Boat Path Measuring Systems overview

[Horton]

The new rules pertaining to systems like Sure-Path and SkiPath look complicated and confusing at first glance but are actually quite simple.

In my opinion, some of the terminology used is potentially confusing. There are two clearly defined regions where the boat path is measured for each ball. One of these regions is called “Zone” and the other is called “Buoy”. The boat path data from the “Zone” is known as “Zone Deviation” and the data from “Buoy” is known as “Buoy Deviation”. 

“Zone” starts 5 meters before the boat guide and extends 10 meters past the boat guide. “Buoy” starts at the boat guide and extends 5 meters past the boat guide.

“Buoy Deviation” is the number that most accurately defines where the boat is when the skier passes the ball and is the number most commonly used by drivers for reference. This is also the number used for the “Cumulative Deviation”.

“Cumulative Deviation” is simply the sum of all “Buoy Deviations”

Lastly, there is “Gate Deviation” which is 2 meters before and after the entry gate.

What you really need to know.
For “Zone Deviation” and “Buoy Deviation” if the boat is AWAY from the skier by more than 20cm an optional reride will be awarded. The skier can improve. The score is protected.

For both “Zone Deviation” and “Buoy Deviation” if the boat is TOWARD the skier by more than 20cm a mandatory reride will be awarded. The skier can improve. The score is not protected. The skier may decide not to take a reride and accept the score that was achieved within tolerance.

If the "Entry Gate Deviation" is more than 20cm to the left or right of centerline a mandatory reride will be awarded. No protected score.

The "Cumulative Deviation" will be considered out of tolerance if it is greater than the values in the below table. Just as with Zone and Buoy if the boat is away from the skier then an optional reride will be awarded. The skier can improve. The score is protected. If the data shows the boat was toward the skier a mandatory reride will be awarded. The skier can improve. The score is not protected. The skier may decide not to take a reride and accept the score that was achieved within tolerance.

Bouy	Cum Tolerance
B2	28 cm
B3	35 cm
B4	40 cm
B5	45 cm
B6	49 cm

How many rerides can I get? "There shall be no more than one mandatory reride for boat path deviation in a single pass. If during the mandatory reride the boat deviation would require another mandatory reride then the score given will be the maximum score in tolerance on the reride pass. No reride. In this case the Chief Judge shall warn the driver that the driving is not acceptable, and the driver may be replaced."   (official WSC text) 

If the path deviation is toward the skier the reride is mandatory. If it happens a second time there will be no second reride. The skier will receive the highest score before the deviation.

If the path deviation is away from the skier there is no limit to the number of rerides per pass.

 Aditional "Zone" Minutia: the “Zone Deviation” data captures the point where the boat is most toward the skier. An example of how this might be counterintuitive is if the skier is at one ball and the boat is to the left of center (away from the skier)  the “Zone Deviation” number will the point where the boat is farthest to the right.  Don’t let this detail hurt your brain.  The rules for your reride are still dictated by deviations greater than 20cm as detailed above. 

Additionally, The "Zone Deviation"  data is not even displayed in the boat unless it is more than 20cm off-center.

The text above is an attempt to simplify the new rules. PLEASE refer to the official rule book for more granular information.  

 

[ALPJr]

Thanks

[disland]

Are the rules enforeced no matter speed or line length?

 

[Horton]

@disland

the official text is in this document

https://www.ballofspray.com/forum#/discussion/24987/iwwf-waterski-council-releases-meeting-minutes

[Horton]

if anybody's still confused listen to this episode of DFC https://www.ballofspray.com/forum#/discussion/25020/distance-from-center-episode-45-boat-path-measuring-systems

[JackQ]

I believe the tolerance's need to be reviewed and possible modified as we gain more real world experience.

 

I doubt there was any science in the 20cm max or cumulative deviation, it was originally developed for video review.

 

One could argue that when a strong skier (Freddy, JT , CP, etc) gets in trouble a driver may struggle to keep within 20cm, but Ok on the other buoys and with the cumulative, and the skier did not gain advantage. I also believe only one mandator re-ride, is an unfair penalty to a skier for sub optimal driving.

 

Experience should dictate if they are too restrictive or too loose. After a season experience we may find 20cm is easily obtained and it should be 17cm or 19 or ??

[Horton]

@JackQ 20cm is almost 8 inches. No matter the skier a top driver in a decent should be able to stay within 8 inches.

 

20cm is the tolerance. It is simply the agreed upon standard.

 

There is only one allowed re-ride when the driver is out of tolerance toward the skier to prevent driver from attempting to weave with the skier.

[Drago]

Can't wait to watch a webcast @ Moomba or any other difficult lake or conditions.Like watching an NBA game when they continually fake fouls and shoot free throws all night.

[Horton]

@Drago you realize that the only way there can be more than one reride per pass as if the driver is out of tolerance against the skier? There can't be very many rear rides unless the drivers are evil and or totally incompetent. I don't think there will be very many rerides.

[Bruce_Butterfield]

We need to pay attention to the wording: "There shall be no more than one mandatory reride for boat path deviation in a single pass."

 

So if a driver is pulling someone like a Mike Kjellander, gets nailed out of tolerance at 1 ball at 38, then good on the re-ride, gets pulled out at 1 ball at 39, then good on the re-ride, gets pulled out at 1 ball at 41, then good on the re-ride, then gets pulled out again at 1 ball at 43, then good on the re-ride. There is definitely the possibility that a skier could get 4 mandatory re-rides in a set.

 

So for place like Moomba with a strong current, others with a strong crosswind, a "bad boat", or a mediocre driver, things could get interesting. Yes we will learn alot this year.

[Chad_Scott]

The one re ride was established by the IWSF. It was based upon a situation that has already occurred where a skier had multiple opportunities at a world record attempt due to boat path. Keep in mind that the 20 cm is towards the skier. So as Horton pointed out. That’s nearly 8 inches to the favor or the skier. It’s 20 cm left and right of center line. So it’s a lot of room This is an opportunity for the organizers to place the best drivers in the boat and make sure the right guy is in the boat and take the politics out the equation.

[Horton]

@Bruce_Butterfield possible? Yes. Probable or likely? I think not.

 

I will wager one bottle of single malt scotch or the equivalent in IPA that your scenario of three or more consecutive mandatory BPMS Rerides will not happen at any class L or R tournament with a senior driver at the wheel in the next 12 months.

 

 

 

[The_MS]

I believe that after this summer you will see WR or National R capable skiers be really picky on which events the compete at. IMO, there are very few drivers that have the ability to drive a path that is required with Sure Path. Sure Path will help drivers get better but is like skiing, very few people can run 41.

[Bruce_Butterfield]

@Horton I agree the scenario I put forth is unlikely, but is possible with less than ideal conditions - and you need a skier capable of running 41.

 

What I think is more likely is a bunch of heavy 55k skiers, say capable of running 39 on a good day, will have their scores reduced and/or multiple re-rides. There are a lot of L tournaments that don't have the elite level skiers OR elite level drivers.

 

And then you have guys like Mongo and JackQ. Pulling 30mph shortline for those guys isn't easy even for a good senior driver. I will bet that bottle of Scotch that they will have multiple re-rides.

 

Bottom line is we have a very tight tolerance that was generated and applied to world records (as is it should be) now applying to all L events for 38 and shorter. Is it too tight for less than world records and less than the handful of best drivers? IDK, but it will be an interesting year.

[klindy]

@Bruce_Butterfield i can’t argue your theory but in fact Mongo has submitted lots of records over the years and (most) have been approved. Point is, those records have been measured and are within tolerance. The difference now is he’ll have a chance to do it again if it’s measured out in real time AND he’ll know whether the boat path will pass before he even takes off his gloves.

[Horton]

@Bruce_Butterfield okay I'll take your wager.

 

I don't think that 20 cm per ball is excessive nor is the cumulative tolerance but I am prepared to be shown otherwise.

 

"Macallan 12" will be sufficient.

[Bruce_Butterfield]

ok @Horton , heres the bet.

 

A M7 or M8 skier will have 2 or more out of tolerance boat paths in a single round of Class L tournament in the 2021 calendar season.

 

With the change to require the IWWF "license", there may not be a decent sample to go by since it is a big question how many old skiers will choose class L. For this to be valid, there needs to be at least 10 Class L tournaments with M7 or M8 participants.

 

I look forward to the Macallen 12.

[Horton]

@Bruce_Butterfield

your original comment:

There is definitely the possibility that a skier could get 4 mandatory re-rides in a set.

2 or more is an entirely different bet

[Bruce_Butterfield]

@Horton you need to re-read my posts. I agreed that 4 re-rides was unlikely, but possible. The only comment I made on a bet was for the older/heavier guys to have "multiple" re-rides

 

"@Horton I agree the scenario I put forth is unlikely, but is possible with less than ideal conditions - and you need a skier capable of running 41.

 

What I think is more likely is a bunch of heavy 55k skiers, say capable of running 39 on a good day, will have their scores reduced and/or multiple re-rides. There are a lot of L tournaments that don't have the elite level skiers OR elite level drivers.

 

And then you have guys like Mongo and JackQ. Pulling 30mph shortline for those guys isn't easy even for a good senior driver. I will bet that bottle of Scotch that they will have multiple re-rides."

 

Simple math says that unless a skier is capable of running 39, there is no way he can get more than 2 re-rides anyway, so that's a very small group to begin with.

 

The real problem in my mind is not for the elite level skiers at elite level events, its for the multiple places that host L events with a handful of shortline skiers and may not have the world's best drivers.

[Horton]

@Bruce_Butterfield ok. Now i see your point. We will see.

[skierjp]

Not sure but the M7 and M8 would have to be at 38 to get a reride. Also, is that any speed or just 36?

[skierjp]

I’m not sure a world record is legal on a reride? I’m asking.

[Chad_Scott]

According to the discussions I believe a world record can achieved under the current rules proposal. @Bruce_Butterfield I had the opportunity to watch a couple of drivers pull Mongo at a tournament In November he was very close to breaking and even tied his national record. All of Mongo’s paths were in tolerance according to sure path. I have had the opportunity to watch the judges screen display for several tournaments in the southern region where sure path has been utilized and I think you would be surprised at the drivers performance. This will come into play when you have drivers at a tournament who don’t typically drive short line skiers and don’t have the experience to keep it in tolerance. I think this will encourage the LOC’s to put the best drivers in the events with the more skilled skiers. Keep in mind that re-ride potential is for beyond 38 off as I understand the rules. I could be wrong. @Bruce_Butterfield I know we have both been to tournaments where the best drivers were not allowed as asked to drive the events. Sure path will let you know instantly who should or should not be driving the better skiers. If I am the chief driver and I have a driver who can’t keep it in tolerance that driver will be replaced based upon live data. People have been hesitant not to pull a driver in the past. Now it will take feelings and friendship out of the decision. Screen says red over and over. Sorry but it’s time to replace you. Not your day today

[Bruce_Butterfield]

@Chad_Scott I think we are in agreement. A really good driver can keep Mongo in tolerance, but he will have to work a lot harder than keeping Nate in tolerance. A mediocre driver won't have a chance.

 

I agree Sure-Path is a good thing that will improve all drivers and weed out those not capable. I know more senior drivers than I care to mention that are past their weed out date. At the same time, there are good up and coming asst and regular drivers who will be helped immensely by surepath. They also need time behind the wheel in different boats and with different skiers. I just hope the fine line between weeding out the unqualified and using it as a learning tool can be balanced.

[Chad_Scott]

@Bruce_Butterfield agreed. But should people pay money to ski behind mediocre drivers if there are better ones available. New up and comers that don’t get in the boat because of the politics of driving. I think the up and comers are going to welcome this technology and use it to get better. Personally I am 100% in favor of it. I do not want to even drive or ski a practice set without it. Great tool for skiers to see what’s happening during their good or bad set. Almost all drivers that I have introduced to it love it and want to use it. I think this will only give us all a better ride. It will also as you mentioned weed out some of the senior drivers that don’t drive and need to sit aside for someone that is working at it. This may be the tool to encourage those to give up the seat.

[sunperch]

Will sure-path be used at Nationals this year??

[hammerski]

Looks like the average using cumulative is 3.2” per buoy, about the length of my ring finger. This is gonna get interesting, can’t wait to drive with it! ?

[klindy]

@sunperch its not guaranteed until @JeffSurdej says it is, but I say it’s very, very likely. Sure path will be used at all southern region class L tournaments this year.

[klindy]

For all you folks who are concerned about the tolerances, they are the same. There haven’t been an over abundance of rerides due to boats path currently (yes there absolutely should have been more!).

 

@hammerski remember the cumulative tolerance is a “net tolerance” number so negative and positive numbers offset each other. Your comment implies that there is a max of 3.2” at each buoy if you score 6. That would be true if the boat was weaving down the lake equally at each buoy. However, the goal is (and the rules say) a “straight path”. So even if the boat was 8” off to one side and continued straight the net cumulative deviation would be 0” and, since no single buoy was more than 20cm, the boat path would measure “good”. Clearly that’s not a decent boat path nor would it be expected.

[JeffSurdej]

@sunperch you betcha

[Horton]

apparently there is still a lot of disinformation or misunderstanding about these rules. I think my explanation at the top of this thread is pretty clear. if you're going to ski tournament this summer please read it carefully