How straight should a tournament boat path be?

Horton · November 2020

How straight is straight enough? There is a faction of the sport that believes that drivers should attempt be perfectly straight. On the other hand as a skier that might suck. Maybe the drivers should feel free to move the boat 5cm per ball or 10cm per ball or even all the way out to 20cm per ball if that is what is best for the skier.

This all assumes that the driver can put the boat where they want. Using the tolerance for human error is a different subject.

jjackkrash · November 2020

The driver should strive to be dead straight

Trying to drive straight and at the same time trying to not hinder the skier is one thing; trying to affirmatively help the skier with boat-path tolerances is another.

Nando · November 2020

The driver should strive to be dead straight

@jjackkrash said it pretty much perfectly- the driver should strive to be perfectly straight; the goal is to give the skier the best possible pull without giving them an unfair advantage.

dave2ball · November 2020

The driver should strive to be dead straight

Keeping the pylon in the middle but staying in rhythm with the skier.

Bruce_Butterfield · November 2020

The driver should strive to be dead straight

The driver should try to be as straight as possible, but no straighter.

Seriously, if the driver is capable of "putting the boat where he wants", he is capable of keeping the boat straight, but you are talking about a very small percentage of tournament drivers. Most drivers need that little bit of tolerance when the heavier/short line skiers try to pull the boat sideways.

A_B · November 2020

The driver should strive to be dead straight

There is “no help” in driving????? In your best Tom Hanks League of Their Own rendition.

MISkier · November 2020

The driver should strive to be dead straight

For some reason, I think this may not be just a random poll. I sense a prelude to another topic, announcement, or controversy.

ral · November 2020

The driver should strive to be dead straight

Tolerance is to allow the driver to be less than perfect in keeping a straigth line, but not to help the skier.

A 9 cm consistent deviation in favor or against the skier would not stand the rule below:

If an Approved Boat Path Measurement System (see below) is being used, the deviation shall be calculated as being the average of the maximum two deviation measurements taken when the pylon of the boat is within a zone from 10 metres before to 10 metres after the buoy the skier is attempting to round. A minimum of ten deviation measurements must be taken within this zone.

If an Approved Boat Path Measurement System is being used the Net Cumulative Deviation (favourable deviations shall be offset by unfavourable deviations, the sum of which shall be the Net Cumulative Deviation) shall be also measured throughout the course. If the Net Cumulative Deviation through the course exceeds the allowable Cumulative Deviation Tolerances at any buoy as set forth below, then an optional reride shall be awarded if the Net Cumulative Deviation was a disadvantage to the skier unless the skier makes a complete pass, and a mandatory re-ride shall be required if the Net Cumulative Deviation was an advantage to the skier. If the skier does not complete the pass the Cumulative Deviation up to and including the buoy the skier was attempting to go around must be measured.

Cumulative Deviation Tolerances

Buoy Deviation max
1 20
2 28
3 35
4 40
5 45
6 49

The_MS · November 2020

Give the driver some room to move if he gets sacked by the skier and also give ZO some time to relax a bit if it gets whacked. It doesn’t have to grab it all back in that segment.

Than_Bogan · November 2020

The driver should strive to be dead straight

Have I entered a parallel universe where @Horton has embraced metric?

ral · November 2020

The driver should strive to be dead straight

Anything below 10 in he measures in cm...

Horton · November 2020

The driver should strive to be dead straight

Below are clips from the AWSA rule book.

10.07 Boat Path
A. The boat path is intended to be a straight line along the centerline of the
course.
B. Where end course is available, the towboat pylon shall not deviate by more
than 20cm (7.87in) from the course centerline. For instances where end
course video is not available, the boat shall follow a straight path as close to
the centerline of the course as possible.
C. Class E tournaments also see Rule 14.04.B on Record forms.

1.12 Tolerances
In any activity involving the performance of an official where a tolerance is involved, it is the official's responsibility to be as close as possible to the actual specification. All tolerances are to allow for human error and the use of tolerances by Officials to improve skier performance will not be tolerated.

ral · November 2020

The driver should strive to be dead straight

IWWF already considers the specific rule above when using a path controlling system. AWSA's 1.12 rule clearly states that "helping" is not tolerated.

Horton · November 2020

The driver should strive to be dead straight

Here is the rub.

No one can drive perfectly straight. The tolerance is a necessity. Personally, I am an average-ish driver. I often use up 10cm at every ball up and down the lake and I am really trying to go straight. Get me out of my preferred boat and it gets worse. I have NEVER claimed to be a great driver.

The very best drivers can keep it under 5cm up and down the lake most of the time.

Maybe the only negative comments I have heard about SurePath are from some very high end skiers. They think that with real time GPS data drivers will strive to be perfectly straight at the expense of a "feel and rhythm". This is where we get into an interesting grey area.

If a driver can keep it under 5cm per ball but goes out to 10cm per ball to just "dance" with the skier is that a bad thing? If that is ok then why not 15cm? When does dancing with the skier at only 5cm per ball become pattern driving?

Driving straight-ish AND and making it feel good for the skier are not necessarily mutually exclusive but require extra skill.

Don't forget that we need to also account for human error.

So many shades of grey. I hate shades of grey.

MISkier · November 2020

The driver should strive to be dead straight

I think the answer to this question:

When does dancing with the skier become pattern driving?

Is when it occurs:

when the pylon of the boat is within a zone from 10 metres before to 10 metres after the buoy the skier is attempting to round.

ral · November 2020

The driver should strive to be dead straight

What happens when he dances the other way around with another skier? And when the dance means a world record or a medal?

Pattern driving is defined by cummulative bias. Human error means you err in both sides and bias is cancelled.

Tomorrow we will have Sure Path for the first time in a tourney here. And the local joke is that the local Senior skiers will lower their score...

Horton · November 2020

The driver should strive to be dead straight

@MISkier oddly that is both too black and white and unclear.

jjackkrash · November 2020

The driver should strive to be dead straight

When sure-path grows into auto steering its best feature will likely be its lack of ability to listen to skiers lobbying on the dock and its lack of caring whether the skier hits a PB or record when it is driving. And I suspect scores will go down at first and top skiers will bitch about the "bad pull" that is straight down the middle.

ral · November 2020

The driver should strive to be dead straight

@horton, on @MISkier's comment, the full text is:

If an Approved Boat Path Measurement System (see below) is being used, the deviation shall be calculated as being the average of the maximum two deviation measurements taken when the pylon of the boat is within a zone from 10 metres before to 10 metres after the buoy the skier is attempting to round. A minimum of ten deviation measurements must be taken within this zone.

Horton · November 2020

The driver should strive to be dead straight

@ral That defines deviation but it does not differentiate between pattern driving ( cheating ) and driver error or an unmanageable boat.

The math is clear. How to interpret it much more complicated.

Horton · November 2020

The driver should strive to be dead straight

@ral I expect you are going to love SurePath. To me it really is a paradigm shift. I am curious how you will think differently after the weekend.

I disagree that pattern driving always shows in a positive cumulative. That is part of the problem. Pattern driving is very hard to define but if you know what you are looking for you know it when you see it.

Skoot1123 · November 2020

The driver should strive to be dead straight

First let us define what a tolerance is for:
An allowable amount of variation of a specified quantity. - Google Definition search result

Strictly speaking the boat path is “supposed” to be straight as an arrow. Statistically and practically speaking this is improbable if not impossible (@Than_Bogan - run the numbers?). Hence the reason a tolerance is provided.

I believe a separate subject is the “pull” feel between the skier and boat. The tolerance provides the latitude to do this. But I’m not sure the main intent of the tolerance was for the skier, I think it was for the driver. Has the allowable tolerance changed over the years?

Another aspect is how the tolerance is counted ie: is it cumulative or individual values for each buoy?

I would think most boat drivers would want to provide the same pull for each skier. (At least that would be my goal). If they aren’t trying to do that then I would think more questions and concerns of bias would be raised. As a driver if I heard a skier ask me to bias towards one side or the other on even or odd buoys I would tell them to fly a kite. The STANDARD is straight down the course.

Perhaps this is way off base. But also how I feel about it.

markn · November 2020

I have the opportunity to regularly ski behind the driver who pulled Open men at the Swiss Pro open. Just as a reference, they were using the SurePath. The driver pulled "all green" in the entire second round and the finals,every pass, and I did not hear one complaint about the driving.
I think a truly skilled driver can keep the boat "in the green" (with narrow tolerances) and still make it feel good for the skier. His driving is amazing....second only to my wife's.....but she "gives me a little boat".

Chad_Scott · November 2020

The tolerance is for the protection of the driver and not to be utilized to enhance the skiers performance. Honestly as the gps boat tracking devices become mandatory, the pattern driving will take care of itself. Outside 49 cm cumulative the pass will be considered bad and out of tolerance. I think all driving is pattern some good pattern driving and lots of bad pattern driving. It’s more about being in the right place at the right time to not hinder the skiers performance or path they are trying to take.

ral · November 2020

The driver should strive to be dead straight

@Horton, we can talk a lot about pattern recognition. I work in Advanced Process Control and AI/ML process optimization, so I can tell you that human beings are pretty good at believing they can detect patterns but really bad at it. Machines are far better.

For the rule, as per what I understand from reading it, if you have a pattern favoring the skier of slightly more than 8 cm in each buoy, you will be out of tolerance.

klindy · November 2020

@ral By definition with the slalom course being symmetrical with 3 buoys on each side, EVERY pass follows a pattern - literally. My point is, I suspect a human or machine will detect a pattern pretty easily. The hard part is with @Chad_Scott was saying about being
a "good pattern" or a "bad pattern". I would suggest that a truly random pattern takes a pretty bad driver to get right (or wrong depending on your perspective).

@Horton probably one of the most beneficial things you can do is to define what pattern driving actually is. Not having a definition is the cause of a lot of misunderstandings and controversy.

I'll take a stab at part of a definition. There is a difference between a driver "resisting the skier" and counter steering to keep the boat straight and a driver shifting the boat across the centerline of the course BEFORE the line is loaded by the skier. Clearly the effect on the skier is different and, likely, noticeable by the skier. A driver that is "resisting the skier" will use the tolerance if they under or over estimate how much counter steer is needed. Whereas a driver who is shifting the boat across the centerline goes just so far and blocks the boat from moving.

Watching end course videos for the first driver you tend to see the boat path slowly slide left or right as the balance between the skier load and counter steer vary. However a pull where the driver is shifting from left to right before the line loads tends to be a pretty tight zig-zag down the course with fairly long distances between the movements where the boat travels basically straight.

I'm not addressing or even suggesting that skiers prefer one way or another but I think what I outlined above are two distinctly different "patterns" of driving that are both in the current tolerances and observable.

Chad_Scott · November 2020

@klindy my point exactly. The definitions are sometimes difficult to actually define with regards to pattern driving. It is the reason I am a big proponent of the gps tracking system and hopefully the powers that be can decide on a clearer definition of the rules as to what is acceptable versus what many have defined as too subjective today I believe the tracking systems will put an end to drivers taking a risk and flirting with the tolerances. The system doesn’t lie and takes the subjectivity out of the equation for the decision makers. Until then .......

klindy · November 2020

@Chad_Scott I agree that a gps tracking system will sort a lot if this stuff out quickly.

At the risk of complicating things, I think that cumulative deviation is either the wrong way to look at it or there should be another dimension we watch too. The amount of movement between buoys would help I think.

Right now, the boat path can vary by 20cm from the centerline at each buoy. What if the total 'correction' between consecutive buoys could only be 20cm. For instance, if the boat was 15cm to the right at #1, it could only be a max of 5cm to the left at #2. In other words, the movement between buoys may matter more than being able to drive straight for buoys 1-3 then move 15+cm on either side of the centerline from 4-6 to "help" the skier get out the gate. Just a thought about a different way to look at it.

jayski · November 2020

The driver should strive to be dead straight

After spending since May with Sure Path and having it at a dozen tournaments and countless drivers using it at multiple sites there are some things that came to light in regards to this topic

First time users worry more about being down the middle at the expense of the skiers, this probably relates to the Pro's concerns. Some drivers got 'used' to Sure Path and relaxed it became better for everyone, some could not shake the 'down the middle at all costs'

Being towards a skier at each buoy DOES NOT necessarily equate to a good or helpful pull to a skier

Sometimes the skiers relayed the pass felt incredible and a driver "off sided" them once or more even

Sure Path data alone will not make for a better driver, looking at your path after a pass is not enough to analyze what occurred, additional knowledge of what the skier did during the pass helps analyze what occurred and why, where the driver may have erred and why

As drivers we should all strive to be as close to center line as possible, but not at the expense of the skiers. Drivers need to be more educated about their skiers, how/when they pull out, their tendencies through the course etc and tournament organizers need to stop having 3 different drivers for each of the skiers 3 rounds. Same driver, same skiers for all rounds, drivers can learn about the skiers, skiers gain comfort with how the driver drives, makes for better scores

Maybe slightly, maybe a lot off topic, I don't know...stay down the pipe but don't screw the skier

ral · November 2020

The driver should strive to be dead straight

@klindy, the intent of the rule is straigth path. As is the speed intent (constant speed).

When ZO came with its "gentle" first version, that looked at achieving the intent, everyone hated it. So it changed, but on an automated, consistent and repeatable way (which from a conceptual point I did not agree then, but I do agree on a practical way when behind the boat...). Not in a way where a human being can arbitrarily decide where to speed up/slow down. I guess the same thing needs to apply when auto-steering is deployed.

In the meantime, I do have an issue with drivers having in mind favoring the skier (or harming the skier), on a non-consistent and repeatable way. I believe drivers should have a straigth path in mind.

Horton · November 2020

The driver should strive to be dead straight

@ral

When ZO came with its "gentle" first version

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How straight should a tournament boat path be?

How straight should a tournament boat path be? 53 votes

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