A Zero Off Myth (or least I think it's a myth!)

[Than_Bogan]

At a tournament this weekend, I was talking with someone about ZO settings, and I said I was using B1.  He said he was using A3, and then said something like "which is almost B1 anyhow."

I didn't think much of it at the time, but that's wrong -- isn't it?  I think it reflects the myth that the settings are just 9 stops along one line, i.e. A1, A2, A3, B1, B2, B3, C1, C2, C3.

But in fact (according to information gathered here and linked from here), the letter and the number are two independent parameters.  So B1 vs. A3 is almost as different as you can get (with only C1/A3 and A1/C3 being further apart).

It would be much more accurate, when considering similarity, to think of it as a square:

A1 A2 A3

B1 B2 B3

C1 C2 C3

Right??

And I don't think this is a purely academic consideration, as it effects how one should experiment in finding a setting.  If B1 seems pretty good, but you're still experimenting (as I am), then the ones to try out would be the neighbors: A1, C1, and B2.  Similarly, if you want to get a feel for the range of parameters, you'd want to try the corners: A1, A3, C1, C3.

If you (incorrectly) think of it as a line, it will be harder to figure out what to try and how to understand your results.

So let's spread the truth on this!  (Unless this isn't the truth...)

[clemsondave]

I'd say A1 and B3 are very different. A1 would be a delayed, soft and long pull. B3 would come on a little earlier, be harder and shorter.

 

If you want the pull to come on sooner go from A --> C

 

If you want the pull to be harder go from 1 --> 3

 

I'm on C2, except on the MC I go C3 since I feel it is a softer pulling boat.

[scoke]

 

Very much a myth; math is math.

 For your reading pleasure:

My 1.0 charts and a great thread:

 

http://www.thewaterskiforum.com/webbbs/images/main/pic55788.gif

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 Cemsondaves perception and generation 2.0 for the engineering inclined:

 

http://www.schnitzskis.com/images/626_Daves_ZO_Chart_A.jpg

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

and I piled on a bit as the engineer geek in me couldnt resist talking about moments and areas under curves:

 

http://www.public.iastate.edu/~fanous/ce332/displ/img/2scfinshemo.gif

 

 

 

 

 

 

 

 

 

 

 

Personally I ride C2.  Couple of weeks ago after feeling a different boat, I came home and tried nearly all of the settings in the same set. Ran about 10+ 32's to feel and hear things out. It was obvious on the different settings how easy it was for me to get out of Sync with the boat vs how much I needed and didn't need out of the buoy. Came back to C2 at the end of the set.

 

[Horton]

Scoke,

I cleaned up your post a little. Hope you do not mind. That last graph? What the heck is that?

[h2odawg79]

Wow Scoke! That is very cool. Of course I am with Horton on that last diagram. (That is freakishly Geeky man!)

[scoke]

 

 

From my original post all exlpanations and definitions are here:

http://www.thewaterskiforum.com/cgi-bin/bbs53x/webbbs_config.pl?read=55690

 

 

[clemsondave]

Any way you draw it, I believe they need to be smooth curves. RPM's cannot ramp up or cut off immediately.

 

Too bad we cannot get ZO to comment on these. They are the two most popular theories I've seen.

[Than_Bogan]

I actually think it's bizarre how little information ZO seems to be giving out.  In order to actually build a control system (using the formal meaning of control system: http://en.wikipedia.org/wiki/Control_system), they obviously must understand exactly what each parameter controls.  So "surely" it must be possible to provide at least enough information that someone else could then take it and make a readable presentation out of it.

Most likely, this could all be spelled out very precisely using standard control system terminology.  I'm not saying that, in and of itself, would make it much easier to decide what setting to use, but it just seems weird for them to be so vague about what these parameters are.  It's not as if control system theory is a brand new field or anything!

The only explanation I can think of is some Intellectual Property concern, if they don't have good patents around it.  Then giving out too much detail would make it too easy for a competitor to copy it.

[Than_Bogan]

scoke -- from that post I don't find a description of what the axes mean, nor what A,B,C, and D are, nor what the dotted line represents.  And while there are more posts in the thread, the interface of that forum seems too challenging to navigate for my lazy ass.

[Than_Bogan]

Also, I hate to criticise any chart when I'm waaaay to lazy to make my own, but I'm going to anyhow :)

I think I'd want any chart of what the boat does to be centered (in y) on the average RPM, and thus show what it's doing both when more RPM is needed and when LESS RPM is needed.  Then I'd want to see one full period -- i.e. the entire cycle from one point in the course to the next corresponding point.  It's possible to interpret Dave's charts in that way (as the ends are at the same RPM level), but scoke's charts for A and C do not have that property, so there is some missing information about what happens next.

It would be my expectation for the RPM over a period to form roughly a Sinusoid (i.e. ramping up and down very smoothly), which neither of the presented charts suggest.

Oh, and for those who accused scoke of being a geek, you ain't seen nothin' yet! :)

[scoke]

 

Great! I look forward to hear about your hours of testing, research, interviewing shortline skiers, riding in the boat with shortline skiers, your thought process, graphing and results for the 3.0.

scoke.

 

[clemsondave]

Here is my description, copied from Schnitz's website. Goes with my chart above (one with the bell curves). For RevQ.

 

Here are my thoughts. It is much more complicated than the below, but in it's simplest terms, here is how I interpret the ZO descriptions. The boat is constantly trying to stay at a steady speed, but for this discussion, I am keeping it simple.

 

The problem I have with ZO's descriptions is that they reference 'when the skier rounds the buoy.' Well, we all round the buoy at different times and usually different times at each turn. We also all load the boat at different times. Some load right out of the turn, some don't load until behind the boat.

 

For this reason, I reference the 'moment of load.' The boat does not know to do anything until it senses it's speed slowing down. This 'moment' could be right out of the buoy, behind the boat, or free skiing. It's just when you start to slow the boat down. Once that moment of load occurs, the boat must compensate by increasing RPMs. How it does that is where we get the ABC123.

 

The letters (A, B, C) are the difference in time where the boat starts to increase RPM. 'A' will have the most delay and 'C' will have the least. This means at the moment of load, C will start increasing RPMs the quickest, while 'A' will have the largest delay.

 

The numbers (1, 2, 3) are the intensity and duration of the RPM increase. '1' will have the smallest amount of RPM increase, but for the longest duration (long and soft). '3' will have the highest RPM increase, but for a short duration (short and hard).

 

Some examples:

 

A1: Will have a delay after you start pulling. It will have a long soft pull.

A3: Will have a delay after you start pulling. It will have a short hard pull.

C1: Will start pulling right after you do. It will have a long soft pull.

C3: Will start pulling right after you do. It will have a short hard pull.

 

 

Please note that this is my theory from my experience and talking with others, which has not been confirmed by ZO. I welcome input from everyone.

 

I have not pulled enough skiers to recommend one setting for a certain style yet. We are all experimenting at the moment. I can tell you that as a 'new school' skier, I do not get wide enough with the 'C' settings. I seem to get the earliest and widest with A3, but I am not in good enough shape to hold the pull sometimes so I usually end up on A2.

 

Another case we ran into yesterday. Skier (on A2) was making a good turn, pausing, giving up some angle, then accelerating. It looked like what would happen with the ski turning too hard, but it wasn't. We moved him to C2 and it completely went away. C2 picked him up earlier, which for him, eliminated the pause.

 

Below is a graphical representation. (see chart above)

 

The vertial plane for each curve is the amount of RPM increase. You can see that the '1s' will have the least RPM increase and the '3s' will have the most.

 

The horizontal plane is the duration of the RPM increase. This is not representing any buoys. Remeber, different people pull at different times, intensity and duration. It is a general time representation from the moment you start pulling.

[Than_Bogan]

scoke, dave -- would either of you be willing to whisper me your email addresses?  I think I want to take this discussion to a level of geekiness that may cause physical harm to the less geeky :).  Then perhaps if I/we can make sense out of these thoughts swirling in my head, I'll eventually come back and publish something coherent.

I'm also starting to seriously think about videotaping the screen at various settings and charting the reported RPMs and speeds.  This would only be one input, because the information displayed is only so accurate, and may well be slightly delayed.  But one thing I think it WOULD reveal is whether the min/max RPM are different for different values, and similarly whether the min/max boat speed are different for different values.  I have my guesses, but actual recorded data would be a LOT more meaningful, even accounting for the display information probably being pretty noisy.

[h2odawg79]

Nothing delivers technical accuracy like crayons and a napkin!http://www.ballofspray.com/vanillaforum/js/tinymce/jscripts/tiny_mce/plugins/emotions/images/smiley-laughing.gif

[clemsondave]

Clemsontigerdave at yahoo

[Thomas Wayne]

"RPM's cannot ramp up or cut off immediately."

While this is technically true, that ramp can be damn short.  Get in a ZeroOff equipped CC 200, set the speed at 17.4 mph, and bury the throttle.  As soon as you're up to speed (17.4) start hitting the speed-up button as fast as you can.  The jump is acceleration is astonishing - you can hardly hit the button faster than the boat can respond.  Once you're at 36 mph, start hitting the down-speed button - when we did this on a test drive it was almost like pumping the brakes in a car.

Which brings me to:

"I think I'd want any chart of what the boat does to be centered (in y)on the average RPM, and thus show what it's doing both when more RPM isneeded and when LESS RPM is needed."

As hard as that CC 200 decelerated, I'm inclined to think the ECM actually forces an immediate drop in rpm sufficient for the prop to act like a drag brake.  I have no idea if that's actually how it's accomplished, but I'm having trouble imagining any other way to slow a boat that quickly.  What I can say is that it felt like we'd thrown a sea anchor out the back of the boat.

TW

[Than_Bogan]

INTERESTING, TW!  The mystery deepens.

[scoke]

 

TW: you are scaring me, that's exactly what we did initially on the testing and my exact thought process.

 

Rev X is Rev Q.

P101 was the standard. Rev X was floated out there, tested then adopted as Q.

 

[eleeski]

TW's regognition of the rapidity of the speed change may explain why repropping my boat made the pull so much better. With the new tall prop less HP was available to hammer my shoulders out of their sockets even with the same timing. Note that my old boat runs PP Classic.

Looking at the fancy graphs, the engine responses appear to be timing responses - not intensity responses. Stan's 08 jumps out of the water - there is lots of horsepower available to exactly fit the programmed curve. The CCs have a lot of drag at speed so less horsepower is available to exactly fit the curve. Overpulls or other form breaks take a bit longer to react to so the pull feels softer.

Perhaps Stan's MC needs to call for less throttle to respond to the loads. A slight change in the curve might exist but overall response will be similar - it will just feel better. I will try to get Will Bush up to Stan's to change that programming as an experiment. Will claims to have done exactly that to other boats - the downside he noticed was that tournament boats felt a lot worse. Of course, if we come up with a better throttle response that makes the buoy counts for MC better than for CC, I bet MC will adopt that for all their new boats.

Soft throttle plus a bubbler and we'll all be a pass better!

Eric

[jdarwin]

Since my tournament last weekend was the week prior to our Regional Championship, we had lots of folks trying to figure out ZO in the particular boat they had drawn at Regionals / Nationals.  One skier in particular (mid 39-off, 36mph) was trying to get the Malibu dialed in.  B2 was "a sponge" and C2 felt too strong.  C1 felt just right.  As the driver, I suggested C2 initially after B2 did not work.  He liked that it picked him up quicker at the buoy but felt too strong, too quickly.  C1 was the answer.  It picked him up quick at the buoy but there was a greater delay in returning to "base" speed and therefore didn't feel as strong.  I strongly believe in taking as many variables out of play and have stuck w/ B2 on all boats but I believe there is a difference boat to boat, brand to brand and to get the same "feel" behind each one requires an adjustment.  I'm fortunate that I drew Malibu in M4 since we have one on my lake and I spend a fair amount of time behind it.

One more thought;  we tend to ski each pass differently and with greater/lesser intensity which changes how the boat reacts to us.  As the rope gets shorter, we're skiing a different line and hooking up earlier and releasing earlier.  Therefore, what works at 28-off may not be ideal for 38-off.  Something else to consider.

[ForrestGump]

And that skier normally skis C2 or C3 behind the Nautiques.  In my case, I usually ski C1 behind the Nautique and liked B1 behind the Malibu. 

[LeonL]

As Darwin stated, things change as the line gets shorter.  Just to give you additional thoughts, you can change after every pass if want to.

[ktm300]

I have wondered if the increased RPM to run speed in the 2010 Nautique makes for a smoother pull. With the higher rpm it is more difficult for the ZO to make the same percentage change in RPM as a lower RPM pulling boat.

[ForrestGump]

The malibu hull has always seemed to have more "glide". I'm wondering if this causes the zo to roll the throttle back more on it's downward side of the rpm parabola. It'd be interesting to look at the rpm swings on the different hulls pulling the same skier.   

[clemsondave]

The other variable is the driver. How hard and when they counter-steer.

[ForrestGump]

Dave, I think this might be one reason why the 200s feel softer. They naturally track better and require less counter steer.  There's far less of a chance of the pylon moving away from the skier.

[Skihack]

The biggest challenge for us is getting the PP Stargazer on our 98 SN to feel like the ZO on the new tournament boats. My daughter practiced slalom today at the S Regs behind SN200 w/ ZO and skied 1 @ 28 off. That is about a pass less than she runs in practice. She is in G2 and never misses 28 off in practice. First thing she said about the SN200 is that it felt hard. Granted it did have a 6.0 and they will not be using that one in the slalom event. Wakes are very nice though. I've come to the conclusion if you are going to ski tournaments you are going to have to put out the greenbacks for a new boat with ZO. Or you are going to be in for continous frustration.

[A_B]

Whiner!! ZO will make her a better skier. Those other inferior systems have created a bunch of sissies.

 

Of course if you read my posts on this subject, you know I am being completely sarcastic.

 

I know a few long-time National skiers that have stopped going to tournaments, after like 40 years of Nationals. They have written several letters to USAWSA pleading to not go in this direction.

 

That are few exceptions to skiers losing several buoys or a complete pass when NOT training behind ZO and then trying it in a tournament.

[thager]

I have ZO on my 02 SN196 and I'm still down a pass or more but I now have nothing to whine about!

[clemsondave]

You will never make a 310hp boat (even with ZO) feel like a 343 or higher (6L) boat. IMHO, the HP difference is greater than the ZO/PP issue, especially now. I remember a couple years ago, during the winter I skied after taking a couple months off. It was behind an older Malibu with PP. Easily ran right through 35 and mid 38. Next day I put in my '08 196 - tried ZO and could barely got mid 35. I then tried SG (had both in that boat) and barely got mid 35. Guy I was skiing with had the same experience. After I got back into shape, I didn't have a problem.

 

It's not up to USAWS as to which cruise control gets put in boats.

[thager]

310 HP? Mine was a 330 Excaliber before the ZO conversion. Larger throttle body throat now than I had. I have a much stiffer pull than MS's 08 196 with the 343hp on A1. Probably the prop though.

[A_B]

True about USWSA, I told him he is wasting his time.

 

About the only way to get it changed is don't buy it.

[Boody]

Ok guys, lets tap the brakes here. 

1.  Zero off will not make you drop a pass.  Even if you aren't used to it.  If someone didn't ski well behind it, it just might the skier and not ZO.  There are just too many people that ski great behind it.

2.  As Dave said, you cannot compare an old boat to a new boat in terms of pull. 

3.  I am very active in the ski community, tournaments, etc, and have not heard such negative comments about ZO, nor have I seen people leave the sport because of it.  Assuming there are a few, that is by far the exception. 

4. Regional, National and World records are still behind set behind ZO.  Can't be too far off.

5.  There is more difference in how various lakes skis than ZO or PP.

6.  Rev Q works

7.  Rediculous comments like "Zero Off is killing our sport" is not helping to get this sport to grow.

8.  Zero Off is not going anywhere, might as well get used to it. 

9.  If you think you are going to ski crappy behind it, you probably will. 

 

[Skihack]

Boody,

What do you practice behind?

[skibug]

I will qualify my statement by saying that I am not a tournament skier nor a very good skier (32' off @ 34 MPH).  I am not a fluid skier, I am 200 #'s, and I pull off the ball.  My technique sucks more often than not.  I have skied behind 3 different boats with PP up until this spring when we got a new boat with ZO.  My average behind the 3 boats (2 SN, 1 Malibu) with PP was pretty consistant; even with the varaince in boats. 

Hands down, if you ski with good technique and you are early; then ZO should not be a huge issue......and here it comes; BUT!!!!  If you are late and scrambling it will punish you, no doubt.  The latter is more often the case.  This is not a whine, just an observation.  For the elite skiers, top end skiers with really good technique, and probably most women who are light on the line; it probably doesn't have as great an impact.

Unfortunately, now I have to agree with Boody's point # 8, our new boat and ZO are here to stay, so I guess I am going to have to get used to it.

[scoke]

 

Great post Boody!

 

For sale at a great price (going to list it on SIA.com this afternoon but posting it here first):

2007 Ski Nautique 196, comes with trailer

It's a white hull red stripe combo

Bimini top

cover with Nautique logo

new steering cable at the beginning of this season

new impeller installed in Feb and a new one can be installed at delivery

full tank of gas

oil changed every 50 hours

Hand cupped Acme 422 Prop (turns 3610 rpms at 36 and 3400 at 34)

Has Stargazer and Perfect Pass dialed in

Has Zero Off version Q as well.

 Ski a different cruise control system after every pass!

Listing it on SIA.com at $29k. Will deliver it within reason at that price.

 

[clemsondave]

I actually feel ZO helps me more than PP when I'm late. The key (and hard part), is getting into the correct position and not panic at the turn. When you do those things, ZO will give you a great pull to the next buoy. I agree though, if you are in a bad position, it can hurt you. I would encourage you, when you're running late, to take a deep breath, make a good turn and get into position before you start to pull.

[ski6jones]

I skied my first tournament the year ZO came out.

Once I found out I couldn't retrofit my older boat with ZO I decided not to ski in any more tournaments until I could get regular practice behind a boat with ZO.  That still hasn't happened.  My budget won't allow me to upgrade and there is one ZO boat out of about thirteen currently operating at our lakes. 

I'm not complaining.  I'm perfectly happy skiing with my crew and not skiing tournaments.

I just want to confirm at least one avid slalom skier not skiing in tournaments as a direct result of ZO.

[Roger]

We have a number of skiers at Okeeheelee that no longer ski tournaments due to ZO.

[A_B]

The one guy I am talking about is a senior judge, was skiing in at least 10 tournaments a season, including a zillion nationals. He pretty much could run 35 on all 10 different skis that he has in his garage, owns his own lake, BUT does not have a boat with ZO. His dropped a full pass behind ZO and didn't make his opening 28 off pass in one of the first tournaments skiing ZO.

 

The other guy is a BIg Dawg skier who has been In top 5 at Nationals quite a few times. He trains with guy #1 behind PP. I dint think he has run a 38 behind ZO in a tournament, when he was routinely mid 39.

 

Is ZO bad? I don't think so. Not being readily available is the bad part.

 

I guess if your baseball team played with titanium bats and then went to the state tournament and only wood bats could be used at the last minute, and the other team used wood bats all season, well, you get the picture....

[rmt15n]

We can all argue about the merits of ZO and whether it is good or bad.  The one thing that it has caused is dissension and that is the 1 thing this sport did not need.  Anyone who thinks 3 event skiing is not dying must be in a cave.  ZO has not helped the sport 1 iotta IMO.

[baumer]

For what it's worth I lurk and enjoy this site very much. I don't post much, but wanted to respond. Don't get me wrong I'm not knocking either system they both are good at what they do, but there are differences, can that be a good thing? I do prefer SG and am in a  position to ski behind ZO only during tournaments. I wish ZO would admin that there are differences then maybe this debate would stop who knows.

I use C1 behind SN200 and C3 behind Mastercraft still different than SG but close so it works and as long as I can ski my average that's ok with me.

Boody: I understand what you are saying though the experience that I have had is completely the opposite.

           7: Ridiculous comments like "Zero Off is killing our sport" is not helping to get this sport to grow. Maybe not but the way this ZO thing is going           it's not helping our sport either. Just my oppionon

How about the differences between PP and Accuski back in the day?

I guess it all relative the better we get as skiers the better we can adapt to the changes in speed controls, wind, water, temps, location, stress. 

[ForrestGump]

And yet every tournament I've been to in the last two years in the SCR is full with a waiting list.