Slalom speed versus timing

[boarditup]

So distance=speed X time.  From the beginning, we had AirGuides with tubes measuring speed.  Not real accurate.  So, math being better, we used the equasion.  Now, we have very accurate ways to measure speed several times a second.  So, my discussion question is this.  Should the rules be written to ignore time since we can precisely control the other two.  Meaning, the course is known distance.  The new SG and ZO can control speed within a very narrow range.  Should we embrace the new tech and throw out the stopwatch?

This question is the result of reading about the complaints about the "feel" of PP 6.5, PP SG, versus ZO.  At my level of skiing - 15-off - I cannot feel the difference, so I do not have a dog in the fight.  However, what should the goal be - "good times" that shows the average over the course and ignores the slight fluctuations (and allows for a softer feel) or constant speed regardless of the skier's actions (that may result in a harder feel)?  My read of the original rules was that the constant speed was the original goal.  The use of times simply allowed for a more precise measurement due to the math.

 Do we want to go there?

[Horton]

Karl,

You may have a point but we are in a ZO world. There are not options within USA WaterSki. The tech we have is the tech we have. What ever the feel is it needs to be the same for everyone - new boats or old boats.

[boarditup]

No arguement from me.

 My question is that since the old PP units, the new SG units, and the new ZO units are all software driven, what should the goal of the software be?  With PP, it was to replicate the best hand drivers possible. With ZO, it seems to be more of a constant speed.  Both are close to eachother in terms of performance.  Should we, meaning the AWSA, direct a goal of times or speed with the new technology.  Even the old pre-SG units can be changed with a new chip with settings that will do whatever the engineer wants.

 From a policy position, what should the intent of the rules be?  If there were clear direction and leadership, this situation could be cleared up next model year.  Without leadership and direction, there will be chaos and discontent until the market settles out and only one remains.

[Horton]

Intent of the rules? Wow you should look at what has happened to the jump speeds in the last 20 years  . . . . Now that is way out of wack with the way it was written...

[boarditup]

OK - I'll bite.  Please give me background on the jump rules.  I know nothing.

[ScarletArrow]

Same...I know nothing. 

I also don't get some of the complaints about ZO...and the concern for a soft feel in the pull.

I'm the same level as Karl (15off) and have only been skiing the course a short time, so perhaps I'm niave or just too much of a noobie...but whenI started skiing the course the thought NEVER occurred to me that he pull from the boat would going to help me by being "soft".

I thought the whole point of speed control was to get as exact times as possible through each segment - period.

The only question about differences in pull related to WHEN (e.g. - early, middle, late) you wanted the boat to apply more throttle to compensate for the skier pull.

Am I oversimplifying the matter?

I just don't see how a speed control device that slows down when you want it to and speeds up when you want it to (i.e. provides a soft pull) to the advantage of the skier.  How is this objective and neutral in a sport so focused on precision?

[Horton]

I was away too long to explain the pregression but when I was jumping a 5.5ft ramp was 5.5ft and speed was as constant is possible. The speed was not overy constant but we tried. As I understand it now,  a 5.5 is closer to 5.75 or more and the boats go as fast as they can under the rule. There is not attempt to tip actual speed or time. (OK maybe I am just bitter about how easy it is to go far now : -)

[Bruce_Butterfield]

Sorry Karl, you hit a nerve. The goal of Accuski was to replicate the best hand drivers [which they did hands down]. The goal of PP was to keep the speed as constant as possible [which they f'd up royally]. They tried to do that by considering hull type, engine sizes prop pitch, etc, etc. It took PP several years to get remotely close to the pull of Accuski. Now ZO is at the same point as PP was in 1998 trying to get a "decent" pull out of their system.

"Constant speed" was written many years ago with virtually no thought as to what "constant" really means - a 1mph swing was pretty good back then.

<<< End soapbox>>>

From a policy positon, the ideal would be a bunch of speed control options - the "best" system would win out much the same as the "best" towboat wins out.

To answer your question, speeds and times are the same - they are both averages over some distance (nominally the length of the course, or buoy to buoy). It's really the wrong question to answer.

Jump is a whole different ball of wax.

[JCH]

IMHO to go away from magnetic timing is a step in the wrong direction. ZO "timing" is calculated from way points and the perceived speed. IF something is out of calibration in the ZO system and there is no crosscheck, how do you verify someone's performance. (Think of the Malibu Open recently where the buoys moved) Someone will always be out there trying to get an edge, and as long as the only check is by computer and software, there is always a chance for a hacker to cheat the system.

 

[boarditup]

So the follow-on question is:  What is accurate and within specification or tolerance.  We now have only times, not speeds.  As long as the times are "good" we consider the pass valid.  However, there can be a lot of speed variation associated with "good" times.  The "best hand drivers" use a lot of English on the throttle to get the right "feel" with good times.

[DW]

If you can track and approve a run by using video for boat path, it is very simple today to define acceptable speed parameters and then validate those for any given run.  This type of thing is done routinely in many motorsports venues.  Software and calibrations are validated all the time.  Simple fact is the speed tolerance is not properly specified.

[Bruce_Butterfield]

<<So the follow-on question is: What is accurate and within specification or tolerance.>>

Very good question - I'll offer some things to think about. There currently is no tolerance on the swing in speed - the tolerance is on the average speed over a segment or full course. If you want to make a specification that the speed has to be 34.2, within (to make up a number) +/- 0.2mph, consider the following:

1) Now how do you measure the swing? GPS could theoretically do it, but you might need something like a radar gun on every pass to check the tolerance. Now we're making tournaments more costly and more complicated. Wrong direction.

2) What do you do if the tolerance is exceeded by a really strong skier? Re-ride? The skier will very likely pull the boat out of tolerance again. Mandate a "stronger" speed control setting? Is that fair to the skier?

3) Many speed control proponents use the argument that "everyone gets the same pull". This is an absolutely bogus argument. The only way that everyone can get the same pull is to use the exact same throttle setting and not touch it. If you give one skier a different amount of throttle than another skier, he is NOT getting the same pull. Trying to put a limit on the speed swing will make this situation worse.

IMO, putting a tolerance on the speed swing is not a good idea. The average speed over each segment is adequate and is really giving each skier as near the same conditions as practical.

I believe the real issue highlighted by the recent speed control swirl is that the "goodness" of the pull is determined much more by WHEN the speed control responds than by HOW MUCH it responds. The rate at which a shortline slalom skier loads and unloads the boat is simply much faster than even a GPS controlled DBW system can respond to and stay in perfect sync with the skier - there will always be delay in the response. In attempting to keep the speed "constant", the software will either hit the skier hard early, or stay on too long, both of which make the pull feel like crap. This mismatch in response will have a much bigger effect on a skier's performance than any swing in the actual speed will.

[eleeski]

Efforts should be made to match historic speed swings.

Speed swings can never be eliminated. Modern boats can lower the speed swings but at $4/gallon I don't want more power in my boat. Jump allows a significant overspeed - but too much and you are Beebe'd out as a cheater. ZO doesn't seem to allow enough speed swing for tricks (1/2 mph tolerance) to keep some happy. And the slalom furor over minor changes in speed response mean the speed swing has an incredible effect on the feel and performance.

Perfect times do not mean perfect speed. The GPS systems seem to miss a segment often. Instead of accepting that error in time and running the rest of the segments right on, the GPS systems seem to make up the timing error by overcorrecting. That is an intentional variation of the speed which is not allowed by the rules.

While I agree that the feel of the pull is critical, I disagree with Bruce that speed differences are insignificant. Since each .01 is about 6" in the course and slalom is a game of inches, those hot times or make up hot speeds cost us buoys! An honest driver last year would average 16.98. ZO averages 16.94. No wonder our scores are down.

Eric 

[HO 410]

Just an observation.

Can it be as simple as just two aspects of the approach to speed control that have changed that are changing the way these systems pull? (I am not sure if this goes for Zero Off as well as Stargazer, all my experience is with Stargazer)

1. Chasing times. Instead of just running the program it was told to run and then telling you how long it took to get from gate to gate, it will now adjust the program on the fly and speed up or slow down depending on how quickly or slowly it has gotten to certain points in the course. With previous versions of Perfect Pass, if the times were fast or slow, the onus was on the driver to adjust the program by adding or subtracting RPMs.

2. Oversimplifing driver input. The skier weight is the most important that comes to mind. At times it seems like one more weight designation, either a light minus (L-), normal plus (N+), or heavy (H) would clean things up. We have an 06 MC with Stargazer and it is giving actuals at one ball and mid-course more often than not. But when the skier is very light (either by weight or by style) the one ball time is consistently fast.

Oh well, I probably won't be skiing at regionals and will certainly not be skiing at nationals. I'm happy with the kinds of pulls I've gotten so far this year, except for the time I was pulled by an 04 Moomba with an old version of perfect pass.

It's debatable whether StarGazer or Zero Off were ready when the season began and even still now, but the biggest mistake was making a decision to choose one system as the speed control of the future without providing a three to four year phase in period.

[roda]

Isn't it the manufacture that put USAwaterski in this position, not the other way around.  I understood the patent settlement to have made this call for all future boats and aren't most tournaments pulled by the latest model due to sponsorship rights?

That seems to me like the market and patent law is driving the rules.

-Rod

 

 

[boarditup]

Rod - I agree.

Here is what it seems like to me:

 The software programs try to emulate some of the best hand-drivers - at least in technique.

The feel of the pull cannot be quantified and therefore cannot be completely equalized between skiers.

 Different skier prefer different pull characteristics.

The skiers at the low end of the performace spectrum usually cannot tell the difference between software programs. 

The skiers at the high end of the performance spectrum usually can tell the difference between software programs.

Somebody will always be unhappy.