G23 Prop Fell Off .....

[charlesml3]

Are you saying there are cases where the shaft has failed but the boat was NOT used to surf? This would be very different than all of the reported cases thus far.

Yes, absolutely. One of my friends is a Wakeboard instructor. It's a G21 and never used for surfing and has had 2 shaft failures.

-Charles

[greggmck]

It happens randomly under different driving conditions and at any number of hours. There is no rhyme or reason. It's happned on brand new boats with 2 hours, and with pros boats with over 700.
For instance, I was just out cruising for probably 3 hours - a combination of idling and cruising at 25mph with no ballast. When I went to pull into a dock and tapped it into reverse, the shaft broke.

It's a bummer, but not worth the anxiety of thinking it may happen. Just use the boat and enjoy the short summer!

The circumstances occurring at the time of the failure are not what cause the shaft to fatigue. It is my understanding (after speaking with engineers working on this) that the primary cause is an asymetric load on the shaft that occurs after extensive surfing. The force focal point is the end of the keyway closest to the strut and this is where the failure occurs. Are you saying there are cases where the shaft has failed but the boat was NOT used to surf? This would be very different than all of the reported cases thus far.

[wakerider107]

I wakeboard almost exclusively. But do like to surf once or twice a year... Now I am super apprehensive about going surfing...Since people seem to say it happens more when surfing or when people surf more often....

It happens randomly under different driving conditions and at any number of hours. There is no rhyme or reason. It's happned on brand new boats with 2 hours, and with pros boats with over 700.
For instance, I was just out cruising for probably 3 hours - a combination of idling and cruising at 25mph with no ballast. When I went to pull into a dock and tapped it into reverse, the shaft broke.

It's a bummer, but not worth the anxiety of thinking it may happen. Just use the boat and enjoy the short summer!

[NautiqueJeff]

[scottb7]

I wakeboard almost exclusively. But do like to surf once or twice a year... Now I am super apprehensive about going surfing...Since people seem to say it happens more when surfing or when people surf more often....

[dlowry81]

Skipdawg pointed out the difference in a very politically correct and nice way. I would've called your dealer an idiot and throat punched him for even insinuating that a complete random mechanical on my boat with no warning or way to prevent it from my end that would leave my family stranded in a lake is even close to a Tesla running out of juice.

[Skipdawg316]

The Tesla analogy is sightly different than this.

You can see your battery range in miles at any given moment. If you use the map/directions, the car won’t go out of range without letting you know you will have a problem to get to your destination.

So, if your battery does die, it wasn’t for lack of warning. Yes, range anxiety is a perception, potentially impacting buyers, but it’s pretty quick to get over when you see how it actually works.

Here, a shaft breaking is a complete surprise, with no apparent way to prevent and does not have a clear pattern as to why, which to me is much more nerve racking and far more difficult a perception to overcome given all of this.

I have a 2017 G23 with 114 hours on it and lately I’ve been wondering when we go out, if today is the day.


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[RDT-G23]

I’ve managed to calm down following the issues I’ve had with my G in the first year. I really like the boat. If my prop shaft were to break, well, it just wouldn’t be good. Ironically, last spring when I was talking to my dealer about this issue, he joked about the anxiety Tesla owners can have without the ability to re-charge to my own concerns of this happening, and my being stranded,,,

[GMLIII]

i'd venture to say that nautique would not warranty a shaft that came in with a modified keyway like that. anything to point the blame elsewhere and avoid the warranty claim.

I like Infinity's method. I'm trying his approach now on my 2017 G23

[jtryon]

If I owned one of the affected models I would use a dremel tool and gently radius the sharp edge of the keyway. After the dremel work I'd polish with medium and then fine sandpaper. Make sure the whole thing has a smooth radius and not a sharp edge.

i'd venture to say that nautique would not warranty a shaft that came in with a modified keyway like that. anything to point the blame elsewhere and avoid the warranty claim.

[Infinity]

Since they seem to have a "better" shaft now......I think I would weight the heck out of it and hammer down to get the break over with, that way I could get the new shaft installed and be done with it. Sounds like there is no preventative replacements, rather they want you to first get stranded, waste an afternoon and $500 on tow bill (if your lucky and not too far away from your dock), then you are allowed to get it replaced after spending +/- week without boat. Guess it remain to be seen if these new shafts will stand the test of time tho

[larryb]

Wow, what an amazing thread. Owning an older Nautique I haven't been on the forum in a few years.

I have an idea on the failure mechanism and something owners can do to mitigate the problem. Cracks such as these often start at a "stress riser" or a sharp edge in the shape. the sharp edge of the keyway is a stress riser. If the stress riser can be reduced the the likelihood of a fail can be reduced. If I owned one of the affected models I would use a dremel tool and gently radius the sharp edge of the keyway. After the dremel work I'd polish with medium and then fine sandpaper. Make sure the whole thing has a smooth radius and not a sharp edge.

Another thing to verify is that the torque on the prop nut is at spec.

https://en.wikipedia.org/wiki/Stress_concentration

Larry

[cmerritt]

Cmerritt,
Do you run extra ballast? It does seem there are fewer failures with just stock ballast. I am going to venture more than stock, since you propped it down (are there high elevation lakes around there?).

I was hoping to believe in the theory that you either get a bad prop shaft or not, and that once you get to 100 hours, failure is less likely.

I notice that it broke inside the prop hub, like most do, and I wonder if the taper of the shaft and hub do not match, or that by not putting the appropriate torque on the nut, it might contribute. (either too much or too little torque).

Hey Tallredrider,

When I bought the boat I purchased extra bags for the front a rear with a pulling prop. I did this because every other boat we've ever had needed extra bags. We used the extra weight maybe 4 times.

I surf factory ballast full and my wife surfs with the ballast empty on her skim board. When the prop shaft broke we had 50 percent ballast and a friend behind the boat. We typically drop in the river or the lake get a few sets in and pull right back out so we never really need cruising speed across the lake. Since we had been exploring some other lakes recently I almost changed back to the original 17x17 a few weeks ago and just ran short on time so it didn't happen.

Most of our wakeboarding is just factory ballast full for me and about 20 percent for my wife. I realized this boat has plenty of wake for my skill level without any extra weight.

Regards,

Cmerritt

[dlowry81]

I can't help but think of how quick this would kill a brand and the liability associated if this were related to an offshore boat manufacturer. I know everyone on here and the other forums defends their brand of choice to death with phrases like "there is a lot of technology on these boats now a days" and "you can't expect perfection that is what warranties are for", but honestly the failure rate of all the big 3 and the number of people I see on the internet being towed in on 1-2 yr old $100k+ boats is astonishing. What's more astonishing the lack of ownership to the problem from Nautique and from Malibu on their screens going bad.

[Bevostein]

I find it amazing how similar all the breaks look and in the consistency of location. I am not an engineer, metallurgist, mechanic or anything remotely qualified but it seems awfully obvious and suspicious that these breaks all occur at the keyway. It has to have something to do with the keyway.