How precisely does Perfect Pass hold speed?

I'd like to know how closely a Perfect Pass holds speed under various conditions in real life. This is for my DIY speed control project on our 1984 SN2001. I'd like to know what kind of accuracy is possible. I don't think the Zero Off would apply--it sounds like that's for drive-by-wire only, although I'd be interested in hearing about the Zero Off accuracy, too.

I realize the accuracy will depend on the model and engine. Ours is an '84 SN2001 with a PCM 351W and Holley carb. But again, I'll take whatever info anyone can provide.

The following would be an example of breaking out conditions. An answer for one line might be: "+/- 0.5 mph, but +/- 1.5 mph in wavy conditions" -- or something like that. The speed ranges are approximate and vary by rider...



Your Model & Engine: __________________



RPM Hold Mode

Cruising (indicate speed): __________________
Wakeboard (17-23mph): __________________
Slalom (25mph+): __________________



Paddle Wheel Speed Hold Mode

Cruising (indicate speed): __________________
Wakeboard (17-23mph): __________________
Slalom (25mph+): __________________



GPS Speed Hold Mode

Cruising (indicate speed): __________________
Wakeboard (17-23mph): __________________
Slalom (25mph+): __________________



Thanks in advance for sharing your experience!

Steve

Also I guess I just don't really understand the whole "cheap" cruise control thing. Is PP unreasonably expensive for the size of the industry, the amount of R&D, effectiveness, and safety of the product? I'd say no, and further I'd say let's support a company like that who has put so much effort into boat cruise control systems, particularly for the non DBW boats out there.

Thanks for the replies.

M3Fan wrote: PP and ZO in a slalom course care about timing primarily.

Only the Perfect Pass Star Gazer Three Event ($1,349) provides event timing. From the PP FAQ:

Q. We like to Wakeboard and run in a Slalom course but are not serious competitive skiers and do not care to time our passes. Which system is right for us? The Star Gazer Wake Edition has a great slalom mode that is GPS enhanced and very simple to use. This system does it all except course timing.

M3Fan wrote: It's all over the place, including a little hot into the gates in anticipation of the skier's pull.

Joel, can you define "all over the place", like how much +/- mph? Also, I assume you mean the driver sets the speed a little hot, as the PP has no idea it is headed toward the gate.

M3Fan wrote: So when you say accuracy do you mean pulling accurate times or holding a speed exactly despite varying loads and other outside factors (crew weight, wind, etc.)?

How closely it can hold speed, under the types of conditions I listed.

M3Fan wrote: Also I guess I just don't really understand the whole "cheap" cruise control thing. Is PP unreasonably expensive for the size of the industry, the amount of R&D, effectiveness, and safety of the product? I'd say no, and further I'd say let's support a company like that who has put so much effort into boat cruise control systems, particularly for the non DBW boats out there.

The same logic says let's shut down the Boat Maintenance and Engine Repair forums and take our boats to those fine marina mechanics, to support companies who have put so much effort into boat repair. Better not cut our own grass--there are companies who have put a lot of effort into providing great lawn care. You get my drift.

The point is... I bought the boat for my son and daughter. My son, who is 16 years old, has taken the initiative to help work on the boat. He's very into wakeboarding and desires better speed control. No, he doesn't have $1,195 for the PP Star Gazer Wake Edition (and we'd still have to install it). For a grand total of about $160 (mostly for the GPS sender), we can install our own GPS-based system. I'm trying to find out how well PP tracks so that we have some sort of goal in mind when we eventually get to playing with the pulse rates and control logic sensitivity.

Also... control theory is not new. Proportional-integral-derivative controllers (PID controllers) have been used for more than a century and are not very complicated. PP probably uses something similar (or simpler). I glanced at their patent US 5700171A but didn't see the control logic called out. I'm not minimizing their "R&D effort", but it ain't rocket science..... What I'll eventually determine is if a cheap automotive cruise control offers enough tuning parameters to hold the speed tightly enough for our use. If not, I'll still have a GPS speedo. :)

jbach wrote: holds speed good enough for me and my wife, that's for sure. i have wakeboard pro with a paddlewheel. i don't ever recall PP being anywhere outside of a set point of more than a 1/3 of a mph after it hits it, at any speed. even that is rare. it's that good.

That is really good info, Josh. Was that skiing, wakeboarding or for both? It sounds like PP will do as well or better with GPS, because their website makes it sound like they are moving to GPS speed control (they say, "(The paddle wheel is no longer required)").

Thanks for the input, guys.

I agree, Chris, I'm sure that was one thing that Joel was getting at, and I'm sure that's right. But I think it can still be quantified somewhat. Does GPS- or paddlewheel-based PP vary +/- 15 mph when pulling an aggressive wakeboarder? Of course not. Does it hold to +/- 0.1 mph? Of course not. So it should be possible to quantify it, something like... "With a 220 lb strong wakeboarder cutting aggressively, on smooth water the paddlewheel PP would generally hold within +/- 1.2 mph" -- or something like that.

Does that make sense, or am I asking something that isn't reasonable... because that's kind of how I planned to test our project, when I someday get it installed.

M3Fan wrote: Also I guess I just don't really understand the whole "cheap" cruise control thing.

Billy boat doc made his own using an inexpensive automotive unit. Since Billy's name came up in the first post, I feel this is what was done.

bkhallpass wrote: ...I value PP far more for pulling a wakeboarder. ... If you lose even a half mile an hour at wake speeds, it can be the difference of planing, or not; of a crisp wake, or a mushed out wake; of dropping the surf handle, or not.

Brian, that matches with what Gary wrote in my other thread and what I've read elsewhere. That's why I'm looking to slave to GPS rather than RPM.

TX Foilhead wrote: I'm going to take a guess at Billy wasn't all that intrested in an exact speed, just a steady cruise.

I think that's right, Don, based on the short phone discussion he and I had.

TX Foilhead wrote: My stargazer holds within ,25 mph in each direction when it's set up properly from 20 to 30 mph. It will hold within 50 RPM's. The better the person on the end of the rope the less you should feel because they properly load the line, the pull is harder, but much more suttle and requires a different technique than the idiot who cranks a hard turn outside and proceeds to loose line tension all the way to the wake.

Wow, 1/4 mph is amazing! What mode are you running in... RPM, paddlewheel or GPS? I agree on rider skill being a large factor--gives me something to blame my son with if he doesn't like the speed control, lol.

bkhallpass wrote: A really strong wakeboarde can slow my super Air down a couple miles an hour. It's not the instant slowing that matters, it is how fast does the system correct. If it corrects quickly, I never lose plane or wakeshape.

TX Foilhead wrote: Your problem will be you have no way to change the pulls for different riders so you're basically holding speed in RPM mode and a car isn't real aggressive with the throttle until you've lost a few mph.

I agree about the speed of the correction. I have a few tricks to try to improve the responsiveness of the control circuit.

Don, what do you mean by "change the pulls for different riders"? I'll be running in GPS mode.


Thanks for all the replies.

Steve

Not a CC but PP has been the single best upgrade to my boat and even though it's expensive for what the components must cost them, I feel it's worth it. I have electronics and software skills good enough I could probably come up with something that works but for a one off project it's not worth the time given I have too many projects as it is. To the guy who said if you don't make your own speed control you may as well hire out stringers, engine rebuilds, general maintenance, lawncare, etc... I prefer to do everything myself but at some point you realize you just don't have enough time to get it all done and to some that means buying PP or RideSteady out of the box ready to go, or to others it may mean hiring out stringers to make the job smaller or hiring a lawn service so you have time to do stringers yourself and get a net savings. Different strokes for different folks.

Anyhow, boat is a Supra Saltare (23' 3500 lbs dry) with PCM 454 and paddlewheel PP. I haven't watched it like a hawk but at 22 MPH it generally holds within .5 MPH +/- with an average rider and .75 +/- with a aggressive rider. I haven't messed with the settings to get that smaller as it corrects very quickly and while riding I can't tell there is any fluctuation in speed. For me, it has been worth every penny.

Your Model & Engine: 1993 Ski Nautique 240HP 1:1 Trans
Stargazer PP with No Paddlewheel

RPM Hold Mode

Cruising (indicate speed): 30 No Fluctuation
Wakeboard (17-23mph): 19MPH 1 MPH Fluctuation at Most
Slalom (25mph+): 32 1 MPH Fluctuation at Most



Paddle Wheel Speed Hold Mode

Cruising (indicate speed): NA
Wakeboard (17-23mph): NA
Slalom (25mph+): NA



GPS Speed Hold Mode

Cruising (indicate speed): 30 MPH No Fluctuation
Wakeboard (17-23mph): 19MPH 1 MPH Fluctuation at Most
Slalom (25mph+): 32 1 MPH Fluctuation at Most


The previous owner of my boat installed PP Stargazer 3 Event, which is great. I recently did a system reset, and started it back up as a Wakeboard Edition to take away some options and make it a little simpler. I don't have a course available to me unfortunately, nor a jump.

The PP Stargazer is great, but honestly, if I was spending my own money on it, I'd probably just get the PP RPM Cruise for $675.

I spend a lot of time in RPM mode anyway, especially since sometimes I'm running kinda close to a treeline (to get sheltered water), which occasionally messes up the GPS signal.

On a direct drive boat, there is a "direct" corraltion between RPM and speed, Edit: at almost all speeds. I could see how a V or Stern Drive might fall off/on plane at a given RPM, so the GPS could be more important in that case.

Bri892001 wrote: Your Model & Engine: 1993 Ski Nautique 240HP 1:1 Stargazer PP with No Paddlewheel ...

Thanks, Brian, that's exactly the kind of info I was looking for.

M3Fan wrote: ...if PP has not sensed a gate magnet (or GPS coordinate with the updated version) it's not in the course so it will hold speed via GPS or RPM based on Stargazer/no Stargazer until it senses an entrance gate. ZO knows it's approaching the gate via GPS coordinates. Once in the course the systems use GPS to measure distance between ball segments to know how they are doing and adjust appropriately. Traditional PP uses magnets for segment timing, either all 6 balls or gates and 3 ball depending on the setup. ZO pulls exact times to the hundreth of a second in all conditions with all skiers and offers 18 different choices for pull feel- settings A1 through C3 and +/no + for all 9 modes which alters pre-gate speed. Truly, truly incredible system. I ski ZO in the course almost every weekday morning and drive well over 600 passes through the course per year with ZO, it is an amazing system.

Thanks, Joel, I didn't know the timing functions went to that level. That is truly impressive. I can see why someone skiing at your level would want that kind of capability in the speed control. Yes, we won't need that level of functionality. My daughter is a novice slalom skier and my son a medium-level wakeboarder.

Steve

You're welcome. Also, mine is carbureted. That might make a difference too. I'd imagine an EFI engine might be able to react a little more quickly/precisely, at least in the range where a carb'd motor would be into the secondaries.

TX Foilhead wrote: As for the different pull I spend most of time time with foils...

Don, what are the foils about? I'm not familiar with those. Not sure I've ever seen anyone on one at the lakes and rivers we go to.

TX Foilhead wrote: ...RPM mode ...soft and forgiving. MPH ...feels a little hotter ...most people I ride with find it easiest to run RPM mode, but the best people usually want MPH so it's set for a pretty aggressive pull as soon as the speed begins to slow.

We'll see if this is an option I might have--to be able to switch modes--but I don't think so. It would be easy enough to install the magnets and pickup and use a switch to change modes, but all the sensitivities on this unit are set via dip switches. So I probably wouldn't be able to change on the fly. For our use, I'm going to start with GPS and see how it works out, and riders will have to choose that or the really soft option (average drivers!). I'm waiting for some final info from manufacturers and then I'll be ordering the last components and my son and I can get on with it!

Thanks.

Steve

Way back, in the late nineties, one of the club members was working on a PP clone. I have one of those clones around here somewhere. Mine just used RPM and held speed based upon that. He was working on an algorithm for slalom out in one of the private lakes adjacent to I-5.

Apparently, PP gave him a used unit from one of the championship tournaments and he stopped working on it.

My thoughts are you definitely would want one with an algorithm for slalom. Holding RPM in the course results in a stiff feel for lack of a better word. The PP's use sensors for the magnets for the gate and buoys. It tries to mimic a pro driver from what I've been told. It does feel much better in the course than holding RPM.