After Zero Off - Whats Next?

[LeonL]

Ah, the puck problem! $450, or so I've heard. Available from Garmin at $79, but is the software inside the puck the same? If not who can load the appropriate software to keep from getting robbed by ZO? $375 profit to pass it on, or even to load different software seems like robbery to me.

[ForrestGump]

Why slalom doesn't need a rail.............

 

JUST BECAUSE. What a stupid idea. People are already complaining about not enough sites.

[6balls]

A rail...we would then need to have a rail in order to train on the current tourney system?? Will the rail have settings like Prostar 5.7 C2 + etc for those of us still running boats and need that same "feel" (and a judges seat)?

 

If/when it becomes a rail practice will have to count for me.

[oldjeep]

Rail seems like a great idea, if nothing else to put into existing wakeboard cable parks and get the kids interested in trying slalom out. The thing you would have to work out is what happens when you wipe in the middle of a run? (What do they currently do at the cable parks?)

[Chef23]

I ski on public water and there is no chance of a rail ever going in. If tournament skiing goes down that path I will probably stop skiing them. We would still need a boat because of tricks so you don't eliminate the need for a boat.

[oldjeep]

@rico you would definitely need a really big/heavy flywheel to maintain the speed. Doesn't really seem like much of a technical problem.

[Dirt]

They were testing/using a boat path deviation monitor in a MC two weeks ago. I am not sure how it works but I believe it was GPS based. Direct feedback to the judge and driver on each pass. Maybe someone knows more about it.

[Than_Bogan]

I don't think there's much that would actually drive me from the sport, but completely removing the boat would indeed finish me off.

 

I concur with most of the comments above and especially:

 

The last thing we need right now is more barriers to entry. We have to find ways to make it easier to get into the sport. Everything is accurate enough now for 99% of the competitive skiers. Indeed, we should be willing to trade some of that accuracy for greater participation if there were a way to do so.

 

And that's coming from a guy who would have a lot of fun making software for a laser tracking system!

[klindy]

@Dirt‌ Splash Eye has that system already. With the Splash Eye slalom system you get gate videos, end course videos and instant automatic review of both. With a target on the pylon the system will track and graph the boat path. At the end of the course a driver with a smart phone can get instant feedback. Pretty slick system.

 

It was used at the Nationals last year and the tracking system was tested extensively. Best I know it worked pretty well.

[Not_The_Pug]

@klindy the one @Dirt was talking about was mounted using an old PP judges display in the boat so the driver could get feedback immediately, it is just one someone is playing with in this area. I gives centerline deviation at each boat guide.

[RAWSki]

Why do we need so many combinations of speed control settings? no matter the engine, prop or skier size the goal is the same.... K.I.S.S, the boat needs to proceed through the course as straight and consistently close to desired speed as possible. Having so many variations seems like overkill and just causes confusion for everyone. "A or B or C" might be fine, but ABC & 123?? Darn 'geek engineers'

I will be interested to see what the next system brings....

[Deanoski]

a new speed control that gives the same pull to big skiers as it does small skiers

 

example the light skier 160lbs that uses the plus setting comes in hot and at 3-4 ball the boat slows down to get the time correct. verse the big skier 195-210 that comes in at speed and then at 3-4 ball races to keep the time right. the GPS uses only 1 satellite and just does not react fast enough

 

I hope to see a new system soon.

[Than_Bogan]

As a certified Geek Engineer, I can tell you a bit about software parameters. Nearly all of them fall into one of two categories:

 

1) Actual measurable stuff. For example, the weight of the skier.

2) Voodoo parameters that have to be exposed to the user because the algorithm isn't good enough (yet).

 

I have and will continue to make software that has voodoo parameters. We can't sit around waiting for everything to be perfect, and if the user can find any way to set them, the software may have value. But it's always the goal in "some future release" to eliminate the need for voodoo parameters.

 

It is not the goal of Geek Engineers, or at least the good ones, to provide parameters for the sake of having more parameters. Indeed, I hate ABC/123/+ at least as much as anybody. But I understand why they are needed -- for now. I basically can't ski at "3" at all, but some bigger or stronger skiers pretty much can't ski at 1. Someday when the system "just works" the parameters that do not directly relate to real-world measurable things will go away. That day may or may not be soon...

[RAWSki]

This is one of the problems with our sport we have accepted the 'voodoo' as progress. I can't think of other sports with these kind of variables? RPM based Accuski & PP only required weight of skier/crew and minor RPM adjustments to provide a very nice pull, then PP came with a switch and KY+/- and ZOx9. It's a shame really.

 

However, Splash Eye sounds like a very cool system and something that provides almost instant feedback and confirmation of a good run.

 

Hoping the good stuff survives and helps us!

[skosney]

Laser sighting might be good as an aid to the driver, but I don't thing a path guidance system is even close to being required, especially with the new boats. There have been and continue to be a lot of great drivers out there that can drive a straight line so if they know they are on center they can keep it there. Even with the new boats (and certainly with the old boats) if you react to what happing you won't drive straight, but if you are pro-active and almost anticipate what to do, the boat path will be nearly perfect and certainly better than any mechanical/automated system. Rails systems will kill an already dying sport, I don't know about you, but the skier to boat communication/interaction in both practice and tournaments is a big part of the sport for me, which last time I checked, is suppose to be fun.

 

I do think there are some positive merits to speed control and a focus on improving those systems is where the effort should be made. There are too many good skiers that are being penalized because their style or size adversely effects the boat pull quality. Again, systems that react will never match a good manual driver. I use to drive each skier at near perfect actual times (even with all buoy timing) and many skiers assumed I was driving on the slow end of the tolerance. That being said, I do like the concept of speed control and my arsenal of drivers has expanded dramatically. However, when the best pull you can receive is achieved by not actually engaging the system, there is a problem.

 

Perhaps the speed control systems could be programed to allow a bit more deviation from buoy to buoy, that way if I skier digs in deep on one term they won't be blasted into the next buoy just so the time can be perfect for the next timing segment. How about a rope load sensor, like Jump, to help the system determine when and how much throttle is required. Between that and knowing the boat position in the course, a more program could be developed that could be fair to all skiers. Perhaps this has been attempted without success, I know Perfect Pass used a load sensor for slalom.

[Deanoski]

well said Sean

[Craig]

First, ZO is fantastic and has helped my skiing enormously, I cannot imagine going back. I also tend to follow the 'shut up and ski' philosophy but I am a geek as well and enjoy thinking about some of this.

 

The voodoo parameters @Than_Bogan‌ speaks of are a result of all the complaining about the original ZO versions. They represent what we cannot quantify about how to couple the 'feel' of the pull to a consistent speed.

 

If I recall correctly, the original (perhaps just he prototype versions) of ZO had no parameters at all, just set a speed and go. As an engineer this was beautiful, and just what some of you are saying you would like. Of course, everyone hated it, so much so that the ABC was introduced, then ABC/123, now ABC/123+/-.

 

To eliminate ABC/123+/-, or generally simplify the software, would require a way to predict how the pull would 'feel' for every individual, in advance without an input to the software.

 

ZO has to do this on some level for the engine (the software has to predict what an engine will do when it gives it a signal to go faster), I presume they use an empirical study to characterize an engine or series of engines and have hard programmed that information into the software. So how do you do that for each individual skier with respect to feel?

 

I don't know, but it is interesting to think about. Personally, I think asking the user for a preference is a fine compromise. However, I may be biased as I don't think ZO is an issue anyway.

[Than_Bogan]

One thing to remember is that neither PP nor hand-drivers ever asked skiers for feel parameters. So there is an existence proof that the information exists to just do the right thing. I'm not saying I know exactly what that information is, but there are lots of things one could measure that could be useful: for example the rate of deceleration off the ball will immediately tell you if this skier is a "hard puller" (whether by weight or style). And after two probably-warm-up passes, you've got a nice collection of data about 12 buoys specific to that skier.

 

And it doesn't all have to be reactive (and maybe it already isn't). A relatively cheap computer can do a million instructions in one millisecond, so if you make a guess about what to do next and then your data shows it was wrong, you've still got plenty of time to do something else.

 

This sounds like a hard problem to me, and maybe a very hard problem. But not impossible.

 

But as @Gator1 pointed out, there's really not that much money to be made, and as many have pointed out, ZO works well enough for most. So any future improvement mostly has to be someone who desperately wants to prove it can be done.

[gator1]

"WE" won't do what we should have done years ago. And that is because our egos can't take it.

 

What we should do is run the boat 36 or 34 mph constant speed. The boats are strong enough, and the DBW cruise is fast enough to do it.

 

ALL of the voodoo shit in ZO is there to wean us from hand drives that let the boat vary up and down by up to 1.5 mph. In effect, we program the computer to "let the boat speed vary some where the skier needs it to vary, and let it vary different amounts depending on the skiers preference, while in average running a tight time". That requires a lot more voodoo than "run 36 to the hp limits of the boat"

 

If we ran the boat constant speed, everybody's average would drop about 2 passes. Including the pros. And we'd have to asterisk all the records.

 

And guess what: Boat path would matter a LOT less.

[Than_Bogan]

@gator1‌ I agree with about 90% of that. But do you think it's a misplaced fear on my part to think that nearly perfect speed would result in even more wear-and-tear injuries? Mentally I equate a nearly-perfect speed as being similar to a truly zero-stretch rope. Am I off in that comparison?

 

Or would I be saved from myself because suddenly I'd rarely be able to run -32 and so I wouldn't get into the hits of -38? (Btw, I've made the case that 34 is more dangerous for many people than 36, for exactly that reason: let's you get to shorter line lengths which come with more Bad Stuff.)

[6balls]

I don't dislike ZO or my setting on it. Some of my best skiing is on ZO despite limited chances. Having said that...why did it have to get more complex and tailored to the individual beyond individual preferences in equipment? What was wrong with stargazer on a drive by wire boat? I thought it was fantastic and it was simple.

 

At this point certainly there is no going backwards...so I vote leave ZO the hell alone. Runs great times, lots of user preferences, and someday soon more skiers will be able to afford depreciated boats with ZO like the one just sold by @webbdawg at a very reasonable price a few days ago. Change it significantly again and the cycle repeats leaving lots of skiers "out" for financial reasons in terms of having tournament speed control on their practice site. Firms selling new boats likely disagree as there does need to be a reason to buy them other than wake at this point.

 

 

[Ghibli]

@Than_Bogan Maybe fewer injuries because taking hits and scrapping would become futile? Most have given up trying to muscle the boat around, or at least trying to give up the urge, already. That handle gets ripped away pretty well as it is now. And in most cases, consider yourself lucky you couldn't hold on longer.

[Craig]

@Than_Bogan‌ , a very hard problem with no market, exactly the point I was alluding to. I agree, it is not impossible.

 

@gator1, yes, fixed speed. What the first versions of ZO were attempting to do, and almost certainly did better than the current versions.

[gator1]

I can't draw any data based conclusion on wear and tear of constant speed vs. ego stroking speed control.

 

I THINK constant speed is safer, since less extreme angles means lots of good stuff. Not the least of which should be less people sticking stuff through the handles.

 

It didn't feel like a no stretch rope when I skied it. If you're curious, have somebody hand drive you and gas it to maintain speed as close as they can.

[BraceMaker]

I don't mean to harsh anyone's vibe with the rail comment, I like playing around on boats and water in general. I don't mean to imply a rail would replace the tournament scene.

 

But I think you put something withing 45 minutes of a place like chicago and you'd get some skier development. Eliminate the need to have a good driver sit in the boat for hours at a time and you could have skiing all day long and lights on the trolley for night skiing.

 

 

Its a different subject entirely.

[klindy]

Question (because I haven't tried it myself). ZO is a GPS based system which triggers on the entrance gates to "start" the course. From then on it maitains speed relative to the various settings to obtain an arrurate time thru the course. I've seen virtually everyone idle through the gates and hit the button when the pucks are inline with the entrance gates. Same at the exit.

 

To me that seems to be subject to a pretty wide tolerance (feet?) yet times consistently come in within .01 seconds regardless of the skier, ability or techique or even whether they fall part way thru the course. That, conversly seems like a pretty tight result.

 

So my question, has anyone purposely set the exit gates to be (for example) at 6 ball instead of the exit gates? What happens with the times? Is the speed +.5mph (or whatever) faster as a result? Is there an error message displayed because the course was mapped significantly shorter than it expected?

 

The point is that with magnets at each buoy or even hand timing (human error included) you literally timed the speed of the boat THRU THE COURSE - specifically THAT course. Is the same thing happening with GPS based systems? Or are we timing over 259 meters regardless of where the buoys are located?

[Andre]

I think it's virtual timing thing.

ZO calculate the distance between each boat guide with the GPS and beep-time that segment.

ICBW...again! :)

[MISkier]

Some comments:

 

@klindy, if you try to map the course significantly shorter than normal or significantly longer than normal, ZO won't accept it. It will say your course is out of tolerance. You are timing over 259 meters regardless of whether there are actually physical buoys and boat guides at the expected virtual locations.

 

@rico, the course mapping is for the timer and also, especially for the + setting, for the extra speed coming into the gate and expecting to be pulled down for ball 1. If you never enter the course, I think ZO would continue to pull you at the speed that it uses before the gate, which would be something higher than the actual selected speed. It will respond to your skiing, but will return you to that "before the gate" speed until triggered by the virtual gate location.

 

@Craig, the ability to predict the speed results of engine response is based on some torque response algorithm. I seem to recall this from reading the ZO patent some years ago. I don't remember if it uses the CAN (closed area network) communications with the ECM to obtain power curve information or if it just "learns" the boat. I do recall that there is some amount of "learning" that occurs real-time and very quickly during the pass. But, I seem to remember certain ECM parameters as available to the torque response algorithm to get it close before the "learning".

 

@skosney‌, there is an accelerometer in ZO that senses the load on the boat as that load affects the boat speed. That is what they use in place of the old PP slalom switch now. The ZO responds to the accelerometer readings as if it were responding to load on a rope switch.

[ALPJr]

The rail idea is interesting. I agree with Bracemaker. I think it could help grow the sport, make it more accessible to the masses. For coaching, judging and fun factors you could simply design the tug with seats and a floor above the water in front of the pylon. Think bowling alley, several rails side by side traveling in the same direction. Multiple skiers, coaches observers along for the rides. Disney, Six Flags, etc. Use for tourneys too. The keys may be cost to build, maintenance and corrosion. Would possibly be good for boat sales as more people get interested in the sport. Would be a major change for the current tourney scene and change is often hard for some to get through.

[klindy]

Ok thanks for the clarification. That's how I understood ZO to work.

 

That said, the boat is traveling at a "constant speed" and produces times within .01 of a second all the time - regardless of the length of the course or the position of the buoys. Which means a course that's out of tolerance has no correlation to the time. So for class C tounraments (course not sirveyed) it's a crap shoot whether the consistent. I realize the speed is consistent but 16.95 over 250 meters surely feels a lot different than 16.95 over 270 meters.

 

As a TC I survey courses where centimeters matter - length, width, diagonals, averages, etc etc. All in tolerance or you need to adjust. Yet a speed control system which appears accurate to 0.01 second is calibrated by a push of a button on a roll thru the gates where the buoys are basically put of the line of sight of the driver. The boat can be going 33mph or 35mph but as long as the time comes out to 16.95 (or 94 or 96) then the times good. Completely irrespective of the course itself.

 

Don't get me wrong, I realize that I'm exaggerating and that reality is much closer but with all the variable skier profiles and other setting options getting the exact same times across a spectrum of skiers in precisely the same location in the lake seems improbable.

 

Just being the devils advocate here....I'm not bashing the technology or how it's used. Just trying to stimulate some thought.

[ForrestGump]

@klindy ZO only knows the position of the entrance gate. Although you map the entrance and exit, what you're really mapping is two entrance gates. From that point, it's going to calculate 259 meters irrespective of the actual length because it's only reacting to the input against it after it goes through the gate.

 

@rico ZO uses the entrance gate for it's gate "up speed". On normal it knows to accelerate to .4-.5 mph over the set speed at 34 and 36mph and then let's the speed fall off to actual after the gate position is achieved. On + it comes into the gate .7-.8 hotter at 34 and 36.

[ForrestGump]

The course has to be about 16 ft long before it'll error on you when you push the button for the 2nd set of entrance gates. I've mistakenly hit the button 10 ft short and it didn't error out.

[RAWSki]

Has there already been a thread or a 'Horton survey' asking for the most popular and least popular ZO settings? I saw something in WSM last year and it seemed like A2 and B2 were the favs

[skosney]

Personally I'm a "shut up and ski" kind of person too. However, the system does not work for all skiers. I'll admit I am old school and took an 11 year break from the slalom course so I may not be in the best position to critique ZO. After 3 years I'm figuring it out and starting to reach the same buoy count prior to my 1st retirement.

 

I understand that ZO senses the load but it's is how it deals with that load that needs improvement. The programing options certainly helps, but it is limited and will punish a skier to achieve a near perfect time. Adding more mechanical load sensor like the one used for Jump may provide a more rhythmic throttle control and possibly eliminate the need for ABC123. Simply stated, added throttle would engage when load increases (i.e. skier pulls) and the required intensity could be regulated by the "accelerometer" readings as described by @MISkier , and then when the load comes off the rope (i.e. skier stops pulling) so would the added throttle. Perhaps the times wouldn't always be perfect but each skier would have a fair ride.

 

It has been mentioned a couple of times that the settings are there to "wean" us old timers off of our "ego stroking" hand drivers that let the speed vary by 1.5 mph to move toward a true constant speed.

 

First of all, I think it the pull could be a true constant speed, meaning NO variation regardless of the amount of pull from the skier, this old dog would be ok with that. But even todays boats with all their size and horsepower can be slowed down which means they needs to accelerate to "catch up" and achieve an overall perfect time.

 

Second of all, in regards to hand driving, a driver that varied the speed by 1.5 during a pass wouldn't last very long pulling me, as that would be a terrible ride. Maybe I was spoiled by a pool of skilled drivers, but I would contented that the boat speed varied very little throughout the pass. The only exception would be when a skier overloaded a particular buoy which may result in that segment time being off, but most likely still in tolerance.

 

I have no ZO data to support this, but it would be interesting to see the speed variances +/- throughout a pass using speed control. I suspect they are similar to a good hand driver, the only difference being the timing of the required added throttle within the course.

 

I'll end my rant with a simple statement that I believe speed control is good for the sport and I fully support it's use. I just hope for continued improvements that move toward making the pull similar and fair for skiers of all sizes and styles. This is a great discussion topic and hopefully the passion we all share for this sport can inspire constant improvements.

[gator1]

@skosney‌ At the Madison WI tour stop I had my solid state speedo on the boat, which was part of the feedback loop for my cruise control. After they made me turn off my cruise, I still had a o-scope hooked up to my speedo. With Jack Walker driving, and BLP skiing, the boat speed dropped about 1.5 mph when Bob got in trouble and had to catch up. I could watch Jack catch that back up through the rest of the past. If he had enough segment or pass left to do it.

 

It rhythmically varied about +/- 0.8 mph when everything was going smooth, regardless of the skier. My cruise got that down to about +/- 0.2. And when somebody surprised it, would drop about .75.

 

Regardless of the numbers, a good constant speed pull at the limit of boat HP will take close to a couple of passes off everybody's average. Didn't mean to harsh anybody's mello with the words "ego stroking".

 

And the limit of boat's HP and throttle response, coupled with a load sensor and high update rate processor, is so good these days that, if we did decide to go constant speed, it would be pretty damn close to constant speed. For everybody.

 

 

[ForrestGump]

ZO was given the mandate by AWSA to control speed to within .02. So they did it.

[boarditup]

DARPA is nearly complete with a small, inexpensive internal, inertial (think gyroscope) chip that does not reply on GPS for extremely precise navigation - think fractions of a meter. This frees the world up from the delicate, and likely unreliable GPS system over the long haul. Their goal is a chip small and durable enough to be shot out of a mortar for in-flight targeting - making something pretty dumb into a smart bomb. If this works out, particularly in the next 5-10 years, you will find GPS gone. However, this chip will be integrated into phones, vehicles, cameras, etc. This could be integrated into a puck placed on a ski for recording position in real time - or boat path in real time.

[klindy]

@ShaneH‌ .02 what? +/- 0.02 mph variance? +/- 0.02 kph? +/- 0.02 seconds per segment? Full course?

 

The words "control speed" infers mph or kph but it's unclear.

[skosney]

@gator1 Interesting information. To add some perspective, what year was that and what speed control system? Certainly the LaPoint's are great examples of big power skiers.

 

Are you contending that the current boats are capable of maintaining a true constant speed (meaning virtually no +/- variations in speed throughout the entire course)? If so, I contend that scores would suffer very little, because in order to achieve this, the boat pull would need to be in near perfect rhythm with the skier (much like ZO is now with a very light skier).

 

I've taken some passed behind a Correct Craft setup with more torque for jumping and I found the pull much smoother (less variation). It would be interesting to try an even stronger pulling boat. Perhaps it is possible, but the fuel economy really suck :-)

[Ghibli]

I say constant speed and ban the wing. Wonder how many buoys that would clip....

[gator1]

@skosney Yessir, that is what I am contending. We can always debate "virtually" but we're both on the same page.

 

However, we're not on the same page, or even in the same book of music, as concerns what happens if the boat does run close to perfect speed. I contend that on average you'll lose almost two passes. And I watched it happen to BLP and co. And that's why they made me turn it off. And it was a nice smooth power control. And it took two passes away from me and others.

 

But, maybe ZO has partially weaned us. So, I'd bet quite a bit on at least one pass worse.

 

The speed control system I used up in Madison was mine, which I built from around 81 thru 85. It was (is, still in the bud box somewhere in the basement) a true PID controller, based on vacuum actuation from an automotive system with extra accumulator, over sized vacuum plumbing and doubled up servo valves, and overclocked to 20x of the auto systems of the day. Feedback on speed came from dual pitot tubes driving Honeywell solid state pressure sensors averaged before reporting to the processor. The pitot tubes were 90 degrees to flow, and used stagnation pressure against a backstop to avoid clogging, plus no water flow into the opening due to pressure sensor right down there on the pitot.

 

Not that I remember the details or anything.

[swc5150]

I'm digging @gator1‌'s take. I've pondered how equal two skier's passes are. If an average of 36mph takes one through the course around 17 seconds, it doesn't seem two skiers necessarily take the same route to get there? A light skier in tune with the boat may keep an even speed throughout the course, for example. A heavy-hitter may slow the boat down much more when loading up, resulting in the boat having to speed up considerably to meet the 17 second pass. Obviously this is course 101 stuff, but to me it kind of seems like 2 skiers ran the pass under different conditions. I would think a constant speed rather than an average speed would make all things equal? Or maybe ZO isn't as far off as I think for the big guys? My bro and are just in the 150-160lb range, so we don't have a problem overloading the 200.

[DanE]

Is it even possible for a speed control to achieve true constant speed?

In that case it would have to anticipate the skiers pull, how? Gut feeling?

As soon as a speed control reacts to a deviation (i.e; controlling speed) the battle is lost, variation of speed has already ocurred.

What we as skiers feel as a good or a bad pull is the manner of how the speed control catches up to the speed swing.

[skosney]

Well that sounds pretty hi-tech for the 80's ... You should dig it out and run it on a newer boat.

 

[ToddL]

@RAWski This is an older survey... http://www.waterskiaustin.com/Competition/Resources/zo_survey.htm

Be sure to skim down the the bottom of the page for lots of preferences by skier style, size, etc.

[gator1]

@DanE‌ Virtual true is possible. Computers do things so fast it is virtually true.

 

Plus, we do get anticipation, since as the pull comes on the first 1/10 sec or so is load on the rope, rudder, and fins, but very little load on the engine. 1/10 of a second is an eternity to a modern control system. With a load cell in the rope you can anticipate the impending engine load before the skier gets into the work zone.

 

@skosney‌ Ya, it was a pretty badass piece of tech in those days. No reason to dig it out though, ZO could run virtual true if we told them to.

[ozski]

Ok here is a question, if we opted for a flat line pull how would that or should that apply to jump? Seems to me the way boats gas when they jump there could be tons of variation and advantage from one boat to the next. Is jump flying under the radar in this conversation? We know what the goal is for jump, bigger and then bigger again. More power, more gas...

[GregHind]

@gator1 I've loved reading your stories. Hook up your pickup and scope and show us some zero off traces please!

 

@ozski the way I see it jump speed control cheats like crazy. Have you seen how zero off "deploys parachutes" to stop the boat in time to make good segment times. Boat speed certainly is not constant... Current boats have a LOT of drag so they reduce speed quickly. They tend to dive the nose down when you drop power which helps wash speed. It would be interesting to see the trace but constant speed is not their goal. They want maximum speed at critical times whilst still meeting segment time requirements.

 

Not saying it should be changed just saying it isn't constant speed

[ozski]

Would more segment times in jumping solve the so called cheating issue? When you think about it jump probably has a bigger issue than slalom.

[GregHind]

@ozski too late to change it now. No way current distances and records could be matched if speed became more constant. Even in hand driving days jump drivers worked the segment times. The best could have the stopwatch back them up even though the jumper got slingshot into the next universe. Not cheating at all really. Just making the most of the rules.