Are more powerful slalom boats easier or harder to ski behind?

[us_tdl]

Seems like people have a lot of different ideas on this subject and I thought it would be interesting to get some opinions. From my limited experience, it seems like the boats with more power tend to fluctuate less in speed meaning the skier feels smaller speed corrections. I perceive this as good/easier to ski behind. Other people seem to think that powerful boats have the opposite effect. What is the truth about more powerful slalom boats?

[chris_logan]

This would make for a good poll...

[ral]

@us_tdl‌, less fluctuation in speed makes skiing far more difficult. Remember ZO version N?

[us_tdl]

@ral Sorry I'm not familiar with all of the ZO updates. I was basing my opinion off of skiing behind multiple 5.7L boats (namely the malibu TXI and mastercraft prostar) and comparing them to a centurion carbon pro with a 6.0L. The centurion actually seemed to ski softer even though it had more power. Was this because of some other factor?

[Jody_Seal]

In my limited experience (hic) bad calibration or programming can make a week boat ski hard.

 

Something that I learned a long time ago when working with the Hobbs Speed control system: When a given boat has a given gear ratio and a given propeller, the engine utilizes X Horsepower to pull a skier of a given weight, line length and speed whether the engine is capable of a total torque/HP of 300 or 600 it will still only utilize X HP for the given skier!

 

Now again in my limited experience gearing and propeller have a bigger impact on how well (or Not) a ski boat will perform with higher HP engines.

 

More to come later.

[ral]

For the MC. if it is not the 2014, for sure it is the boat...

 

The intent of the original ZO software (version N) was to keep constant speed and it was hated...

 

Constant speed make things more difficult. Skiers do not feel small corrections, skiers feel that the boat is pulling where it should not be.

[us_tdl]

yeah the MC was a 2013. I figured some people on BOS understood the topic more thoroughly.

[Wish]

Well, just skied behind Tom Asher's at ActiveSkiing and he said it was the strongest jump boat anywhere. Matched my average. June asked if I noticed any difference when i had finished. I really didn't. It was then that I found out it was a much higher HP boat. But, I ski behind all kinds of different set ups. Soooooo... I just ski.

[Horton]

I know that with most boats I run B

 

if a boat seems challenging I move my setting to C

 

the logic is I don't wanna pull the boat down this much before it rebounds

 

Fyi A just scares the crap out of me

[DanE]

I´m with @Jody_Seal on this one.

As long as the boat is not under-powered the main factors should only be prop and gear ratio coupled with speed control setup that produces the feel of the pull (for any given hull I might add).

I like the feel of the pull behind the CC 200 and I really think it comes down to the fact this boat is bigger/heavier than it´s predecessors coupled with superior tracking.

All of that makes the boat keep the momentum going better when the skier applies the load, and therefore fluctuates less in speed with less amount of catching up to speed.

[BRY]

I like the 6.0L boats better, they seem less "peaky" and the pull is smoother. Don't think I would say softer (definitely not harder), but smoother and solid. Think its due to typically lower RPM and "bigger" prop, harder to pull them off so they don't hammer to get back on.

[SkiJay]

I normally ski behind a 5.7L 200. When I ski behind two different neighbours' 6.0L 200s, I find the prop wash roost to be bigger and more firm than that of the 5.7 at 28 off. At - 32 and shorter, if there's a difference in the wakes or the pull, I haven't noticed.

[MAD11]

I can say one thing. I am having to ski behind a 196 5.7L Nautique right now at 6000' elevation and all I do is pull. I can't get anywhere, get no space and just chase the thing and it frustrates the hell out of me. I don't think ZO works well with that little horsepower. (It wasn't designed for it either) I found a calculator on the internet and it tells me to factor the horsepower at .77. So I guess that means the old 343HP is really only giving about 264 hp. I can't wait to get back home to my 5.7 Malibu at sea level or a 200 with a 6L. (I always like the 200 6L better than the 5.7)

[Gloersen]

Regarding the SN 200 – the 6.0 has always felt like a smoother, less harsh pull, actually better buoy scores. Though I do select a lower clipping value, .08 vs 0.1, (2 vs 3), on the 6.0, always Kd gains of.7/.3 ©.

 

Have noticed something similar in PP era, GT-40 vs Excal 330/343, the 330/343's always felt smoother.

 

Fwiw… doesn’t really matter, will ski behind anything that yields a 16.95…

 

[skialex]

Lately I mostly ski behind smaller engine 196s with many hours and poor maintenance. They straggle to pull me out of the water (178lb) and I have this feeling that when I pull the boat's ZO response is harder making it more difficult to run the course. I'm not sure if it is my skiing or the underpowered boat that make me straggle through the course (probably both) but I tend to believe that a more powerful engine would deliver a smoother more consisted pull through the course.

[Razorskier1]

The 6L 200 pulls very nice. All the other boats I've skied behind are 5.7L and I think they are fine too. The 6L 200 probably feels the smoothest.

[Jordan]

@skialex, I am amazed that any direct drive would struggle to pull 178 pounds out of the water.

 

I am 200lbs and I have 1993 MC with an LT-1 (no powerslot) and it has way more than needed out of the hole...I also ski mostly behind a 197 with the base engine, it also has more than enough to pop me up.

 

 

[ral]

I do not notice much difference between the 5.7 and 6.0 Nautique 200.

 

Between the 5.7 196 and the 6.0 196 I do notice. I feel the response is harsher with the 6.0, and the wake is harder with the stock propeller.

 

Not trying to be disrespectful to anyone, but we really dislike the slalom pull and wake of the 2012 and 2013 MC Prostar with the 6.0 engine. For Nationals, and because of "popular vote", slalom will be pulled by a 2014 MC Prostar, even though there is only one boat and no backup. Jump and tricks will be done behind the 2013's.

[Chris Rossi]

Stronger boats do not need to work as hard to hold speed and thus to me feel like they give a softer pull. This is very evident here in Utah where the course is at 5000+ feet. Even in FL I would opt for a 6L Malibu or Natique if offered over 5.7.

[skialex]

@jordan I exaggerate by saying struggle to pop me up but at that moment is when i know that the engine can not deliver the power it should during the pass. I'm not 100% sure about this but I would like somebody to verify that an underpowered boat could cause a not so successful ski set even if the time is 16.95 or is it just me?

[Jordan]

An underpowered boat is going to have to surge more than a more powerful boat to hit your 16.95

 

I hesitate to bring this up, but everyone's focus on peak horsepower is a little off base. What matters is the torque produced, or you could look at the horsepower at the specific rpms required for your speed.

 

If you feel that your boat is doing this, the answer could be as simple as getting a lower pitched prop. This will do two things, it will give you more hole shot for your deep water starts, and it will have the engine operating at higher rpm's for a given speed. This will mean that the engine is operating further up the torque curve, putting out more horsepower at your skiing speed.

 

 

[skierjp]

The boats have not been decided on for Nationals.

[skierjp]

 

The random boat draw will be posted July 1st

[ral]

@skierjp, if you are posting in response to my comment, you got the wrong Nationals...

[skierjp]

Whoops

[Ghibli]

@Mad11 Does ZO ever "bark" at you demanding more power even though no more is available? Most likely pulling a heavy line skier. My understanding, which can be misguided, is that if ZO does not have the torque to perform as programmed(maintain g forces when required) it will let you know. At sea level that usually means the throttle lever was not moved forward enough.

 

My guess as to why more powerful boats feel smoother is because they are operating in higher gears(more pitch, diameter) and really are....smoother. Profound i know. Much like an overdrive compared to a lower gear. Try to moderate speed in your car in first gear compared to fourth at say around 35 mph. Increasing pitch smooths out the pull and slows response time to target g force as well, which most, not all, of us find friendly. But if you add too much pitch, ZO might bark and you may overstress/heat your engine.

[DanE]

@Ghibli Probably the truth!;-)

[Bruce_Butterfield]

Setting aside the Hp vs torque distinction and ignoring prop slipage, a "more powerful" engine will get pulled down less (loose less rpm) when the skier pulls, so ZO will react less. It is the reaction of ZO (adding throttle and accelerating the boat) that makes the pull feel strong or too harsh.

 

For example, if you have an old 240 Hp boat and a strong skier pulls it down, ZO will essentially give it full throttle to try to get back to speed. That will feel strong as hell to the skier, but still get a 16.95. Compare that to a 400Hp boat with the same skier's pull and the engine will loose much less rpm and ZO will barely have to nudge the throttle to get back to speed. That will feel much easier on the skier's end of the rope.

 

The easiest slalom pull will be from the proverbial tug boat - a high torque engine turning a big prop. When the strongest skier pulls, the speed and rpm will barely change. ZO will think there is a 6 year old girl on the other end of the rope and will barely react. This is the only way to get even close to the "constant" speed that the speed control proponents harp on.

 

Jumpers, on the other hand, want lots of acceleration - they want a monster engine AND ZO giving all the throttle it can. They would absolutely hate the constant speed slalom tug boat.

[Ghibli]

@Bruce_Butterfield This is just the understanding I have gathered and, again, could be completely off base. There are many articles about ZO with disclaimers that the author is just sharing their theory. ZO's website does not delve into the functionality, so a lot of misunderstanding is out there. If someone has a definitive source and, not hearsay, please feel free to refute. I've come to the realization that too many "sources" for ZO information were not even aware that the system has accelerometers and still look at the system through their PerfectPass lens. ZO's use of accelerometers is confirmed on the ZO website.

 

I would agree with some of your post if you substitute PerfectPass for all your ZO references. While ZO has a rpm mode, ZO in tournament mode does not care about RPM. Accelerometers, combined with gps determined speed, control engine response. This is why ZO is able to give "perfect" pulls without knowing anything about boat load, skier weight, wind or current. The system "senses"(through the use of accelerometers) what the boat is actually doing as opposed to an inference from rpm change. What appears to be clear from comparing different sources of information is that the ZO number setting controls maximum allowable acceleration to return the boat to speed after a load has caused a deceleration and the letter determines the path to that maximum acceleration and the path back down to zero accelleration. In this spirit, the system does not really care what engine it is controlling, as long there is enough excess torque available to accomplish the software's objectives. However, we are not using ideal power sources, so there will be differences between similar and dissimilar power plants, which I touched on in my previous post.

 

Boat weight and stability will also have more than a secondary impact on how the pull feels. And might as well throw driver technique in there to be thorough.

[MAD11]

@ghibli It will tone the entire way down the course with me, but I am known to pull a little bit at times. Believe it or not, it will even do it at that elevation with my daughter when she gets to 35off. It's obviously the elevation, but just makes everything harder and you never get into a rhythm. I have just started running back to backs at 32 off behind it and will wait til I get home in a few to shorten up.

 

@bruce_butterfield Right as usual. Last season while waiting for a new promo boat to come in @Tfin and I had to ski behind Jimmy's Siemers MC jump boat everyday for about 2 months. The thing is crazy strong and all we did was bitch about it for the first 2 days. After getting accustomed to it we started running some of the easiest and earliest passes ever. Hope your doing well and not freezing back there.

[Bruce_Butterfield]

@ghibli yes you are right - ZO doesn't care about rpm. I was trying to keep the explanation simple in an "everything else being equal" scenario so rpm and speed would be directly proportional.

 

So if you assume no prop slippage, any drop in speed will have a corresponding drop in rpm - the same way your car engine will loose rpm as you slow down going up a hill. Zo is really responding to the change in speed, which with a "weaker" engine will change more than a "strong" engine.

 

You are also right on the disclaimer. This is my understanding and theory based on experience. I have no more inside knowledge about how ZO really works than anyone else on this board.

 

Mad, this has been about the coldest winter I've seen in TX in 30 years. At least you're on the right end of the planet!

[Jody_Seal]

Bottom designs, Hook, Rocker and other bottom attachments in conjunction with engine/trans configurations along with propeller (Still a Black Art) dictate how the boat will respond to a given skier. Add in crew/equipment weight and Speed control a boat can feel to a skier good or bad depending on the set up.

An engine that produces higher torque numbers in the 3500-4000 RPM range will help overcome the inefficient wetted surface's and heavier hulls that seem to make up today's tournament boats. However Their is a delicate balance in today's boats as a give in the pull feel seems to be preferred, no one wants to ski on a steel cable Feel.

It seems that the Higher HP engines are starting to become preferred and have better overall performance for a wider range of skiers. Finding the perfect powerplant for a given hull design is not alway's easy yet the LS platform seems to be gaining in popularity as it is able to overcome the heavier inefficient wake diffusing ski bottom configurations.

 

Reduction 6 liters I prefer C-1 on the ZO. 1:1 boats B-2, 5.7 Reduction boats ???? don't see many, 6 liter 1:1 well their is that steel cable feel!

 

 

 

 

 

[6balls]

As a chronic over-puller using strength in order to some extent to make up for technical deficiency...the Jody Seal 409 or 450 Nautique is the softer pull as compared to the MC 197. Skied 12 rounds in each of 2 years behind each boat alternating over a tourney weekend and I just felt slung by the 197 whereas Jody's Nautique was all buttery producing my two best ever tourney scores. I've NEVER made up time at 38 after a crap-o one ball, but behind Jody's did so only to botch a 5 ball after being back in the game. The other round behind Jody's boat smoked 38 and had a "real chance" start at 39 only to over-turn the 3.

For other skiers including my historically over-pulling brother who is more technical than me...he felt no difference.

Could have been in my head...but wake was not an issue...seemed like the 197 was giving me the business as compared to Jody's 200's...ran my 35's but 38 felt like I had no chance. Disclaimer: I train on PP.

Jody...keep bringing a boat to skiwatch fall double...I will keep cooking ribs at TJ's.