Can a worn Gori prop cause vibration?

[sharmajm]

Hi, I have a 1993 Dehler 34 with a well worn Gori 2 blade folding prop. I am getting vibration at certain speeds under power and am trying to work out whether I need to change the prop or the engine mounts or maybe both.

I would be interested in everyone views.

Regards

Jon

 

[rudolph_hart]

Yes.

Although both of my D34s had 2-blade Gori folders, they weren't worn in my ownership.

However, my D35CWS' Volvo 3-blade folder did wear enough to cause vibration. The wear was in the pins, so I had a local machine shop make oversize pins & redrill the boss to suit.. Not an expensive job & gave me about 6 or 7 seasons, before the wear on the teeth allowed them to jump, so the blades opened asymmetrically. This was great fun - NOT -nearly shook out all me fillings . Bought a Bruntons 3 blade Varifold- smooth as silk.

Back in the late 70's, I had a 3/4 Tonner (31ft) with a 2-blade folder which suddenly did the same thing off Hook of Holland at 5.00am & the vibration broke the P-bracket

 

[V1701]

Check Cutless bearing and/or P bracket bearing?

 

[sharmajm]

Thanks both of you. I checked the cutlass bearing and there is no play in that. There is not obvious damage to the engine mounts, but engine and propshaft seemed to be moving more than I am comfortable with so one problem might have lead to the other. I think I will probably change the engine mounts as well.

 

[Tiderace]

As stated yes; had it on a three bladed maxi prop. Suggest you do the enginemounts first as the cheaper of the two incase that solves it. If that doesnt, then go to the prop,

Be worth seeing if it can be refurbished; potentially save a bit of £.

 

[scrambledegg]

I have had word for word exactly the same experience you've had (Gori folding 2 blader, but on a Sigma 362).
I asked a boatyard to take a look, not least because I'd previously spotted that the pretty old Gori had gone pink.
I had vibration at certain speeds and was reasonably certain that the cause was the engine having settled on its mounts - the last time I changed the dripless seal I noticed that the prop shaft was touching the bottom inside surface of the stern tube.
The boatyard removed the prop and it was evident that the teeth that mesh the two blades were well worn and one tooth was missing. This made one blade of the prop open more than the other - so the asymmetry can't have been helping.
They also reported that the engine had settled down on one side and rectified this by adjusting the engine mount bolts.
So I suppose the moral of all this is that there can be multiple concurrent issues causing the vibration!