How you throttle the Zero Off boats for slalom

[robscholl-OF]

This weekend at a tournament one of the drivers had issues with the 2009 Malibu LXI surging and running up into the course.  I had driven the boat for several classes prior to include Mens 1 and all the women classes.  The speeds I pulled ranged from 28 mph to 36 mph and 15 off to 35 off.  I had absolutly no issues with the boat whatsoever.  I made the comment on the dock that I have never had problems with any of the Zero Off drive by wire boats to include MC, CC and Malibu in slalom, tricks is another matter, but I have that figured out now.

I then said I had early on been told by a very senior driver that once you come off the island and the boat is straight, to push the throttle forward nice and smooth until it stops.  I was told, DO NOT EVER STOP while pushing it forward as it can cause the boat to surge if you stop and start throtteling again.   When I said that it seemed like I had just said bad things about everyones mother.  I then found out that is not the way most of the drivers that were present on the dock, do it.  They push it up till it beeps that it is at speed and then leave it.  I am a rated driver and have driven at several tournaments this year.  I have pulled every class from boys and girls 1 to men and women 8.  I have not had one re-ride due to driver or boat issues this year.  I also have to drive for Richard Doane (Ball of Spray regular).  We have Stargazer on our boats and they are not drive by wire, so this is never an issue for us in practice.  Sorry about the long post, but am I one of the only ones who drives this way?  It seems to work well for me.           

[ForrestGump]

I have been told from the very beginning that you should run the boat smoothly up to full throttle. That ZO can only control up to the amount of throttle that you leave it at. So if you ran it up to 50% throttle, even though it was engaged, 50% throttle is the max that ZO could command.  Now, I've never stopped adding throttle and then pushed it forward so I can't comment on what happens if you do.

[scoke]

 

Posted previously:

This past weekend we skied behind ZO for 6 rnds in a tourney, all on a 2008 Malibu (we thanked poster TeamMalibu several times as he was generous enough to allow us to use the boat the whole weekend.)The boat skis great, feels great and the ZO was fine.

Ironically it was also the first time I have seen any ZO issue to me personally (only have heard of 1 other Malibu-ZO issue and it happened to my ski partner; might have been throttled not enough as well). It's a sorted affair as there are quite a few things that could attribute to the issue that arose: the ECM, Indmar, the throttle and the driver.

The boat was a 2008 RLXi with ZO recently added to it. The setup was a straight in setup, not excessively short, at Olde Oaks. The throttle was the older(2008) version that it's range of motion seemed shorter compared to other boats, say a Nauti or MC.

The driver pulled me up heading to the greens. The boat felt a bit slow as i settled in to pull out. As I pulled out, the boat slowed down then accelerated at the same time. The whole pass my timing was a bit off as we were over rev-ved at the gates. We decided that the throttle must be pushed pashed the threshold a bit more than previously done, especially at 36mph. The drivers standard boat is a 2007-MC with SG so it's throttle is different and has a different application.

After that pass, we never had another issue and we had come to several conclusions:
get the boat up to speed quickly to engage but dont just blindly bury the throttle
once the boat locks in, then push the throttle 25% more past the engage point (on our 2007 Nauti, after it engages, we bury the throttle to the floor and have never had an issue).
ZO must be driven differently from SG
if the throttle is buried quickly past the set point from the beginning, it can over-rev.

Just a side note, it's interesting as 2008 Malibu had some throttle and electrical issues being worked through as well as a non E-Controls ECM, most likely Delphi(?). Then add in Zero Off to the mix with a new ECM and the result could be some rare bugs or rare operational occasional glitches.

scoke.

[eleeski]

Stan's lake is not short. I smoothly acelerate the throttle until it beeps and push it some past that (25% seems right) - but never to the stops. There is plenty of phantom throttle left to pull slalom. I have never gotten bad times or weird pulls with that technique.

I have not driven jumpers - I would smoothly push it to the stops for a long jumper.

Tricks is like slalom,  just a bit past the beep is plenty. But I hand drive the turns to give a good double up. Even after the beep, I don't advance the throttle for the double up to keep any overspeed to a minimum. Once clear of the double up I advance the throttle (~25%) and the boat moves just a bit before quickly settling in. Sorry about the long divergence into tricks but the speed response to inadequate throttle advance should be similar for slalom. There, but minor once the correction is made. Just make sure there is enough phantom throttle for the load BEFORE entering the course.

DBW Stargazer and DBW PP are totally random about aquiring speed. I drop well below the aquire throttle in the turn and pray to aquire once I line up with the course. Often (~10% of the time) it does not aquire for tricks. The UCSD boat is more like 60% of the time missing for tricks and 20% for slalom. Lots of hand driving. No wonder I like ZO - it actually and reliably aquires speed.

Eric

[JohnN]

Like you I've driven a number of events with ZO from B1-M?  With the kids I usually pull them up then go about 25% past engagement (I think?).  With the 34/36 mph skiers I just smoothly roll it to the stops to give it all its got - power is usually an issue at elevation these days.  Seems to work every time and is such an easy system to drive.

John

[eleeski]

I'm not a rated driver so my experience is all in practice. Lots of hours and the freedom to mess with things to see what works best.

People seem to like my driving. Maybe because it keeps me from holding the release in tricks (note that I said holding not releasing - you'd better try really hard to stand up those tricks with me). Or maybe it keeps me from giving bad coaching advice in slalom.

Eric

[GAJ0004]

I throttle the boat up quickly to the setpoint on perfect pass or Zero Off.  On a mechanical version of Perfect Pass you have to be careful not to overshoot the speed by too much. I concentrate on giving my skier a smooth pullout, and I just wait for Zero Off to lock in.