G23 Prop Fell Off .....

[Quailhii]

2018 G23 - Prop Sheared Off

Proud new owner of a 2018 G23, purchase one week ago - 6.30.18 (Reside in Seattle / Lake Washington)
Yesterday the prop sheared off, and wow was I shocked. We were out with friends (7 on-board) doing a lazy cruise Lake Union, then headed for Kirkland, ramped up to 30mph crossing the lake. As we approached the marina, I started to back off, there was a slight shimmy or vibration at about 10mph and then I felt or heard a clunk, a slight rev of the engine and then no propulsion. I had no clue what occurred, but when I engaged to move forward the engine rpm rev'd up but no movement, did the same in reverse. I thought it seemed like the prop was gone, but was doubtful, since we didn't hit anything. Fortunately my buddy was heading out and was able to come rescue me and pull me to the Northend of the lake to North Lake Marina (I mention them by name, because they were so very helpful and allowed me to dock overnight). This morning, we pulled it out on the trailer to discover that the prop had definitely sheared off (see pics). Certainly in disbelief that this could occur to such a well designed and very expensive boat.

I am very disappointed for lots of reasons, mostly the fact that I don't have the boat for an unreal stretch of weather this week!
But I am very fortunate when it occurred, as we were out the night before in 20mph wind and that would have been way worse....

It seems, by reading some of the past posts and talking to my dealer, that this is not new to Nautique.
Its difficult to understand why Nautique has not re-engineered the drive shaft, its a real bummer for anyone to deal with, even a new owner that has a warranty. The worst is not having a boat and losing a week or more of summer, which is the only time to use a boat like this in the NW.

[seachicken27]

Going on six years of props falling off. What if Ford made a car that had frequent driveline failures? Would this be acceptable to the consumer for six years? I know we all like our boats, but dang Nautique let's get it together.

[greggmck]

2018 G23 - Prop Sheared Off

Proud new owner of a 2018 G23, purchase one week ago - 6.30.18 (Reside in Seattle / Lake Washington)
Yesterday the prop sheared off, and wow was I shocked. We were out with friends (7 on-board) doing a lazy cruise Lake Union, then headed for Kirkland, ramped up to 30mph crossing the lake. As we approached the marina, I started to back off, there was a slight shimmy or vibration at about 10mph and then I felt or heard a clunk, a slight rev of the engine and then no propulsion. I had no clue what occurred, but when I engaged to move forward the engine rpm rev'd up but no movement, did the same in reverse. I thought it seemed like the prop was gone, but was doubtful, since we didn't hit anything. Fortunately my buddy was heading out and was able to come rescue me and pull me to the Northend of the lake to North Lake Marina (I mention them by name, because they were so very helpful and allowed me to dock overnight). This morning, we pulled it out on the trailer to discover that the prop had definitely sheared off (see pics). Certainly in disbelief that this could occur to such a well designed and very expensive boat.

I am very disappointed for lots of reasons, mostly the fact that I don't have the boat for an unreal stretch of weather this week!
But I am very fortunate when it occurred, as we were out the night before in 20mph wind and that would have been way worse....

It seems, by reading some of the past posts and talking to my dealer, that this is not new to Nautique.
Its difficult to understand why Nautique has not re-engineered the drive shaft, its a real bummer for anyone to deal with, even a new owner that has a warranty. The worst is not having a boat and losing a week or more of summer, which is the only time to use a boat like this in the NW.

Did you call your dealer? They can repair it in 2-3 days. I had the same issue and got my boat back with an updated shaft (shorter keyway) in two working days. See my earlier posts.

[Quailhii]

Yes. Thankfully, my dealer (Desert Valley Power Sports) was in town that same evening, towed the boat back to Prosser and should have it back tomorrow evening, with new updated shaft and prop. Super fast, which I am grateful. Still think that Nautique needs to formally address this....

[cmerritt]

Another broken shaft... 2017 G23 with H6 engine and 162 hours. I was using the acme 2749 prop 17x14. I felt a slight vibration when turning around in surf mode and a rider on the wave. Once I straightened out the vibration got worse. I was just about to stop and my rider fell coming across rollers. I stopped let the waves pass and then when I went to put the boat back in gear rpms just went up. I immediately knew what happened as I had seen this thread just a few weeks ago. My dealer is awesome with getting parts to me quickly but seriously Nautique? It looks like this has been an issue since 2012 when the '13 models came out. I previously had a mastercraft x-star and the G is Hands down a better boat in ever other aspect. I did have some problems with the Mastercraft but never got stranded on the water like this. I also had the issue with the engine idler pulley bearings freezing and shredding a pulley. This left me stranded too. Nautique said it was a known issue there as well from Pcm and they covered it under warranty. 2 times now stranded on the water and I haven't even had the boat a year yet.

[JoeCos]

Wow. I find this thread amazing. Amazing in the sense that Nautique has NOT addressed the issue. It must absolutely suck owning such a fantastic boat, and the shaft shearing off, and that Nautique knows there is a problem, Yet, no solution 5 years later. I dont own a "G" boat, but own an older nautique and been following this thread from the very start, to see if there will ever be a solution.

What the heck is going on?

[Tallredrider]

Another broken shaft... 2017 G23 with H6 engine and 162 hours. I was using the acme 2749 prop 17x14. I felt a slight vibration when turning around in surf mode and a rider on the wave. Once I straightened out the vibration got worse. I was just about to stop and my rider fell coming across rollers. I stopped let the waves pass and then when I went to put the boat back in gear rpms just went up. I immediately knew what happened as I had seen this thread just a few weeks ago. My dealer is awesome with getting parts to me quickly but seriously Nautique? It looks like this has been an issue since 2012 when the '13 models came out. I previously had a mastercraft x-star and the G is Hands down a better boat in ever other aspect. I did have some problems with the Mastercraft but never got stranded on the water like this. I also had the issue with the engine idler pulley bearings freezing and shredding a pulley. This left me stranded too. Nautique said it was a known issue there as well from Pcm and they covered it under warranty. 2 times now stranded on the water and I haven't even had the boat a year yet.

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).

[H2O]

I am wondering if the relatively long strut contributes to the failure? These boats with large diameter props appear to have a longer strut than the older boats without failures. The strut is made from a rather soft metal and could possibly induce harmonic vibrations in the shaft. Similar to certain crankshafts breaking when harmonics play a role at specific RPM but are otherwise robust. It may not be the shaft itself that is at fault but rather harmonic vibration.

[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.

[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.

[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

[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

[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

[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.

[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