The only toy that gets better as it gets less efficient...

[tdc_worm]

I had the opportunity to spend the afternoon in G23 the other day, much of it behind the wheel. I didnt confirm the engine or prop (guessing the 450 and stock prop), but cruising anything over 24mph was bouncing off of the 4k rpm mark with 4 men and 4 women aboard. That got me to thinking that my 2007 236 has a max sustained operating RPM of 4k (according to the manual) and that usually puts us around 28-29 mph.

With boats getting bigger and every effort being thrown at them to be less efficient (i.e. more displacement = bigger wake), that has to dramatically reduce engine service life. The non supercharged engines used to be fine with the 1.48:1 gear reduction, now they are 2.0:1 in the G Series...thats a greater than 25% difference! I wonder if we are going to see a dramatic reduction in rebuild intervals because of this. Sure would be a bummer if the big elephant in the room that nobody wanted to talk about was that your $120k boat would need a rebuild in 3-4 years if you were a heavy user.... The other elephant in the room is resale...if that does become the case and reports do surface, used buyers will become savvy to it....

Just for comparison on how much harder we are having to work these engines:

2007 236 with a 390hp ZR6 6.0L, 1.48:1 gear reduction, 14.25 pitch prop
2014 G23, with a 409hp 6.0L, 2,0:1 gear reduction, 12" pitch prop (holy RPMs!!!!)
2014 G23, with a 550hp s/c 6.0L, 1.48:1 gear reduction, 14.25" pitch prop

With all other variables being the same, the 550 engine is still going to be turning more RPMs than the ZR6 because it is pushing a lot more boat...

[NautiqueJeff]

Couple number corrections for you...

The 2:1 boats have 17" props.
The 550 is a supercharged 6.2L engine.

[tdc_worm]

Couple number corrections for you...

The 2:1 boats have 17" props.
The 550 is a supercharged 6.2L engine.

point noted on the 550. about the props:

the boys whitelake must be off. nautique parts says ACME part number 2313

http://www.nautiqueparts.com/propell...nautiques.aspx

ACME says 2313 is 15x12.

http://www.acmemarine.com/prop-list_ski-boat.php

[NautiqueJeff]

Nope. 2561 is correct. 17x17 it is.

http://www.nautiqueparts.com/propell...utiques-1.aspx

The 2313 is for the NON-2:1 409/450 G-series boats.

[tdc_worm]

alright...sorted that out...i think. the 2313 is for the 1.48 equipped 2013s w the 409/450. in 2014 the 409/450 jumped to a 2.0:1 drive with the 2561 (which has a retail of $1299!, more than twice the other props listed).

To not digress, the 2014 I was on still was running considerably higher RPMs than I am used to out of my 236...the higher sustained RPMs under load have to result in more wear. how much, I dont know. I guess time will tell....

[aZ`]

Let's also not forget the way we are using these boats now. Surfing puts the motor under a lot of load. I personally would think a motor used for cruising/wakeboarding for 600hrs may well have less wear than a motor used for surfing does after 400-500hrs.

[nyryan2001]

couple thoughts.

The boats are doing a lot more as the become more inefficient. apples and oranges to compared to how they were used a few years ago. G owners are regularly using 3-5000lbs of ballast.

But to say surfing is harder than other sports, i donno. A slammed wakeboat at launch revs to 5000+ rpms as it runs up to 23-24mph, then settles at 3500-4000rpms.....this rivals any use we see in surfing, which rarely exceeds 3500rpm. I rev to 3500 and settle to 3000-3400ish.

Wanna talk barefooting at 5000-5400rpms for long extended periods? thats not extreme use? come on guys.

also, tdc's logic about the trannys and inefficiency is flawed. whats happening is a fundamental shift from 5-10yrs ago where the majority of inboard owners needed 40mph+ for barefoot and a strong comfy 35mph+ for slollam (ie 14"+ pitch props). most of that is gone, folks have a fraction of the interest for those activies as compared to a decade ago. The majority of wakeboat owners have no need to exceed 30 mph, so the trannys and props reflect that, and the demand for increased capability to carry 3k+ loads of ballast brings everything down slower. Honestly, I cant remember the last time I went over 27mph in my boat?

the most efficient props (for heavy wakeboats) are where pitch = diameter, where dia is as big as you can get (to maintain hull clerance) and still be tranny geared to be able to swing up to 5400-5500rpms at WOT. That larger dia is the fundamental key to reducing prop slip and becoming more efficient, more bite on the water when carrying heavy 3-5k loads.

Yes they are using more fuel to do these activities, and yep its crazy at 15+gph slammed. But then the title of this thread should be the fundamental shift in wake interests and how folks use their boats.... and how the manf's are responding in delivering these new boats with new capabilities.

[aZ`]

The only toy that gets better as it gets less efficient...

But to say surfing is harder than other sports, i donno. A slammed wakeboat at launch revs to 5000+ rpms as it runs up to 23-24mph, then settles at 3500-4000rpms.....this rivals any use we see in surfing, which rarely exceeds 3500rpm. I rev to 3500 and settle to 3000-3400ish.
.

Whilst this maybe true. Rpm only tells half the story. Wakeboarding is performed with the boat on a plane and may well do 3500rpm but also might only require 20-30% throttle to maintain speed. Surfing is done while the boat is ploughing and never gets up on a plane and may be performed at 3000rpm but could require upto 60-80% throttle to maintain speed. This is why fuel usage figures are always the worst for surfing. If it's using more fuel I think it's fair to say it's under more load. Sure it may stress different parts of the engine to what extended high rpm does, but ignoring it won't make it go away.

[nyryan2001]

az, this is where we part ways, your claims are :

60-80% throttle at 3000 rpms to maintain 11mph? only if you have the wrong prop on there. I can spin 5000rpms at 11mph if I were to over load the boat. this makes no sense whatsoever.

fuel figures always worst for surfing? where are you getting this from? Perhaps you need to go read what Iron reports with his G at 23mph when slammed. 18+gph at times. He is taking wake surfing loads up to 23mph. fuel usage is a function of rpms. there is no such thing as an easy 4000rpms on a one gear V8 inboard. boats guzzle fuel as you go north of 3500rpms, nearly double gph of what you see at 2700rpms, it not linear.

and trying to figure out how you think the speed of the water going by outside the boat has much to do with anything.

[aZ`]

Happy to agree to disagree on this one. Carry on

[tdc_worm]

couple thoughts.

The boats are doing a lot more as the become more inefficient. apples and oranges to compared to how they were used a few years ago. G owners are regularly using 3-5000lbs of ballast.

Agreed on that. People used to have to "work" (i.e. fill sacks and/or plumb extra ballast) to slam their 4000 lb boat. Now, the G's have given the average wally the ability to dump 2800lbs on top of their 5000lb boat. So its not just people in the know about about extra ballast or those that are willing to work for it...EVERY G engine is getting worked harder (because the weight and ballast is built in) compared to select previous users that preceeded it.

But to say surfing is harder than other sports, i donno. A slammed wakeboat at launch revs to 5000+ rpms as it runs up to 23-24mph, then settles at 3500-4000rpms.....this rivals any use we see in surfing, which rarely exceeds 3500rpm. I rev to 3500 and settle to 3000-3400ish.

Wanna talk barefooting at 5000-5400rpms for long extended periods? thats not extreme use? come on guys.

The difference is that slalom and barefoot hulls are designed to get on top of the water. When they do, the lessen their coefficient of friction...all boats do they faster they go, which is why their wakes get smaller. And to say that the engine feels less "load" is also incorrect. Try putting your truck in neutral, unloaded, and pushing it by hand across flat ground. Now do the same thing with your trailer/boat attached. Do you struggle more? Is there more stress on your joints? Do you use more energy? Which scenario would be easier to injure yourself? Same thing happens to the engine under load.

also, tdc's logic about the trannys and inefficiency is flawed. whats happening is a fundamental shift from 5-10yrs ago where the majority of inboard owners needed 40mph+ for barefoot and a strong comfy 35mph+ for slollam (ie 14"+ pitch props). most of that is gone, folks have a fraction of the interest for those activies as compared to a decade ago. The majority of wakeboat owners have no need to exceed 30 mph, so the trannys and props reflect that, and the demand for increased capability to carry 3k+ loads of ballast brings everything down slower. Honestly, I cant remember the last time I went over 27mph in my boat?

sure, you can alter the final drive ratios by moving transmission ratios around. but at the end of the day you have to be operating at certain RPMs to tap into the engines power. to do that you inversely change the prop pitch. same thing as trucks with big tires...the bigger tire (i.e. higher pitch prop) is countered by running lower gear ratios in the rear end.which are numerically higher (i.e dropping from a 1.48:1 ratio to a 2.0:1 ratio tranny). As for pitch, for those that don't understand it, pitch is the forward movement in inches that a prop would move itself after removing any slip or other inefficiencies. or course diameter and cup will all serve to effect the "purchase" on the water to reduce slip. to much purchase and a prop will start to cross walk the boat...which is why Nautique uses tuneable rudders.

the most efficient props (for heavy wakeboats) are where pitch = diameter, where dia is as big as you can get (to maintain hull clerance) and still be tranny geared to be able to swing up to 5400-5500rpms at WOT. That larger dia is the fundamental key to reducing prop slip and becoming more efficient, more bite on the water when carrying heavy 3-5k loads.

I won't question you there as I don't know, but would like to learn. Have any references? Also, if this is true, then why did Nautique not elect to make the 550 s/c option more efficient?

This is all good discussion. At the end of the day its all about RPMs and being able to move the torque curve down. The only way to do that without forced induction is to increase the size of the rotating assembly. I like MCs choice to use a 7.4L 454 in the XStar. The only other way to do that is to turbo or s/c it....

[surroundsound64]

I'm with Ryan. My boat sees WAY fewer RPMs surfing than slalom skiing or boarding. I've thought about installing a MAP gauge to really be able to tell what kind of load the engine feels, but don't think that is really necessary because we are dealing with rigid drive lines and fixed pitch propellers.

[Dave Rittiman]

I wonder if they would ever be able to create some kind of 2 speed auto trans and put a overdrive in it ?

[DanielC]

I believe some are over thinking the ways for figuring out the load on the engine.
I look at it this way. How much fuel is the boat engine using per hour?
More fuel, more load. It really is that simple.

[tdc_worm]

I believe some are over thinking the ways for figuring out the load on the engine.
I look at it this way. How much fuel is the boat engine using per hour?
More fuel, more load. It really is that simple.

I concur. Its also important to realize that barefooters and slalom skiers are pushing much lighter boats designed to stay on top of the water. There is undoubtedly less load placed on their engine. Thing of it like driving a lighter car with no headwind. For the G series, it would be like driving a heavier car in to a head wind. Pushing the head wind has similar fluid dynamics to plowing more water. With the same engine, one is certainly going to have more load than the other.