Larry G is Larry Goddard -
See http://mypaipoboards.org/interviews/LarryGoddard/LarryGoddard.shtml
Bob
BUMPED UP FOR NEW FORUM MEMBERS. For best results, and understanding, read from the beginning.
Thanks! But now my head hurts! LOL!
Physics and Algebra. Civil dialogue. The Golden Era of Sways.
This may get exiled to a science only sub-forum.
Lol! physics and MATH!..PFFT!..there’s an app for that!
https://www.youtube.com/watch?v=xrhVJ6ruXpQ#t=107
duplicate
Taking it to the max: Even recording EEG during a surf session!
Hopefully I have caught all of the typos.
The upper limit speed of a surfer/surfboard on a wave is a simple calculation. This upper limit speed assumes no drag/friction or upward movement of water in the wave face. Actual maximum surfing speed would be slower.
The calculation is simple high school physics and algebra. Maximum surfing speed cannot be greater than the free-fall speed (Vmax) of a surfer falling from a height equal to the height of the wave.
Vmax = square root of 2gh
where
g = gravity (32 ft/sec^2 or 9.8 m/sec^2)
h = height (in this case wave height)
The first table at the bottom of the post shows the upper limit, free-fall, surfing speeds for several wave heights (assuming no friction and no upward movement of water in the wave face.)
The minimum surfing speed cannot be less than the wave speed (C). Surfable waves are shallow water waves. Approximate wave speed can be calculated with the following equation.
C = square root of dg
where
d = depth
g = gravity (32 ft/sec^2 or 9.8 m/sec^2)
Water depth for breaking waves depends on wave types (Galvin, 1968; J. Geophys. Res.)
For plunging waves, d = 0.9h
For spilling waves, d = 1.2h
Where
d = water depth
h = wave height
(Speeds for several heights of plunging and spilling waves are shown in the tables at the bottom of this post.)
The maximum angle of surfboard travel (A) relative the direction of wave travel is determined by the maximum surfing speed.
CosA = wave speed (C) divided by maximum surfing speed (Vmax)
CosA = C/Vmax
Assuming no friction or upward water movement in the wave face, (using high school trigonometry) approximate maximum values of angle A would be;
48 degrees for plunging waves,
and
39 degrees for spilling waves.
The form of surfing waves will range from plunging to spilling.
Maximum speed of a surfer at the bottom of a wave (curved ramp/inclined plane) cannot be faster than free-fall speed.
I’m not trying to fault your maths, but it seems that there are two components of speed. the first is resultant speed of the surfer in the direction of the wave. The second is the speed with which the surfer traverses the wave face. It would seem that the resultant vector would be longer than just the speed in the direction of the wave. I’m happy to be convinced otherwise.
https://www.surfertoday.com/surfing/5126-top-surfers-check-speed-and-distance-in-a-wave
“In Snapper Rocks, Mick Fanning is currently the fastest surfer. The Australian champion recorded a maximum speed of 39,1 km/h. In second place, Joel Parkinson stands with 34,6 km/h. Bede Durbidge is third (33,6 km/h) and 10-time world champion Kelly Slater places in fourth (32 km/h).”
The numbers in Imperial are 24.3; 21.5; 20.9; 19.9 mph which match well with your estimations for one vector.
Don’t know which day they measured speeds in the article, but the surf looked to be in the 4-6’ range http://www.worldsurfleague.com/posts/16096/round-4-and-5-highlights-2011-quiksilver-pro-australia?serializedFilterBy=e235
I meant to reply to Stoneburners post Nr 88, not Nr 89.
Stoneburner, I think your conclusion is wrong: The maximum attainable surfing speed on a wave is not limited by the free fall speed that would be attained when falling the height of the waves face.
https://www.angio.net/personal/climb/speed.html
I have measured a top speed of about 45km/h surfing waves with faces around 3-4m high, but according to your hypothesis, the waves would have had to have 8m faces.
Absolutly correct.
MrMik, if you’ve measured yourself at 45 kph and Fanning is formally clocked at 39 kph.
How did you get 15% faster than a 3X world champion Mick Fanning and Joel Parkinson too ?
just asking how you are faster. Was it the single fin ?
Question , where are the tracking devices , on the surfer or on the surfboard , are speeds being measured that of the surfer or the surfboard ? Yes I know that the surfer is standing on the surfboard but on a cut back or bottom turn for instance the surfer will not travel as far or as fast as the surfboard .
Most impressive to be sure Brett.
I did not say that maximum surfing speed is “limited by the free-fall speed” Mr. M. I said it “cannot be faster than free-fall speed.”
It may help to review the physics of inclined planes and curved ramps.
Gravity is the driving force.
Agreed. Vmax is that long velocity vector that allows the surfer to travel forward at wave speed (C) while traveling perpendicular to the direction of wave motion at transverse velocity (Vtrans).
I have no doubt you are aware that trigonometry is based on the geometry of right triangles. Vmax is the hypotenuse of that right triangle and C is the side adjacent to angle A (39-48 degrees). Vtrans is the side opposite angle A. Vtrans can be calculated using SinA (39-48 degrees).
SinA = Vtrans/Vmax
Sin 39 degrees = 0.629
Vtrans = 0.629 x Vmax
Sin 48 degrees = 0.743
Vtrans = 0.743 x Vmax
For a 25-foot wave, plunging or spilling, Vmax = 27.2 mph.
For a 25-ft plunging wave,
Vtrans = 20.2 mph
For a 25-ft spilling wave,
Vtrans = 17.1 mph
I will try to put together a vector figure later this evening.
Is the human power train taken into consideration as a factor to increase max speed?
Because, just that one year in 2011, I did not participate in the Quiccky Pro. HAHA!
Of course it depends on wave size, and when I surfed my 7’11’’ single fin Nugget and got fast, it was at the tail end of a big cyclone swell.
I rest my case.
You are confusing yourself with too much complex maths, when the facts are so obviously testifying against your postulate. Fascinating.
Gravity is part of the equation, but the the energy transmitted in the wave is the driving force.
I don’t know how they measured speed of the surfers at the competition.
In my case, it’s measured by a Trace mounted to the nose of the board. I found it produces believable and reproducible results.
