Big Boring Job!

[jackieschmidt]

One of our Customers, G&H Towing, is doing a major refit on this vessel, discovering the Port Strut Bearing to be about 1/2 inckph out of alignment with the Stern Tube.

The shaft is 11 inches, this hole already had a sleeve in it. The cut it out, I am align boring the Strut Barrel back in alignment with the Stern Tube and the Reduction Gear.

I will have to take it to about 14 1/2 inches to clean up. We will then machine a new 42 inches long insert to press into the Strut Barrel, then the bearing into it.

I figure to be here, (Port Neches), for about three working days.

 

[F Class John]

Jackie we don't know each other but the boat stuff you post just blows my mind. First, because I didn't even realize fixing this kind of stuff was even a thing and second, because of the skill and experience it must take to get it done right. Amazing.

 

[topclass2017]

the scale of what you work on would be hard to grasp without the pics. Seeing the tugs out of water helps understand how it is that they can move ships around.

Thank you!

 

[ShtrRdy]

I'd like to ask questions but I don't know what things are called . I think I understand the basic problem being fixed. The shaft coming out of the hull is supported and pointing in the right direction? But the support bearing in the strut is out of alignment? What is the round collar called that the propeller turns in? Please feel free to correct my naming of things . I did understand what 'port' meant.

(I live in the middle of the US. Far from any ocean)

 

[tobnpr]

discovering the Port Strut Bearing to be about 1/2 inch out of alignment with the Stern Tube.

Was it built that way, or did they hit something that bent the strut?

We will then machine a new 42 inches long insert to press into the Strut Barrel, then the bearing into it.

So the hole in the insert for the cutless bearing will be off-center?
Guessing re-alignment of engine/trans is required...
I'd grimace stroking checks for a little 40 footer. Can't imagine the maintenance and repair costs for big boys. I'd probably have a stroke over the cost of shaft seals alone for 11" shafts

 

[jackieschmidt]

Was it built that way, or did they hit something that bent the strut?


So the hole in the insert for the cutless bearing will be off-center?
Guessing re-alignment of engine/trans is required...
I'd grimace stroking checks for a little 40 footer. Can't imagine the maintenance and repair costs for big boys. I'd probably have a stroke over the cost of shaft seals alone for 11" shafts

After I am finished, everything will be where it is supposed to be.
They will not know if the Reduction Gear will have to be re aligned until the boat is in the water. That is a major project in it’s self.

As to how things got amiss, that seems to be a mystery. The Kort Nozzle, Stern Tube, Shaft Seal and gear all are in alignment. The Strut Bearing is the only thing that was out of alignment with everything else.

As for the Shaft Seals, this vessel has been converted to the Thordon Seal. I believe they are around $25,000 each. Once installed, they are trouble free and let no water in.

 

[jackieschmidt]

I'd like to ask questions but I don't know what things are called . I think I understand the basic problem being fixed. The shaft coming out of the hull is supported and pointing in the right direction? But the support bearing in the strut is out of alignment? What is the round collar called that the propeller turns in? Please feel free to correct my naming of things . I did understand what 'port' meant.

(I live in the middle of the US. Far from any ocean)

The bearing at the hull is called the Stern Tube Bearing. The large ring surrounding the Prop is called a Kort Nozzle.
When it is all put together, four things have to be in true alignment. The Strut Bearing, the Stern Tube Bearing, the Shaft Seal, and the Reduction Gear out put flange.

Here is what the fresh bored strut looks like after I finished yesterday evening. The three stepped fits allow the shipyard to insert the big steel sleeve in 2/3 the way before they have to press it. I will give the sleeve around .002 interference fit.

 

[AlNyhus]

Amazing work, as per usual! -Al

 

[ShtrRdy]

Thank You Jackie! I appreciate you taking the time to explain some of this.

Take care -- Todd