till next time

Roy

PS (No doubt Brent and Gulfsurfer will relish the idea of cutting my 17 in half, but they will not live to see it happen!)