Prop IS GONE … At bottom of KY Lake

Hey, a belated thanks to Marty, Art, and Tim. I apologize for the delay in posting this up, but after this occurred on our final day of our annual summer vacation (Aug. 7th), I had to tow both our SN and the family home back to Colorado and then head out for nearly 4 weeks of extended travel. I have just returned and I am ready to deal with this issue (i.e., getting it repaired and ready for next year) and, like I told Marty on the telephone back in early-August, I appreciate all the kind words as to no one in our family getting hurt!!! Seriously … I was in the water and had just popped up on the ol’ slalom with my wife driving and our 3- and 5-year-old children acting as spotters). As for the diagnosis, I also appreciate both Art’s and Tim’s perspective and insight … who knows!? I DO know that our ’94 was celebrating its 20th year this summer and that with our 5- and 3-year-olds we had been doing a lot of slow churning at 10-12 mph with the ski trainer and … gasp … “towable” during our trip (with great breaks for mom and dad to ski at 30+ mph)—I was fanatical about checking the prop, strut, and the alignment!!! I also know that our KY vacation is the only time that our boat remains in the water for any amount of time … i.e., we don’t take it out for the two weeks of our vacation as it sits in a extremely protected slip (so I didn’t have a chance to look at the prop and drive shaft like I normally do on a daily basis).

As Marty suggested, I have set out both my initial e-mail along with both Art and Tim’s responses below (again, my thanks to you all) … also Marty’s:

My initial e-mail to Marty:

BUT LOOK AT THIS ...



happened this a.m., our last day here. Any ideas? Metal fatigue? There were no contributing factors (i.e., alignment issues, a strike of some kind ... etc.). It was the first pull of the day, I had just popped out of the water and we were on our way to ski speed (approx. 30 mph) with my very capable wife driving. According to her, she said that over the course of about 3 seconds, she heard a rattle, then a much louder rattle, then nothing ... she immediately shut the boat down. Thoughts? I will of course post this up on CCF as I am anxious to learn the possible causes. No other damage (whew!!!) but a very nice 1-year-old prop is one the bottom of the lake and, I am sure some pending damage to my wallet (any idea of what this is going to cost to make it right?). Paddled/pushed/swam the ol' Nautique over to the ramp and hand loaded her ... heading back to CO in the morning. Hope that you are well!

-B

Art's response via e-mail:

“Thought I'd turn around and send this to "all." Someone please copy it to CCF. I want everyone to know that it was common back then, but with the new keyways it is very, very rare. BTW, if you try to use an old key with sharp corners in a radisused keyway, you'll have trouble. Get the ones with the rounded corners OR take the corners off on a grinder then clean it up on sandpaper.

Marty.... Unquestionably Low Cycle Fatigue. Learned a lot about this during the short period I worked for Pratt & Whitney Aircraft.

If you look carefully at the broken end of the shaft, you will see striations radiating from the corner of the keyway. That is called the origin of the fatigue, and, unfortunately, it's pretty common in 17-4PH stainless steel. It can be avoided by putting a radius on any inside corner as we do now with our prop shafts, starting about 10-15 years ago.”


Tim's response via e-mail:

“Misalignment, bent shaft, bent prop, worn strut bushing, excessive prop to strut clearance... Take your pick- could have been any of the above or a combination thereof. Bad metallurgy on the shaft is possible but not likely. Not sure how he could rule out those not being factors unless he is 100% sure the driveline maintenance was up to snuff from the day that shaft was installed.

New $300 shaft/coupler and $400 prop and he's back in business.”


And, of course, Marty (thanks Pal):

“Yeah--- It’s complicated to hear… But most guys are gonna say misalignment….. That’s a hard one for me to say- since it’s the end of the shaft….. Maybe a taper issue. If we had the other end- then you could verify if metal fatigue …. Is there any burning on the end of that shaft ? But Art can verify now- that metal fatigue could have played a part and it’s nothing you did wrong or nothing you could have done to prevent this…. Like you said- Hope shut it down quick and the most important thing- NO ONE WAS INJURED !! Just the Beatte Family Pride and Wallet J

When you post it—you can COPY what Art wrote- and just be ready for about 6 different answers..

Be Safe and keep me informed ….”


Ok, now to THE important issue. Although this is only our third season of ownership, I hope to keep this boat in our family for another 20 years. What, specifically (i.e., specific parts … part numbers if you have them) do I replace while I am at this repair? I have a trusted boat mechanic but I want to expedite the process. I am also considering installing a dripless PSS “Shaft Seal” system. I will thank you all in advance for specifics.

Thx. Not a single vibration or an "off" note of any kind. That's a beauty you've got MrMcD.

Good to hear no damage other than your wallet. ARE shaft is the way to go for replacement. Gortex packing will do 95% as good as a dripless packing.

Eddie, point well made and I understand … I am ready to get on with the repair and do it correctly! Thx.

I should get credit for one of Joe's, and I was on Eddie's boat several times last year, which means his will probably go in the next 5 months...my guess, Feb 7th.

Any hit on the wallet sucks, but at least it was day 14 of the vaca, not day 1. If everything worked all the time, what would we talk about?

backfoot100 wrote: You make it sound like it's the equivalent of an alien invasion that nobody has ever experienced before. The shaft broke. It happens. Get over it.

Ah, compassion for our fellow boaters...

gsyogi wrote: Thx. Not a single vibration or an "off" note of any kind. That's a beauty you've got MrMcD.

I had never heard of the shaft snapping without an alignment issue or bend in 30 years of tournament boat use. I guess I have been lucky.
1,500 hours on my first Nautique. 800 Hours on the Malibu.

Thanks for the kind words about our 95, unfortunately it was in a car accident and is waiting for repairs, formerly unscratched now needs gel coat repair, trailer repair, new prop and more. There is a thread with pictures of the damage, could have been much worse no one was hurt. ( not even the deer )
Your fix will be straight forward, good thing your prop did not come up and damage the hull. I used the Acme shaft on the 95 and it was very high quality and shipped really fast. There is a 10% discount available if you use our membership on this forum.

A.R.E. shafts

Acme propellers

backfoot100 wrote: John lost a practically brand new 540 in TN a few years ago and the shaft looked identical to yours. No warning, no vibration, just gone. Get a new double taper Acme shaft, coupler and prop. Put it back together and have fun.

seemed like it was real easy to put it all back together..at least Eddie made it look easy. I just watched & tried to stay outa the way.



john

Hollywood wrote: A.R.E. shafts Acme propellers

Hollywood is correct, I advised badly. A.R.E. for the shaft including a new coupler was $375 from Discount Inboard Marine, Ski DIM when I bought mine in January this year. It is an improved coupler and easy to work on if needed. Good time to check the cutlass bearing in your strut, makes sure it is still tight before ordering parts.

gsyogi, of course I'd like to look at it.
Close up pics would most likely also do.

Brian has his boat fixed up and ready for the yearly Family vacation in Kentucky- but has a few questions. 1st he's having an issue with posting it here- so I'm gonna try.
He had a new shaft and prop installed. Also went with the PSS Drippless System. It's plumbed above the outlet on the RWP. Is this correct ?
Also it has a collar that is up against the graphite bushing. It seems like it's a safety collar- but I didn't think it should be up against that bushing.
The mechanic said his strurt and strut bearing was good. He has slight movement in that area.
I'll try and get pics up..
Any help in this matter is appreciative by him and helpful in me gaining knowledge on it also.

MartyMabe wrote: Brian has his boat fixed up and ready for the yearly Family vacation in Kentucky- but has a few questions. 1st he's having an issue with posting it here- so I'm gonna try. He had a new shaft and prop installed. Also went with the PSS Drippless System. It's plumbed above the outlet on the RWP. Is this correct ? Also it has a collar that is up against the graphite bushing. It seems like it's a safety collar- but I didn't think it should be up against that bushing. The mechanic said his strurt and strut bearing was good. He has slight movement in that area. I'll try and get pics up.. Any help in this matter is appreciative by him and helpful in me gaining knowledge on it also.

Marty where he has it plumbed in is perfect nice cool water going to the seal.
The collar should be moved up the shaft some so it's not touching.
The movement in the strut bushing should be very minimal if any. Since it's the old bushing it has some wear on it. If it were me I would have changed that also while he had everything apart don't know why his guy didn't do it.

Well here's a video of an install.. I'm perplexed as to how that 'collar' doesn't wear on the snout of the PSS System when it's preloaded and right up against it! ??? Guess the water keeps it lubricated and cool ????