Wakesurf Debate? What is PUSH?
 

I have heard people say that push doesn't exist, and I over heard someone at a recent event correcting a newer person to wakesurfing, telling them there was no such thing as push. I just think that is silly, to say the least. So instead of just arguing, I cam up with this visual demonstration to explain PUSH. Let me know what you think.

<iframe width="853" height="480" src="//www.youtube.com/embed/ppmpsnKsl7w" frameborder="0" allowfullscreen></iframe>

Einstein would be proud!! Fabric of Space .......

Nice Surfing Dude!!

That was a great demo. Thanks for sharing.

Thanks @blaze.

@frank, its funny you mention that because in the video I talked about gravity and even had a clip of Neil deGrasse Tyson (an astrophysicist) talking about the "Pull of Gravity". I edited it out to keep the video from getting even longer, but also because even though PULL is not accurate when referring to gravity, I think PUSH is fairly accurate when speaking of a wave propelling a surfer.

Neither push nor pull are accurate terms. Lift is an accurate term.
A more accurate demonstration would be taking the table cloth, putting it over smooth sand with the truck there and making indents into the sand with your hands for the truck to roll down into. This is what the boat is doing, displacing the water to make an incline for you to ride down. The water, unlike the sand, is rushing up to become level again with the rest of the water level. You are riding down that incline, but the incline is moving up towards you, very similar to those artificial ski slopes, which are basically a treadmill on an incline heading up. If there was no force moving back up at you and lifting you up, it would be just like riding your surfboard down a hill into the water. You would faceplant and sink, same thing if they shut the treadmill off with you on it.
You need the boat to create an incline (with ballast) for you to ride down into. The faster the boat goes, the shallower it digs, but the longer the pocket is, because the water can only rush back up so fast.
The wave behind you (broomstick) is just the by product of what is happening. It is not the means of what is making your motion happen.

Good surfing though. I thought you were going down the first time you started to pearl. Nice recovery.

Those are good points, valid. 2 things:

1. My main point is that PUSH is an acceptable term to use, even though some could argue it may not be the most accurate.
2. The broomstick, or the wave, is invisible energy that is moving horizontal to the wave. There IS something there (the energy) that is traveling in that direction, not just the upward movement of the water.

Think of another visual/mental experiment. Imagine you are riding a skateboard down a road and a car comes up behind you. If he is traveling too fast, you are toast. But if the car is only going a few MPH more than you can put your hands on the hood and it would PUSH you forward. I think there would be NO argument that the car is PUSHING you forward. The CAR is providing the energy that propels you, and in a VERY direct way.

Now imagine that this car is shaped like a wedge with only a 10 degree or so angle and the front of it is RIGHT on the ground, a smooth transition from the road to the incline of the wedge. Its still a car, but weird looking. It comes up behind too fast, and it may hit your wheels and barely move you forward and lift you up and over its top. If the car and you are closer in speed you would be able to use the incline and keep riding forward.

Wouldn't you say the car is still pushing you forward? It doing it in a different way, but the CAR is providing the energy to move you forward, just translating your movement in a different way.

Oh, thanks for the surfing compliment. ;-)

Good vid! I need to demo a Z3 next!!!

Correction, I meant to say, "horizontal to the WATER".

@onetogofast, Thx!

Most people can't relate to being lifted. Unless their in an elevator. The only example i can think of to demonstrate lift is the wheels on your feet while your laying on your back much like a wheelbarrow.Your still getting pushed forward by the energy[person] that is lifting you. Lifting push both terms can apply.

Great video and surfing at the end. I think your board needs a little more nose rocker in it though because you were able to PUSH the nose under the water pretty easily there! :D

@timmyb too true! I have another board, smaller, more rocker, but the tail was also changed, and it just didn't work right, so back to this one, old faithful. Also, I normally ride much farther back, but RJ made a small change in the weight and it made a huge difference in push and I couldn't stay away from the boat, just kept throwing me forward. Next up I was able to adjust my feet better to stay away. ;-) If I was more nimble I am sure I could have adjusted on the fly better.

Everybody is missing the point. Everyone knows push doesn't actually exist, including Robert. He even says so. However, he is saying push is now an acceptable term. Personally, I think it's idiotic. "Here's something called this but, I think we should call it that because the general public is too stupid to understand what is actually going on."

..and people thank him for this. :confused:

No, that is incorrect, I think PUSH is a correct term. The wave or energy, is traveling through the water, the medium, and pushing you forward.

I would like to direct everyone's attention to this video. This illustrates what is happening with the wave very well as a visual analogy.
https://www.youtube.com/watch?v=PlCMDKJ8kbE

In the video, it is of an artificial ski slope. It is basically a conveyor belt on a slope that is lifting you back upwards as you are with your body weight, technique, and gravity, going down. This motion is preventing you from going all the way forward and going off the conveyor belt. It is lifting you back up away from the earth as gravity is pulling you down.
This is the same thing that is happening when you wakesurf. When you are surfing, you can look down and see the water rushing up towards you at an angle (conveyor belt) to the crest of the wave (back wall of the ski simulator). Gravity and your body's weight distribution are what is pulling you down the incline of the water (or the incline of the slope). The balance between these two is what makes you stay in equilibrium and can surf. Too steep of a slope, and you're on your back foot to back off because you are being pulled down it by gravity too fast. Not enough of a slope and you are having to pump and use your energy and put more weight forward to go down the slope.
Boards with less of a friction coefficient and bigger boards that have more inertia or are more buoyant and sit on top of the water more naturally go down the slope faster. Same as Chevy chase with the crisco on the sled on Christmas vacation. Different rides will make you go down the slope faster than others.

How deep the boat sits and plows through the water determines the depth of the hole it digs, which determines the slopes steepness. The faster the boat leaves the area of water it is displacing, the faster the rider gets into it and has a longer pocket. This is also why more front weight makes the wake longer, the boat is digging in with a greater surface.

Also check the video of a flow rider. This works in a similar fashion as the artificial ski slope, but with water. You are on an inclined surface that you are riding down and being pushed back by water traveling upwards lifting you away from the earth's gravity pull. You can say it's pushing you up, lifting you up, whatever you want to. Push seems to be the general word that is accepted and that's fine, but people get it confused and think that the back of the wave is what's pushing you forward. It is not.
https://www.youtube.com/watch?v=M6zkHmph6Fc

Really, Robert? Are there any water monsters pushing you forward?

Heres a thought for you grammar nazi's.. Push is a acceptable term because it is a word used to communicate something. YOU KNOW what the person is talking about when they use the word PUSH therefore it is acceptable because you know what im talking about when I say it. Thats how language works ... Do you think Selfie is a correct technical term .. or is " taking a picture of your self" correct?

@fence none recently.

@phathom I have thought about those examples, and here is why I don't think they apply.

1. They are not waves. What is going on behind the boat is a wave. Watch from the air or from shore, its a wave that keeps going. Something could ride it all the way to shore if light enough or on a big enough board. There are waves in water caused by wind, and waves in water caused by displacement, a wakesurf wave is the second. Here is an interesting picture:

http://jasonrstover.files.wordpress....13/04/wake.jpg

2. In your examples, videos, the motion is only relative to the "conveyor belt". Except within that limited space, they are not traveling anywhere. While wakesurfing we travel along with the boat being propelled by the wave. Now, the wave may not be perfectly moving in the direction of the boat, more outward, but neither is the wind when sailing. Even if you were traveling at a 45 deg angle to the wind in a sailboat you would still say the wind was propelling/pushing you.

An exception to this is a "standing wave", like in a river. But that is still a wave, because even though the wave seems stationary, the water (medium) is moving so the wave is still energy/disturbance moving through a medium. And if you rode that wave, its still propelling you compared to the current.

More info on a standing wave: http://en.wikipedia.org/wiki/Standing_wave

3. Take that second video, I think it is on a cruise ship. So in that case the rider is moving forward relative to the ocean. The water he is riding is lifting him, but the ship is propelling him forward. IMHO, just like the cruise ship, the wakesurf wave is propelling you or pushing you, not just lifting you. Just because you ride down the face using gravity, doesn't take away the fact that the wave is propelling you. If it was just lifting, you would look around and never see the shore go by.

It is the NAZI part of it that spurred me to make a video. I don't care what people refer to their wave's power with, say what you want. But I saw a couple of new people be made to feel stupid when they used the word push. It is a perfectly acceptable term, IMO.

Waves in the ocean travel in a direction. Toward the shore. Waves behind a boat travel in a direction. At a angle away from the boat.You could have pressured water spraying upward to create lift. Which would overcome gravity and keep you above the water level. Without the movement of either wave[ ocean or boat ] you wouldn't be able to recover from your loss of lift. Therefore you need both lift and forward movement [push] of the wave.

Let me put it this way. You are definitely riding the wave, however you are riding down the face of the wave. Now in actual surfing, that wave is moving towards the beach, you are moving along with it, but all the time riding down the face of it. You never see anyone on the top of the wave, because if they were, they would be riding down the back of it as if it just passed you. The principle behind actual surfing is the same as both wakesurfing and the conveyor belt and flow rider videos. You are riding DOWN the face of the wave. The water is rushing upwards to form the wave and keeping you in a relative position in the wave.

Your example of the broomstick is a valid one, but a little misleading. The broomstick is like the wave, but the broomstick is not what is pushing the car. The surface of the table cloth (water) is being lifted up and making an incline for the car (rider) to ride (surf) down.

The whole thing of the cruise ship or wherever the flowrider is located is irrelevant. They have them on ships, they have them on land, they all do the same thing. Pump thousands of gallons of water up an incline so you can ride down that incline without ever reaching the bottom. The reference about the rider on the flowrider on the cruise ship is the same as the old physics question of the race car on top of the train.

Surfing is finding the balance between gravity and the force of the water lifting you up and out towards the back of the wave.

"The wave is very long, plenty of push, driving with the boat evenly eighted is awesome."

Desi: This was in your post from yesterday. So is it Push or Lift?

I think anyone who gets butt hurt over the usage of the term push needs to get over themselves

It is lift. As I have said earlier. It is a term most people recognize, even though it is not the scientifically correct term. Push works but is misleading because people assume you are being pushed forward by the wave and that's how you're surfing. You are being pushed upwards and back towards the top and back of the wave.

It's one of those words like irregardless, which actually means without, without, regard and is the opposite of what you mean with the double negative, but people still recognize it simply as without regard. I concur with what ragboy said about it being an accepted term even though it may not be the most accurate term.

Lift/Push - whatever. Go tell someone that you think your wave has a lot of LIFT and see what they say. Just don't be surprised when they look like this: :confused: . Push is acceptable to me because if you tell a n00b that their wave has lift, you have to go into some long and drawn out explanation as to what the heck you are talking about. If I walk up to anyone on the street and say "it's like the wave is pushing you toward the boat", they will get that. If I walk up and say "It's like the boat is creating a wave that it is lifting you up (but not really) and creating a ramp that you ride down towards the boat", I already lost them. :D

Argue on...

I think you're all missing a key piece of the "push" discussion.

When I think of push, I think of my ability to keep pace with the boat. Because that's what you're trying to do, keep up.

You're surf wave is a wave of water moving from the center of the boat out away from the center of the boat, like the broomstick handle. That energy DOES act on you and push you forward. We wakesurfers then point our boards in a different direction because we want to move (ideally) parallel with the wave, that way we have more time to ride in the area of the wave that has the most kinetic energy acting on us. In most cases, the spot where the wave curls over is where the most kinetic energy is releasing. By turning our boards on the wave and using the edge, we re-direct that energy acting on us and move parallel to the wave and in the same direction as the boat. Now you are moving in your desired direction and you are moving at some speed

Now, here is the interesting part, there is a sweet spot where the amount of energy produced by the wave of water is enough to allow us to keep our surf boards on plane and moving at a fast enough speed to keep up with our boat. As you speed the boat up, two things happen.

1. The boat moves faster. Plain and simple. If the boat is going 12mph, then your minimum speed needs to be 12 miles per hour. You now require MORE kinetic energy from the wave to travel at a minimum of 12mph.
2. Displacement of the boat changes and thus the amount of kinetic energy from the wave changes. The scientific changes here escape my knowledge level, but let's examine the scenarios.
-----2A. Kinetic energy is decreased, the boat speed is increased by 50% and kinetic energy is decreased by 5%. That means you're moving slower and the boat is moving faster. This translates to feeling like you're getting less "push".
-----2B. Kinetic energy is increased, this would HELP you keep pace with the boat, but to what extent? Is it enough to keep pace? If you increase your boat speed by 50% but your kinetic energy only increases by 5%, that's going to feel like less push.

I hope now you see that push is really more about kinetic energy of the wave as it relates to the speed of the boat.

There's also more to this than the wave being a ramp. I've surfed behind boats that have a very steep ramp but for whatever reason, you don't seem to move forward and fall out of the pocket no matter how hard you lean forward (without pearling the nose). So that begs the question, is it all LIFT or is there some PUSH? :D Just because there is a ramp and your physics says that if you are pointed downhill, you will go downhill doesn't work with a wakesurf wave. It feels to me like the wave is actually forcing/pushing you backwards in those circumstances.

This is a good discussion...

Why can't we use an accurate term?

Use whatever you want but there's clearly more than just lift/push at play here so that's where the confusion lies and technically, neither is correct. Until we figure out something different, I'm going with Push.

Good stuff. I think with speed, weight, and certain hulls, the wave will actually get around behind you more and push you more directly in the direction you want to go, which gives a greater sensation of push. Some wakes it seems like you are riding more parallel, and you feel like you fall out easier, and on some wakes you fall back and the wake can kinda grab you and push you forward. I know our 24Ve was more like the second after our modifications. Either way, there is energy, and its propelling you.

http://jasonrstover.files.wordpress....13/04/wake.jpg

Passage of a boat through the water inevitably sets up a forward moving wake ...... this nugget from the physics of boat wakes and propeller placements on large ships

The boat is always going forward and the wake is always going forward ...... seems to me this creates some sort of push somewhere and somehow ......

ragboy, you nailed it on the wave angle. Some waves definitely move in different directions which I think makes them easier to ride. wofrankwo is on the right track to.

The wave certrainly isn't moving in exactly the same direction as the boat, but it's definitely not moving perpendicular either. It's at some angle in between, depending on how your boat is setup.

Wofrankwo. This is very true. The reason you have a forward moving wake is because the boat displaced water in that direction and continues to displace water in that direction, so the water fills in towards the boat as the boat leaves the area it is displacing. How the weight is distributed in the boat, the shape of the hull, anything that may affect the wake, trim tabs, props, swim platforms, surf gates, etc. will determine the shape and direction of the wake.

Timmy that is exactly what people do when I mention lift.

I agree, the term PUSH is more accepted and better understood. However I do not agree that it is actually pushing you. My theory is that it is actually lift. Surfing is hydroplaning. When things hydroplane they lift (think hydroplaning car). You start moving at the same rate of speed as the wake and if you move slower than the speed of the wake you sink. The energy of the wake lifts or planes the board allowing you to drive down the line or quickly match its speed to fall back on it. Also think that when you start falling back there are a few tricks to get caught back up... Pumping and using the fins to create lift (wing) or doing the bounce on the front of the board which creates an opposite reaction to sinking which is lift. Hydrodynamics are at play with surfing and lift and drag are the two biggest components besides gravity. I believe the wave is lifting the board, gravity is pulling you down the face counteracting the drag. My theory only but it is how I understand what works. I understand what Robert is getting at and with good diagram. This really opens up to good conversation. I just feed that right now the sun is circling the earth and we have to prove otherwise.

So for now and likely for ever "Push" is just the easiest way to describe what is going so people spend less time thinking about it and more time riding.

Timmy, there is a point where it can be too steep and the speed of the water rushing back up is faster than you riding down. It's a happy medium. When I was surfing a G25, the driver would ask the riders how they wanted their wave adjusted while they were riding. He would ask if you wanted more vert or more ramp.
Everyone looked at him like he was crazy and had him explain what he was referring to. Vert, he said, was the height of the wave, or steepness, up and down, vertical. Ramp was how long it was in relation to the boat.
This made a lot of sense to everyone and we were able to tune the wake on the fly to what we wanted.
If you have too much of one and not the other you're gonna have a bad time.

person 1: wake surfing is "fun."
person 2: wake surfing is not "fun"

what is "fun."

does "fun" exist?

could you also say the wave/wake "lifts" you by "pushing" you vertically?
or
could you say the "push" of the wave is very "lifting"

i just want a boat...

http://www.rodndtube.com/surf/info/Hydrodynamics.shtml

Just did some googling. There is actually lots of good studies and papers on this subject as I just found out. I guess I do not have to make my brain hurt thinking about it any more while riding as it is well documented. This paper really explains the concept of Lift and drag on a surf board. Pretty good read.

Some of the articles/sites I used when researching:

http://en.wikipedia.org/wiki/Wake
http://www.math.ubc.ca/~cass/courses...n/Mainpage.htm
http://en.wikipedia.org/wiki/Wave-making_resistance

and here is some great information:

http://www.boatsafe.com/nauticalknowhow/waves.htm

This would be a perfect February thread

Perfect thread right now. Our weather has been so crappy for like three weeks. Summer has yet to arrive. Only have 20 hours on the boat so far this season where I normally would have about 80 by now.

Bummer, we are hoping we will have enough water to finish the season.

I wish I could send some of this rain your way. Could send the cold temps and wind if you like Robert.

I'll take the rain. ;-)

My lord. I wanted to stay out of this discussion and largely will. I do not want to bring a science hammer down on anything. However, there are many forces at play here. Yes, under this scenario or that scenario one force may be the dominate.

Push, is an acceptable term when discussing wave science. Longitudinal waves are also called 'push and pull' waves. How an individual interprets 'push' and 'pull' is multifaceted.

Circular orbital motion. up and backwards, up and forwards, down and forwards, and down and backwards completing the circular motion. Up can certainly be thought of as lift, but are you being lifted up, pulled up, pushed up. Pulled can probably be literally removed from that scenario under most peoples understanding of pull. Forward? are you being push forward, pulled forward or lifted forward.

A displacement wave behind a boat is not just a displacement wave or water backfilling. There is a lot more going on.

Please drop the science hammer. I would love to know exactly what is going on there. I think what you're saying is that we are all right and all wrong as we're all saying one part of the equation, correct?

retarded debate. I can't wait till you guys get to the living room/family room conundrum or the parkway/driveway debate. Oh and for bonus points, sweaters are called jumpers in the UK.

Right, wrong, tomato, tomato the world is a wonderfully diverse place.

I honestly don't care anymore. My only bone to pick is Robert. Just because Robert says it's ok, that doesn't make it so. Most everyone else has made perfectly reasonable explanations of why it should be push. That's fine. I'll buy it. We all know what's going on and if we need to stick a word on it well, a rose, by any other name, would smell as sweet.

When I say push in the ocean, I am usually referring to period swell. For example, "The waves were small, but they had a lot of push" = "The waves were 2ft, but the period swell was 11 seconds". Or for non-surfers the wave height of the swell was small, but the wave length was long.

I have no idea how that translates to wakesurfing, but every time I have been on a boat with someone b*tching about not having enough push it is because they don't feel like they should ever have to pump/carve to keep up with the wave.

Lot of pressure. You've gotta rise above it. You've got to harness in the good energy, block out the bad. Harness... energy... block... bad. Feel the flow, feel it. It's circular. Its like a carousel-- you pay the quarter, you get on the horse. It goes up and down and around. Circular... circle. With the music, the flow. All good things

You all make it way too complicated.

Lift is the force of the wave going upwards, filling that "hole" in the water that Desi and others have described. Gravity is the force of the earth pulling you down towards the center of the earth.

Push is the forward motion generated from those two opposing forces acting against each other. Saying a wave has good push is simply saying it has a lot of ability to provide forward energy.

https://lh6.googleusercontent.com/-e.../s800/Push.jpg

If we were only talking about LIFT, we'd be on a trampoline, going up and down. we're not. a wave is not horizontal and thus we go forward via PUSH.

Flowriders and artificial ski slopes aren're great examples as they are using two dimensions (lift and gravity) to describe something that is 3 (or more) dimensional. I just rode a Flowrider on Wednesday. There's only lift and gravity really. However, in the wave pool next to it, there's actual waves that can generate forward movement.

Thats a very good explanation.

Right, and behind a boat you have a combination of displacement/backfill and a standing style wave you experience on a flow rider type system.

newwhit- I see what you did there. Nice.