Is there a Zero Off Easter egg?

[Horton]

@dirt are you trying to tell me something?

[Dirt]

@Horton No. The lighter skier is a lot lighter than both of us.

[Horton]

: )

[Horton]

I talked to someone who tried trick mode with a ProStar 6.2 today. Review was "Unskiable".

[Than_Bogan]

I heard the same thing from some folks in SC, although I can't remember exactly which boat. I know the engine they mentioned was a 6.something, though.

[Horton]

@Than_Bogan I'm pretty sure we spoke to the same knucklehead

[Milford]

Sounds like there is a reprogrammed ZO head unit being tested in Florida this week, where trick mode has all buoy timing enabled. All data is being captured via a laptop for further analysis. Initial reports are that times are good. More to come...

[ozski]

I gave it a try with the 196 6.0 and we used a light guy as a test dummy running -32 / 35 and he thought it was a bit like C3.

 

[CParrish43]

Well guys after all the talk about ZO in trick mode I had to go out and try it today and I gotta tell you I'm pretty blown away with the results. Hands down Nick P is excactly right about what the ZO does in normal slalom mode then down to trick mode. I got to drive my training partner today who is about my size and also skied with it so he could here the difference too in both settings. But there is a quick high roar but it's on and off you quick which I think makes a lot of senses why it feels better. Couple things that lead to that with really good results , acceleration and less line tension off the wakes out to the bouy. In normal slalom mode the ZO is on you longer and does not care where you are in the course , it has one job and one job only and that's get back to constant speed. Today I couldn't believe how much more speed I carried through out the course and how free of the boat I was and not feeling the ZO on me so hard out to the bouy. When you achieve that you're gonna be able to get the ski back under the line to center without the boat picking you up and you're gonna stay early and be way more efficient and keep moving better without causing unnecessary loads and forces.

The end result of this is really simple and that's more bouys , which leads to more confidence and then goals get achieved and the sport moves forward with some happy skiers out there. Guys I've already made some phone calls today and I'm gonna do everything in my power to keep pushing this and move forward. It's time to get some good mojo going back into our sport and time to make slalom skiing a little more easier on a upward swing. In my opinion slalom skiing the last ten years hasn't gotten any easier.

 

Cheers ,

CP

 

 

[Horton]

Ladies and gentlemen Mr. Christopher Parrish has spoken

[BG1]

What CParrish43 said! That’s what I felt with the original zero off and that’s what trick mode sounds like to me. When they added the ABC settings C felt the best but it was harder than the original for me. Then they added the 1,2,3 settings and it got even harder for me. This is not a knock on Zero Off because they were just trying to please the skiers. I only got to ski a short time with the original version in the fall but I remember thinking I would pick up 3 buoys by mid-season the next year. Then they added ABC/123 and I was down 3 buoys by mid-season instead.

[Ralph Lee]

Another Parrish prank

[Adam Caldwell]

Is anyone else out there using TrickMode on a 6.0 or 6.2L engine?

 

I pulled @AdamCord on a 2017 6.2L Mastercraft [rated at 430HP@5400rpm]. Ill let him respond to say how it felt.

 

For what its worth.....

Illmore reports peak torque for the 6.2L is 480lb-ft @ 4000rpm. The 6.2L MC runs a baseline of 4050rpm @ 36mph with 3-blade. Using a 2.7 Propeller-Curve-Exponent, the theoretical power output of the prop @ 4050rpm is in the ballpark of 250ftlbs -for this argument lets assume its close to actual. The delta between max-torque-output of the engine and its prop-torque-output at 4050rpm is roughly 230ftlbs (480ftlb -260ftlb).

 

Comparing the above to a 5.7L, [320hp@5000rpm Rating, with Peak Torque @ 365ftlb@4200] that runs a ~3800rpm baseline for 36mph, the delta between peakTrq and actual torque output will be down closer to 120-140ftlbs.

 

The additional ~100ft-lbs of potential toque output of the 6.2L vs the 5.7l (at 36mph rpm range) is significant and is exactly why @AdamCord felt what he did over the weekend. Without more tuning of Trickmode, there will be HUGE differences between how it feels on a 5.7 vs a 6.0 or other.

 

Ultimately for a given engine speed the delta between the engines torque curve and actual propeller loading/output defines how 'responsive' the engine will be to a signaled throttle input from ZO. All engines have more then enough power to swing us out there the way we want. The hard part is finding a cruise that will do it in a way that has a similar feel on each boat with all the different variables in the equation.

[CParrish43]

No Parrish prank , I wanna ski better and I want to see the sport as a whole ski better.

[Roger]

@CParrish43 - what motor is in the boat you tried the trick mode with?

[CParrish43]

We skied with the 6L 200 yesterday

[Bruce_Butterfield]

@adamcaldwell we have that same issue today with the current implementation of ZO that feels radically different with different engine/prop configurations. That is one of several causes of my ZO heartburn. Whether that problem is reduced or made worse in trick mode remains to be seen.

With any luck, as we get more skiers involved as opposed to just controls engineers who dont ski, the variation among engine/prop configurations can be significantly reduced.

[DW]

@adamhcaldwell : question, where are you getting the prop curve output data, from actual prop curves or some other source / estimate / calculation?

 

Generic power curves are available off the GM Powertain website.

 

[Adam Caldwell]

@DW, I use a 2.7 exponent up to a 3.0 to just get a feel for a theoretical prop curve. Given I don't have actual operating data for these boats - other then getting WOT speed/rpm and known RPM baselines for 34 and 36mph - but it does give you a feel for how much power is actually available within a performance window or operating condition. The additional factors to consider are hull drag, gear, prop size, pitch, cup etc, but IMO, in terms of "responsiveness" one of the big things to consider is the margin between toque output at 36mph and the ceiling of the actual engine performance torque curve. - I can send you a spread sheet if you like.

 

In reality though, all of these boats have MORE then enough power. We just need a more concrete set of performance tests to normalize the performance output of ZO settings between each boat manufacturer and their choice of prop,hull, and gear configuration.

 

For example, when an instant 900lb drag is put on the boat, - all boats should be able to recover the speed setpoint within a maximum of 1.3sec (average time skier has to pull between buoy and CL @36mph), but not to exceed a minimum of .05sec (or whatever it feels like engine response is too fast).

 

With ZO, there are hundreds of combinations of gains/settings to achieve these operational performance targets, but at least there would be a physical standard and data set to be able to continuously improve and optimize the system year to year and take out the guess work.

 

Hell, maybe even require each company to perform DYNO runs simulating a slalom pass using ZO controls to get hard data to prove engine performance and response times are within an acceptable range/threshold. Hull drag would just be a factor within the final dataset to validate engine performance meets the "standard".

 

Once there is a standardized performance window for boats to operate within, then I think we will start to find more consistency in 'feel' between the boat manufacturers and implementation of ZO.

 

If this kind of standard already exists and boat tests with ZO are performed, then I am completely unaware. If there isnt, I would absolutely love to get started on the project.

 

 

[Horton]

@adamhcaldwell if the boats have enough power why are we focused on RPMs and props and such. Would it not make more sense to define standard acceleration/deceleration rates/limits and then let ZO and the ECM shoot for those targets?

 

(for the record I am aware that you are an engineer and engine testing paid your bills for years - I have a degree in photojournalism so if my questions is painfully stupid please be nice)

 

[Horton]

@rico the fact that you said

 

like @CParrish43 and @Horton said,

 

I might let you ski with me next year.

[DW]

@adamhcaldwell : absolutely, please, you speaketh my lingo, spreadsheets are great! To Horton's comment, who did you do engine development/testing work for?

[Adam Caldwell]

@Horton - Yes that would make a lot of sense, and is what our group of engi-neers at Denali (as @CaleBurdick likes to call us) are more interested in working on defining and testing. Ultimately however, RPM ranges, gears, and prop configuration does govern a significant portion of the boats ability to respond appropriately. We need to be doing both IMO. If we can figure out the appropriate accel/decel rates, then we would be better able to apply the tuning and logic to an electric powered boat - another item on the wish list....

 

To me, its one of those situations where - between drivers and skiers- we think we know what we want from the boat from a feel/sound/experience at all line lengths, but it doesn't mean its actually what we NEED for an optimal setup to cover all the different speeds and line lengths.

 

I know ski technology has come a long way, but I also think that one of the reasons the scores are much higher today also have something to do with the fact the boats have more power and response to throttle input with DI etc, but obviously we are still failing to harness the power we have appropriately. Data collection is the only way forward.

 

At longer lines, the skier gets pull more directly behind the boat as the rope doesnt get much more then 45deg to the pylon. A Strong boat, or a prop with too much HOLD will feel very stiff and unforgiving to them. But for a shortline guy, who is falling into the swing of the rope from a much higher (near 90deg) position, the high power of the boat comes on much more progressively, and builds with the skiers speed into CL. If anyone has ever played with super stretchy ropes will know how much it sucks to run 22 off on, but actually not that bad at 39/41 for the same reasoning.

 

Slalom is all about a transfer of energy between skier and the boat. For shortline, the only way to get enough energy to cast out around the turn and come back without sinking into a hole and running out of speed is if the boat is able to provided enough energy before we cross CL. A soft boat at longer line lengths can still do enough work over a greater distance & time to provide adequate energy to the skier to get through the preturn/turn. However, at shortline, the length of time and distance with which the boat can do work on the skier gets shorter - leaving the skier in an energy deficit to succesfully complete the turn. But put a soft boat into Trickmode where response times are faster with no programed delay and no throttle limit, and your back in business.

 

Imagine what would happen if the boat didn't pull/accelerate at all when we loaded the line. Yeah, it might feel slow and easy on your opener, but short-line scores will suffer due to the extreme lack of work applied to the skier before CL. It would be like trying to long-jump 20 feet with a 5ft long approach run - not happening. The energy must come from somewhere - and for us, its the boat.

 

Though we may not have it today, its entirely possible to have a boat feel and perform VERY well for both short-line and longline passes. I have nothing but respect for everyone who has been involved in ZO tuning, prop design etc, as this is an extremely challenging thing to do. I wish I could get involved somehow and be part of the next generation of control. @AdamCord and I have talked in detail about this, but well beyond the scope of this forum. Admittedly, I already deleted 4 or 5 paragraphs full of equations from this post alone... Maybe it would be a good GUT article to write up on the Denali site over the winter.

 

If anyone is interested, I have access to an engine testing facility here in Charleston with 20 test cells. We could setup an independent test and tune the ZO alogorithms such that each boat/engine configuration would perform to the bounds of a standard. Costs run about $2500/day of testing and between 50-75K per mo. No big deal right?

[CParrish43]

@rico and me , maybe coffee with me and @Horton then ski all together !!

[CParrish43]

Another food for thought. Why should a skier that becomes fit and strong be punished by ZO when .. key word when they are being pulled by a 400 hrp engine ?? @Horton @AdamCord

[Dirt]

I don't see any downside to this. As long as they keep the current settings and add this as an option, there should be nothing to complain about.

 

@CParrish43 I understand why you might want to ski and have coffee with Rico, but Horton. Really? Please tell me you were joking to make Horton feel good.

[skidawg]

Have coffee w/ Rico-make Horton get on a bike - he loves cycling

[Horton]

@CParrish43 you can have coffee & ski rides at my house anytime

[303Skier]

I got to pull @CParrish43 through some very short line lengths with and w/o trick mode. As a driver I noticed the boat never lost any speed. As soon as there was load on the boat it instantly picked back up in very short calculated bursts of acceleration. It was almost like the boat had 100 more HP. Aside from everything else it was very smooth in trick mode, I never felt @CParrish43 back there. I could literally drive the boat with my knee if I wanted to.

 

In conventional mode CP would pull the boat down drastically and then get hammered by a long period of acceleration. It's a feeling like the boat is struggling and didn't have enough power. I can also say driving the boat is harder. With guys like CP it's never very hard to drive but I noticed a huge difference between the two modes.

 

Also on a side note, I noticed CP was noticeable faster off the ball and side to side in trick mode. We all know what that means....

[Ralph Lee]

My ski season just started a month earlier!

[ozski]

Assuming a new setting is created, approved and released what does the roll out look like for the existing base of ZO users?

[303Skier]

@ozski you'd have to borrow a com cable and get the updated software from ZO. Once you have that it's a pretty easy upgrade. I have a video on how to do it on YouTube.

[AdamCord]

To @CParrish43 and @adamhcaldwell 's points these boats have tons of power. There is no reason why a bigger skier should be punished. The problem is that ZO programming is limiting the amount of throttle applied, so a bigger guy can slow the boat down, even on a 3+ setting. Then in order to get good times the ZO has to stay on the throttle long after the big skier comes off the second wake. This makes you narrow, fast into the ball and makes it near impossible to stay connected. Conversely a small skier doesn't pull the boat down as much, so the ZO can come off the gas as they leave the 2nd wake, making it easier to get high on the boat and stay connected.

 

It sounds like Trick Mode has no limit to how much gas it will give to get the speed back to where it needs to be. What this means is that someone like CP or Parsons will get the same speed swing from the boat in Trick Mode that someone like Nate might feel in Slalom mode.

 

It seems to me that a 3+ setting should be basically unlimited throttle response. If you run C3+, the boat should run nearly a constant speed when you ski. That may be really harsh and no fun to ski on, but then you can drop to B3+ or A3+ which will give a delay before going full throttle, which is what I'm hearing in Nick's Trick Mode video.

[Horton]

@AdamCord that is an extremely concise explanation of the way I understand it works also. ( odd considering that you are an engineer )

[MISkier]

I wonder how the Kd and clipping parameters from A3+ compare to Trick mode.

[jcamp]

Anyone have any guesses if PP Stargazer ZBox in trick mode will emulate ZO in trick mode?

[Milford]

@jcamp - that would certainly help move the sport in the right direction!  Cost of entry has been one of the biggest complaints, outside of the ZO quality of ride for larger guys.  What if a guy with a 15 year old boat could train on a public lake and come to nationals and crush it, because he is in familiar territory?  It really sucks that we have to spend so much $$ to stay current and that older boats that are not equipped with ZO offer such a different experience.

 

On another note, finally received some times from one of the pros testing with the modified head unit. These are the times that were gathered in Trick mode @36mph at -38:

70 one ball (perfect is 68)

78 mid course (perfect is 77)

08 end (perfect is 08)

 

For reference, this skier typically will get a 70 one ball time in regular slalom mode. Comment was that the boat felt slow...

[Horton]

@Milford soooo Parsons is not crazy?

[Milford]

Oh, he's crazy...but maybe just crazy enough!

[dchristman]

@jcamp zbox doesn't have the abc123 settings in trick mode.

[BG1]

The .02 second slow one ball time can be corrected by having the boat speed +.2 to +.5 MPH when it approaches the course. At least that has been the solution in the past. It is now +.5 MPH in slalom mode and even more with the plus setting. I would think it would take less over speed at the gates with Zero Off trick mode because the engine would be responding stronger.

[Dirt]

A guy I ski with tried it again today. He said it felt slower, easier and better.

[skierjp]

Crazy story. I skied this evening and on my last pass I had my wife put it in Trick mode. I never told her anything about this thread. We get to the end of the course and she's laughing. She ask me if I could hear the engine reving in the course. She could not believe the way it sounded. My boat is a 2017 Nautique 200 with a 6.2.

[Dirt]

@skierjp could you feel any difference? How much do you weigh and what speed/line length if don't mind me asking?

[Roger]

I tried it on my last pass Saturday. It felt really good to me, like a slow time. 34.2 -28 180lbs 2016 MC ProStar 5.7.

[CParrish43]

@Roger it feels slow because you're traveling faster and the boat isn't ahead of you now. You're getting free off the wakes with also added swing speed. A winning combination. When the mind senses that , it also slows down and makes thing feel like slow motion. Glad you liked it !!

[skierjp]

187lbs, B2, 34.2 just running some back to back 28s. Only skied a couple sets in the last 2 months. Definitely way more swing

[Wish]

Sounds like if this ever becomes a thing, it would separate the feel for PP users form ZO even more. Then again, I've always managed to find a ZO setting that feels better/easier then my PP. Still blows that ZO refuses to make a setting close to PP. I always hear.... "Oh, PP..well, that makes skiing easier and can add to your score so that doesn't count". Really? If it is that much easier, why not make it a setting? Seems the opposite direction in pull feel is being presented here as better.

[skierjp]

@wish, I'm confused. You complained about the ZO pull but then you say you've managed to find a ZO setting that feels better/easier then PP but you want ZO to make a setting close to PP???

[Wish]

I am guessing I am not the norm. Most PP folks do not like ZO or are doing what they can $$$$ to make PP like ZO. Shrinks tournament participation..somewhat. Off topic yes but why do folks say PP is easier? If it is, why not have that as a ZO setting? Rhetorical questions as it is way off topic. I whole heartadly agree that harnessing more swing speed from boat to CL is a better thing. Just wish some consideration was given to a large number of skiers not able to buy into ZO. Back to topic at hand.