Shaft Bearing - Only the one.

[KiwiClive]

Anyone having trouble with engine shake?
There is only 1 bearing in the P bracket and then shaft is bolted onto the gearbox.

I have had a bit of engine shake at 2000 revs. It is better now that I have the engine alignment done but it was not an easy job.

 

[Comodave]

Have you checked the props? I like to do the easy stuff first.

 

[KiwiClive]

Have you checked the props? I like to do the easy stuff first.

Yes, all is good underwater.

 

[boater3]

Anyone having trouble with engine shake?
There is only 1 bearing in the P bracket and then shaft is bolted onto the gearbox.

I have had a bit of engine shake at 2000 revs. It is better now that I have the engine alignment done but it was not an easy job.

Lets start with make/model/year Swift Trawler/if twin engine, what side vibrating

I have a ST44. It had a vibration around 1900-2100 RPM since new. I avoided that RPM. Prop checked twice. This winter I decided to dive into it

Yard was sure it was the rear engine mounts so they changed, re-aligned, now vibration worse and a wider range of 1000-2700 RPM. Not good

They removed the shaft, machine shop said its bent (they put on lathe with dial gauge). How that happened who knows couldve been on transport ship from Europe to USA, yard/dealer crane error when boat was being loaded / unloaded, something the first dealer did (i.e. run aground, suck up dock line). The vibration was there day one when the boat was first sold, noted during the initial sea trial, and by Volvo tech that looked over engines to activate warranty. Thankfully I had it clearly documented to support the warranty claim with Beneteau.

Another ST44 owner had a similar vibration on the same side and it turned out to be his shaft-to-coupling fit-to-face and once he had that corrected he was good to go (after chasing it for a long time) but my situation doesnt seem to be that easy.

Lots to check: props, cutlass bearing, strut, coupling, coupling fit-to-face, output flange on transmission, shaft, engine mounts, how prop it sitting on shaft/keyed, etc

Someone with a dial gauge and feeler gauge can check most things. If everything is checked with boat in-water / on the hard, the final step is to remove the shaft and check it as well as the strut/cutlass.

I am hopeful this will finally be resolved soon

 

[KiwiClive]

Hey thanks this is a great help.
I'll start working down the list.

 

[KiwiClive]

Sorry, forgot to answer your question: "Lets start with make/model/year Swift Trawler/if twin engine, what side vibrating"
2018 Swift 44 with twin D4's. port side.

 

[boater3]

Sorry, forgot to answer your question: "Lets start with make/model/year Swift Trawler/if twin engine, what side vibrating"
2018 Swift 44 with twin D4's. port side.

very interesting that this keeps happening on new ST44s

since the boat is so new i doubt the cutlass bearing is bad or engine mounts. so that hopefully knocks two things off the list...

please do keep us posted!

 

[KiwiClive]

Just a thought, are all the 44's running on just the 1 shaft bearing in the P bracket?

 

[boater3]

Just a thought, are all the 44's running on just the 1 shaft bearing in the P bracket?

p bracket = strut?

 

[KiwiClive]

Yes, strut.
On my 44 the shaft has no bearing where it enters the hull.

 

[boater3]

Yes, strut.
On my 44 the shaft has no bearing where it enters the hull.

i think that is correct. the diagrams are on beneteau's spare parts website. i am attaching them here too.

 

[Pcpete]

I’m guessing a tweaked shaft or prop blade. I just went through everything after the transmissions on mine. One shaft was bent .005” beyond tolerance at each end and that coupler had the pilot cut back .010”. In addition, both props had been repitched by someone with a “golden hammer” because the destruction went all the way to the roots. An issue you probably don’t have.

 

[twistedtree]

In addition to coupler faces not being machined square to the shaft, I have heard of bores that are not concentric with the hub body. All are a result of sloppy machining of the hub, and easy to overlook. Running a dial gauge on those surfaces might reveal a problem.

 

[KiwiClive]

i think that is correct. the diagrams are on beneteau's spare parts website. i am attaching them here too.

Hey that is very useful, what is the link to the website?

 

[boater3]

http://spareparts.beneteauusa.com/controleur.php

 

[KiwiClive]

http://spareparts.beneteauusa.com/controleur.php

Looks like it is only available to US customers as my registration didn't go through.
Shame as I would like to see how I can remove the wooden steps up to the flybridge so I can varnish them.

 

[KiwiClive]

I took a video so I can go back to the agent here in NZ and see if they think this is acceptable vibration.
The footage is slowed down as at full speed it is hard to see the shake via video.

Here is the link: https://youtu.be/71wufL2I_bk

 

[Pcpete]

I’m thinking that looks like a long bend in the shaft. It’s not particularly at either end but an arc. I’m probably wrong, but it appears, based on the shot at the PSS moving around. It should be impossible to get a proper alignment at the coupler unless it was matched to the shaft as bent or the bend starts after the coupler. Watch the video at 32-50 seconds, that PSS is still moving and shouldn’t be.
My complements on an unreasonably clean bilge.

 

[ben2go]

Was the transmission to shaft alignment done with the boat in the water? If so, no issue there. If it was done on the hard or in the slings, it could be out slightly.

 

[KiwiClive]

Both.
The last time we did it out of the water and made it true to the strut bearing.

 

[MichaelB1969]

Both.

The last time we did it out of the water and made it true to the strut bearing.

Looks like mine used to look. This would be unacceptable to me, and I'd worry about transmission wear over time.

Did you check to see if it is the same issue I had with the shaft to shaft (not transmission) coupling alignment?

 

[boater3]

I took a video so I can go back to the agent here in NZ and see if they think this is acceptable vibration.
The footage is slowed down as at full speed it is hard to see the shake via video.

Here is the link: https://youtu.be/71wufL2I_bk

that does not look good

 

[Brooksie]

Video: Issues for sure
BTW, I wouldn't trust that piece of clear plastic hose on the seacock below the waterline. May be rated for that duty but I doubt it.

 

[Nomad Willy]

IMO it’s most likely the port shaft.

A shaft that long needs to be very straight to not run out like a jump rope. And no shaft is straight. As a truck driver for a machine shop that did boat shafts I was usually the one that picked up the shaft “downtown” in Seattle. The shaft went straight from my truck to the lathe to get straightened. And they never got them straight. It’s a matter of how close to straight one could get.

So I’d take it back to the shop (or find a better ) shop. It’s the man that does the work that’s important. It’s an art.

Can you swap props?

Another thought is to install a mid span shaft strut. They come adjustable so not that hard to install.

Is this a counter rotating gear box with a slightly different ratio in the two gears? That could set up a harmonic vibration. Sounds like twin engines that aren’t quite sync’ed.

 

[ghost]

I’ve never had one that bad myself. Makes me think my chasing a few thou was almost crazy. Sorry, but I think your going to have to pull the shaft for sure. As always, consider the system. That means starting over, prop needs to be true and balanced, not by eyeball. Then verify the cutless is true. Then align the strut to the shaft log. Then have the shaft trued, or if you can’t, replace. Then have the coupling faced to the shaft. Then align. Even the alignment done out of the water should not have visible wobble like that.

Consider replacing mounts, those have gotten an extreme workout.

Finally, the fact that it has a drip less seal is symptomatic that this has been a problem for some time. No way you could get a traditional stuffing box to work with that, so a drip less may have been a misjudged solution instead of fixing what’s wrong.

If you address as a system, you will solve it, almost by definition. That far out, don’t try to piecemeal it, it will just cause more frustration than it’s worth.

 

[Nomad Willy]

Oh I didn't realize this boat had a dripless seal. May want to consider going back to a stuffing box. If the hose isn't too long and soft it will act much like an intermediate bearing.

 

[boater3]

Oh I didn't realize this boat had a dripless seal. May want to consider going back to a stuffing box. If the hose isn't too long and soft it will act much like an intermediate bearing.

Going back? The ST44 comes standard with Volvo drip-less.