Vibrating shaft at slightly high revs.

[Hoohaa]

I think Cheech was referring to there not being a cutlass bearing in the stern tube.
What length is your shaft?. How much of it is unsupported?

[Hoohaa]

To align correctly you will need to find a way to center the shaft on the stern tube. Assuming the strut is aligned properly

[Hoohaa]

Hi Everyone.
Sorry to rattle this old thread back to life, But! I have some exciting news.
Its been a little over 2 years since I last slipped my boat. In that time I have installed a new engine and spent hours aligning and realigning the shaft.
I have had a diver go and take photos of the back of the stern tube to help give an idea where the shaft was sitting within the stern tube.
The result had the prop shaft running ok above 1600 rpm, so I made do.
This whole time I have never seen behind my stern gland as the boat is always in the water.
I have been preparing for a couple of years now to install a cutlass bearing and new dripless seal on the forward end of the stern tube.
Stern Tube



You can see that the shaft is running low in the stern tube.
The second picture is of the cutlass bearing I have bought to place on the forward end of the stern tube.
So here is what we found when we slipped this morning.

[Hoohaa]

Its a bit hard to see but the 2 pics showing the forward end of the stern tube exposed and with the shaft still coupled to the motor. So this is the current alignment.
You can't see in the pics but the shaft is sitting 5 to 10mm low in the tube.
When I put the cutlass bearing in everything aligned ahhhh.
The shaft is now considerably stiffer and beautifully aligned at both the rear and front of the stern tube.
The last shot is of the cutlass bearing inserted and glued in place.
So its looking good.
There is also another strange thing that popped up and I will get some pics tomorrow. There appears to have been another cutlass bearing inserted in the old stern gland the entire time? Looks weird and is probably the source of the knocking noise.
Jeff

[Hoohaa]

Originally Posted by Hoohaa

Its a bit hard to see but the 2 pics showing the forward end of the stern tube exposed and with the shaft still coupled to the motor. So this is the current alignment.
You can't see in the pics but the shaft is sitting 5 to 10mm low in the tube.
When I put the cutlass bearing in everything aligned ahhhh.
The shaft is now considerably stiffer and beautifully aligned at both the rear and front of the stern tube.
The last shot is of the cutlass bearing inserted and glued in place.
So its looking good.
There is also another strange thing that popped up and I will get some pics tomorrow. There appears to have been another cutlass bearing inserted in the old stern gland the entire time? Looks weird and is probably the source of the knocking noise.
Jeff

Shots of the old stern gland with a built in cutlass bearing.