Is this normal? Shaft movement- short video

[mncruiser]

Before I ask some follow up questions about things related to the shaft seal, is this shaft movement normal? https://youtube.com/shorts/f4H9Zn3c9eI?feature=share

Specifically asking if the shaft seems misaligned or is this normal movement? I never paid attention to it before. Thanks

[tiltrider1]

It’s hard to tell from just a video. Was that cruising speed? It doesn’t look catastrophic to me but it could be better. I am curious, can you feel the oscillation in the boat?

[HopCar]

I don’t think it’s an emergency but I’d check the shaft alignment pretty soon. There are a bunch of YouTube videos on how to do it.

[C lectric]

Agree about the speed , need to know.
I've seen worse but that can still be reduced most likely.
THe less wobble the better for the gear box.

[mncruiser]

That's at the dock, in gear, about 1000 RPM. Idle is less..not sure, maybe 850?

[mncruiser]

Originally Posted by tiltrider1

It’s hard to tell from just a video. Was that cruising speed? It doesn’t look catastrophic to me but it could be better. I am curious, can you feel the oscillation in the boat?

At the dock, in gear, about 1000rpm. 850 is idle. No vibration evident.

[kchace]

It may not cause vibration but it’s not right. The shaft should not wobble like that. It’s probably not a huge problem but it should be checked as soon as possible to find out the cause.

Ken

[syjos]

It doesn't look like it's too far off, but I would look into it if it was on my boat.

The water under the shaft appears to be rippled.

[Comodave]

From the naked eye it looks fairly bad. Maybe put a dial gauge, not sure that is the correct name, on it to see how much it is actually moving. It can be a fairly involved job to make sure the shaft is running true. You can take it to a machine shop to see if it is straight. But it could also be the cutless bearings are not in line. But the easiest thing and the first thing I would do is check the engine alignment and see if that fixes the problem l. But I wouldn’t let it go for very long.

[mncruiser]

More details about why I asked about the vibration-

Boat launched this morning, this is my first launch as the owner. Boat purchased last year, I was too excited and wasn't looking at anything...call it new boat euphoria?

Well they dropped the boat in, I started it. Did not even get it into gear, and noticed the shaft seal was leaking quite a lot. Not like sinking in 5 mins, but a slow faucet stream. Until today, I really didn't understand shaft seals and how they worked, but I'm learning.

Marina tech says seal is shot, but there's a spare on the shaft. Sweet! Pull into slip, 45 mins later tech comes down, cuts old seal off, slides new one on.

Well the seal still leaks....very very little..but at idle in forward, maybe 1-3 drips per second? Up the idle to 900 or 1000 in fwd, zero leaks. Neutral? No leaks. Reverse at idle, no leaks. I have not taken the boat out. Icebergs still floating around Lake Superior, and the Coast Guard didn't even have their boat in.

Should I be concerned about the leak? Is it because it's cold? 41 degrees and sunny today. Probably colder in the bilge. When they first put it in, it was leaking a lot. Ran at idle in gear, now in current state described above.

Things I do know:
- Shaft, coupler and seal were new in August of 2018. A grounding event by previous owner.
- All work done by a high end marina by previous owner. I have every work order.
- Shaft seal is a "Tides Marine" model K1750. It is this seal exactly: https://www.tidesmarine.com/ws/index...product_id=310

I don't think it was leaking at all last year, but I did have a little water down there I just never got around to figuring out.

How concerned should I be? I understand to replace this now since I used the spare is a drop the rudder, pull shaft sort of deal. Also the vibration....how concerned do I need to be? Going to ask the tech to come look at it tomorrow and get their thoughts.

Thanks for you thoughts!

[Comodave]

If the boat had a grounding then that would make me more anxious to have it checked out completely. How do you know the yard that did the repairs did it properly? Did they replace or straighten the shaft?

[Arc]

It’s not right and the dripless will wear prematurely. I would be concerned with catastrophic failure of the bellows.

[mncruiser]

Originally Posted by Comodave

If the boat had a grounding then that would make me more anxious to have it checked out completely. How do you know the yard that did the repairs did it properly? Did they replace or straighten the shaft?

The shaft was replaced. The repairs were detailed well and also a focus of my survey when I purchased the boat. No issues were flagged at that time.

I also have all the work orders, and talked to the people that did the repairs. I believe it was done correctly.

[BruceK]

So, all ok before hauling out for winter but, not ok on relaunching. Why?
Unsupported load on seal while up? Seal now described as shot. How did it change?
Was alignment checked after an initial period of running? Maybe by PO, via repair techs? Should it have been checked?

Plenty of water has gone under the keel since August 18, and although you understandably got in another tech, having the marina who did the 2018 work take a look makes sense, if feasible.
Either way, alignment needs checking.(Always wondered how shipwrights work to thousands of an inch doing alignments.)

[SteveK]

Originally Posted by mncruiser

The shaft was replaced. The repairs were detailed well and also a focus of my survey when I purchased the boat. No issues were flagged at that time.

I also have all the work orders, and talked to the people that did the repairs. I believe it was done correctly.

From the bolded I expect that it was a true shaft until coupled with the tranny. That plus it was not aligned in the water after a period of time at rest. Get it aligned while in the water.

[Comodave]

Originally Posted by mncruiser

The shaft was replaced. The repairs were detailed well and also a focus of my survey when I purchased the boat. No issues were flagged at that time.

I also have all the work orders, and talked to the people that did the repairs. I believe it was done correctly.

This issue should have been flagged. If it is this visible in the video then the surveyor should have seen it.

[mncruiser]

Originally Posted by BruceK

So, all ok before hauling out for winter but, not ok on relaunching. Why?
Unsupported load on seal while up? Seal now described as shot. How did it change?
Was alignment checked after an initial period of running? Maybe by PO, via repair techs? Should it have been checked?

Plenty of water has gone under the keel since August 18, and although you understandably got in another tech, having the marina who did the 2018 work take a look makes sense, if feasible.
Either way, alignment needs checking.(Always wondered how shipwrights work to thousands of an inch doing alignments.)

Maybe all was not ok before. I’m not sure as I didn’t pay a lot of attention to it until now. We ran 50 hours delivering the boat here, and probably another 100-150 with no issues, but again maybe there were but I didn’t notice.

What do you mean by “unsupported load on seal while up”?

I can ask about the alignment by previous techs. Previous marina is in Charlevoix, MI. I’m 50 hours by boat away from them now.

Having it looked at tomorrow for initial diagnosis, will ask for a thorough alignment check beyond my stare.

[mncruiser]

Some additional observations on vibration.

It’s cold here. 41 yesterday. The engine is a Yanmar 6LP-STE. On cold startup, the boat vibrates a lot, while in neutral. After a long warm up, it settles.

The ripples you see in the water in the video are there when in neutral or in gear. I’d say things actually quiet down vibration-wise when in gear at idle.

The only time I’ve noticed excessive anything is with a rare WOT burst. But between all the noises associated with that, didn’t notice anything crazy.

[Gdavid]

Check for movement at the transmission output shaft flange and prop shaft flange connection. If you can move it up-down or side to side by hand, something is not right. I'm not sure about your ZF tranmission, but on my old velvet drive (which is a completely different animal), the nut securing the transmission output flange was backing off and this caused the bearing to have insufficient preload, it was rather simple and cheap fix but was causing a lead at the output seal and excessive shaft movement.

[Redhook98]

Start with a re-alignment before anything else. Always start with the obvious basics. They are often the most overlooked. But that wobbling is not good.