ZO River Mode?

[Nick Sullivan]

Hey Guys,

The guy that just purchased my boat will be using it on the Columbia River. Someone today mentioned that there is a "River Mode" for Zero Off. Is this true and if so how does it work?

 

Thanks!

[Ilivetoski]

GPS based speed control does not work on moving water. The guy who had our Malibu before us was about to get SG but called PP (PP owns SG) and they told him that SG or ZO will not work on moving water (he skied on the Ohio River)

[Nick Sullivan]

Yeah I know that, that is why I was so suprised today when these guys where telling me Zero Off has a River Setting. I couldn't grasp how that would be possible.

[Chuck_Dickey]

Unless the river is really bookin' why does it matter. With PP you would have to adjust RPM same as Head/Tail wind. ZO will give actual times regardless of current speed. Like at the Mooba Masters on the Yarra River in Austraila.

[mlange]

I don't see it documented in the Rev Q user manual, but I swear I saw it on the setup screen when I was poking around ZO in the boat the other day trying to learn my way around better.

 

I'll see if I can get to the boat today and check it out.

 

Mike

[Sethro]

My understanding is that you drift to get the speed of the current, and then let ZO know to adjust accordingly by telling it whether you are going upstream or downstream. So you have to change a setting each time you turn around. I thought I remembered it was a "Nautiques only" option when it first came out, but I assume that has changed by now??? That info was from a couple of years ago, so I don't know if it has changed.

 

PerfectPass StarGazer has a river mode software option that you must ask for specifically. It works with systems that utilize the paddlewheel (systems upgraded from pre-Stargazer times typically) and simply "shuts off" the GPS input and "turns on" the paddlewheel input for speed readings.

[DanE]

Since the rulebook states that "speed over the bottom" is what counts, why would a current interfere with a GPS speed control?

[SkiJay]

I think there was a River Mode in the very first version of ZO, but it was a recreational thing and I think it's long gone, so here are four things to consider.

 

If skiing in a slalom course in a river, you have to get used to skiing at two different water speeds. That kind of sucks, but the pros deal with it annually at Moomba. Changing the ground speed so that the water speed is correct would invalidate the elapsed time of the pass, which is pretty much pointless.

 

If freeskiers want to practice at a constant and legitimate water speed, they can achieve this manually. First establish the current speed by drifting downstream with ZO, or some other GPS, turned on so it can measure the ground speed. Then ski in Rec mode, adding the current speed to the skier's target speed for downstream passes and subtracting it for upstream passes.

 

If the skiers have ZO settings they like (B2, C1, etc.), set that in Tournament mode before entering Rec mode, because the active pull setting when you enter Rec mode remains active.

 

Finally, consider turning down the stationary volume so all of the beeping that ZO does while making these changes doesn't drive everyone in the boat out of their minds!

[A_B]

I am with Dan. The speed between the buoys or over the bottom is fixed, so if you want to run a set speed, ZO will do it. Under PP, or rpm based speed, you would pickup speed with the current and lose speed going against it.

 

I would run in REC mode if you want to adjust by small increments, or just leave in Tournament mode. You would be running actual speed over the bottom of the river or set distances.

[Mateo_Vargas]

I remember seeing River Mode in my friends 2010 Nautique when changing the wait timer and also curious how it works. I do some skiing in currents and know trick speed has to be adjusted when going upstream or downstream with ZO, the PP paddle wheel worked great for this. I can see jumping downstream to be a big advantage due to the added speed of the current.

[GAJ0004]

If you have the version of PPSG that uses the paddle wheel sensor, and course magnets it will work in a river.

[Ilivetoski]

@DanE think of if you are in an airport on a moving sidewalk. If you are walking on the ground next to it, you are walking at normal speed. If you are on the moving sidewalk you are moving faster because the ground beneth you is moving aswell. Vic versa if you try to walk against the way that the moving side walk is going, it slows you down. Same concept for river skiing with ZO, at least that is why it would make it go faster, tournment mode ZO has no adjustment for possible conditions that would change the speed. It assumes that you are on some body of water (normally private) that will be constant, not moving.

[DanE]

@livetoski Yes I do understand that the water is moving but the speed measured is speed over the bottom, now the bottom of the river doesn´t move right? I just assumed since ZO use GPS to measure speed it would keep the speed over bottom constant regardless of river current.

[A_B]

I think that happens when you use a speedometer or rpm based speed control.

 

If you have a top speed of 50 mph and go with a 5 mph river current, the boat would register 50 on the speedometer, yet a gps unit would give you a faster speed over the bottom and register 55? It doesnt care about the current and measures speed over the bottom, which is what you want. I think.

 

Should be easy enough to determine. Just run against the river current with ZO set on a speed and see if the rpms on the tach are higher or the same as going with the current. Would be interesting to see the results.

 

I am in a private lake, and we don't have a current, but we do have wind, which can act the same as current, and I assume ZO will make the same adjustments as it does when it is headwind/tailwind.

[Sethro]

I am going out this morning on my friend's new TXI with ZO, and we will be on a river. However, in our drought conditions the river is barely flowing, so it will be interesting to see if there is a measureable difference. In addition, I can't yet ski recovering from my cervical fusion surgery, so I will be driving only.

 

I will keep an eye on the RPM's during up/down passes to see if there is a difference holding the set speed. We've always used a paddlewheel PP system for tricking, and of course the RPM for slaloming, so I should know right away. Always been a difference in RPM's for up/down passes for non GPS systems.

[ForrestGump]

River Mode is an optional enhancement. If you don't have it enabled, you have to send the head unit to ZO and they'll add it. As far as I can remember, it's really geared to tricks and wakeboarding and not slalom.

 

When River Mode is enabled, an estimate of the speed of the current can be entered, and the driver can then add or subtract this speed offset from the baseline speed setpoint (add when riding with the current, subtract while riding against the current) while making his turn with a single push on the SEL button. The intent is to allow the driver a simple single adjustment means of maintaining constant speed over the water with or against currents. This function only operates from the tournament screen where the two additional selectable parameters (river current speed and an UpRiver/DNRiver icon) show up only when this option is enabled.

[popof]

Hey Guys! Interesting topic! My name is Romain and I ski in Paris on the Seine River. We do have a Slalom installed and despite adverse conditions we try to get the most out of it.

In deed the current (or stream I don't know which word should be used) affects your skiing and your speed over the course. Everything that's been said earlier in this topic is true, it is exactly as walking on the Airport's moving sidewalk.

Though people tend to not really comprehend how this affects "since speed over bottom is what counts", let me try (I said TRY) to explain it to you graphically.

When you are going down stream, if you have a perfect pass, it'll give you the correct speed over the course, but with the water-feel of lower speeds. For instance, if the current is (as an example) 2mph, and you're skiing 34mph, then the water will feel as it usually does when skiing 32mph.

When you're going upstream it's the other way around.

 

If this is not obvious for you, try to imagine it with and EXTREME current (in your mind).

 

Imagine the current is 34mph (I know it's not realistic, but just to help you understand), then, the Perfect Pass would detect an already given speed of 34mph, and set the boat speed to...0mph. (Downstream).Good.

So you would have to ski the course while being pulled by a boat travelling at 0mph... Said differently you'd be swimming your way through the course with lifejacket and ski on, while the boat peacefully drifts at 34mph down the main buoy channel.... See how this could be a problem?

Well the same thing but less exaggerated happens when you're skiing downstream. When you're going upstream it's actually the other way around, the water feels harder, you get better response from your ski and plenty of time to get to the next buoy.

 

I don't know for the other rivers but what affects us most is actually not the stream, but the profound "rollers" or "regular bumps" (forgive my lack of vocabulary) that form perpendicular to the stream as often as a really big boat cruises by, and that take for ever to settle. I have noticed on my personal experience that skiing at 32mph on the Seine river equates to skiing 34mph on any quiet closed lake.

 

Skiing 34 on the Seine River where we ski is almost impossible needless to say 36....

[east tx skier]

At one point, there was a version of the PP SG software that had a "river" setting in it. You had to specifically ask for this version of the software though. When engaged, it basically cut GPS out of the picture and took the speed input from the paddle wheel.

 

When we are on flowing water, we just guess the speed of the current and run in GPS practice mode with the speed increased or decreased to compensate. This is free skiing though. In the course, it technically doesn't matter as far as speed control goes. In the course, you're timing speed between two fixed points, i.e., speed over ground. So the GPS can do this regardless of current.

[LeonL]

@east tx skier, you've got it! ZO will pull selected speed regardless of current (within reason of course) and go from entrance gate to exit gate at 16.95/16.08 etc. The way the ski feels under you is another thing and not germane to this subject. ZO doesn't care about current, it's driven by earth coordinates -- Latitude and Longitude.

[Sethro]

That's fine, if you have a course on the river. We only have a course at our private site on a lake, but we do a lot skiing on the river as well. Trick skiing is actually the bigger concern for use while using ZO on the river.

 

As expected, the river was only flowing about 0.4mph, according to ZO last weekend, so I didn't really see a difference up/down stream. If I was able to ski I could probably have felt that difference on the trick ski.

 

However, the real problem was that we didn't have the manual for ZO and I couldn't figure out how to get in recreation mode anyway. So there was lots and lots of beeping during the slalom runs.

 

On a postive note, both women we had skiing said it was the nicest wake they had ever skiied. One was 15off, and the other 22 off...both at 30mph. Both commented how the boat had no give when they turned...they are used to PP.

[Chuck_Dickey]

http://www.zerogps.com/wp-content/uploads/zerooff_quickstart_manual.pdf

 

This laminated printed version came in my owners manual.

[I5boi]

@Sully‌ did you find what you were looking for? Please share as I am further down the river. No pee please; Hanford does well enough.

[Dacon62]

Page 68 of this excellent Zero Off overview shows river mode. Looks like only for tricks??

Slalom guys...laminate page 30 to keep in the boat glove box. Great visual of how the different letter/number settings affect the engine response curve to load applied.

http://www.usawaterski.org/speedcontrol/zerooffpresentation.pdf

 

[GOODESkier]

On the Columbia River, using GPS speed control makes the RPM really noticeable. Headed up river, RPM's are cranking (working hard to travel 34.2 MPH across the bottom of the river bed). Headed down river and the boat turns what is almost silent as it doesn't have to hardly work to keep that same speed. Interesting at the least. Makes backing up a hard pass even harder sometimes! The Columbia is an unforgiving site, especially at 41 degrees water temp right now!

[MattP]

@Dacon62‌ hmm it could be for only tricks because you map a course for slalom and jump for times and not for trick.

[Chef23]

How do they handle the current at Moomba?

[MattP]

@Jody_Seal‌ you drive there whats the story?

[Sethro]

I remembered this thread, and see it's still has an open question about Moomba and the current. I didn't quite understand that ZO was adjusting speed based on a set distance until reading this thread again. I always kind of assumed it was adjusting to skier input based on the speed at which it was set, and timing it in the process. So, ZO is adjusting for the current by default as long as it's in a mapped course. Hmmm.

 

We now have two ZO boats and a PP Stargazer boat in the rotation. So trick skiing on the river for us means adjusting for the current and it's a bit of a pain. It's amazing how much the current varies from one spot of the river to the other, and yes it's quite noticeable on the trick ski. I much prefer my boat with the paddlewheel for river skiing.