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[Bob K]

Interesting problem.  I have a twin prop HMS Amazon (1906) that has been sailing successfully for almost two years, once or sometimes twice a week.  The port shaft started sticking so I thought it was high time I stripped both shafts for a !0k mile service.  However on trying to strip the 2mm dia port shaft I found it was irremovable, turning with a distinct ratchety feel.  Prognosis:  the ball race appears to have failed.

Having tried to drive it out with no luck I am having to consider cutting the whole assembly from the hull, which could be a major mess as the shaft outer is epoxied into the hull and A frames.  I could try cutting off the bearing end and fitting a new end with a brass sleeve?

Any ideas ?
 

[Shipmate60]

Do you just want to replace 1 shaft or both?


Bob

[rnli12]

Hi,
Trying putting heat into the shaft around the bearing housing either using a heat gun or soft flame, just mind the model!
Worked for me.
Regards,
Rich

[Bob K]

Do you just want to replace 1 shaft or both?

Bob

I was hoping to fix the sticking shaft and lube the other, although if the shafts ended up too dissimilar it could affect how the ship runs.  Due to limited space the shaft fore ends are below the waterline, which is why I opted for more expensive watertight ones with bearings.
 

[john44]

Hi Bob,
I would clamp the hull on its side on the bench,slide a rod or old shaft
into the tube and upto the bearing/bush.
place a plumbers braising mat or wet rag, under the shaft to protect the hull
and A frame
warm up the end of the tube with a small blow torch and then give the rod
a tap and the bearing should come out easily,(You should NOT have to heat it
to red hot). then just replace the bearing and re paint the shaft.

Place something heat resistant under the hull for the hot bush/bearing
to land on to prevent any risk of smoldering.
I have done this on a few occasions for both top & bottom bearings or bushes
where access allows.

I have also removed the whole shafts using the heat method,
heating the shaft up, you don,t have to get too near the hull because
the heat transfers down the tube, hold the tube with a pair of pipe
grips/pliers,etc. and keep the heat on whilst gently trying to turn the tube
the hot tube breaks the bond with the epoxy and you can slide it out,
you will find that there is very little or no damage to the boat and a new
shaft can be slid straight in and sealed.

Use this method ONLY on wooden or fiberglass hulls.

hope this is a help

john

[Shipmate60]

John,
Just one thing to add.
If you are not removing the shaft put something as a large heat sink to stop the heat transfer into the shaft in the hull.
It doesn't take much heat to remove the whole shaft.
I was thinking of just removing the shaft this way and replacing with the same.
Might be better to see if there is any lubrication of the bearings required.


Bob

[Bob K]

Interesting.  Thank you all for the suggestions.  Using a flame gun in very close proximity to the hull sounds a bit fraught.  See photo posted earlier.  From this picture during build sequence the bearing end cap looks to be yellow plastic.
 

[Shipmate60]

Use a large Iron for heat.
But if you want to remove the cap just cut it off if it is plastic.
What are the "A" frames made of?


Bob

[Bob K]

What are the "A" frames made of?

Bob

Unfortunately, fabricated around the shaft in ABS and Plasticard.
 
What I might try first is to buy two more of the same prop shaft assemblies, then try to 'pull' off one of the end caps, which with luck may have the bearing embedded in the plastic.  If that works I can cut the plastic off the damaged shaft, clean up, then tap the cap/bearing onto the shaft in situ.
 
If that doesn't work then I'll go for the heat method, and reconstruct the A frame.