It finally works

[msmith10]

I developed a bothersome vibration in the drive train and visible wobble at the stuffing box last season. No amount of alignment would correct it and I finally decided last fall to pull the shaft and take it to a shop to check the shaft and coupler. Although the alignment was within 3/1000's on multiple checks I suspected the coupler face was not square and this in fact was the case. In addition I wanted to replace the rubber tube portion of the shaft log which I think was probably original to the boat and 35 years old. It had become noticeably soft.
The new tube, which is considerably beefier than the old one-- 5 plies and about 1/4" thick, worried me that I wouldn't be able to clamp hard enough to seal well.
I'm happy to report that the installation is complete (note to self-- next time remember to put the packing nut on the shaft BEFORE driving the coupler onto the shaft), the result is leak-free, alignment within 2/1000s, absolutely no vibration in the stuffing box. I'll have to realign after she's been in the water
overnight and the rig is tensioned and tuned, but it's as close as I could get it on the hard.

[sastanley]

Mark,

Great news....my question is, how did the coupler get out of alignment? Was the key loose, or maybe the locknut?

[msmith10]

I don't know how the coupler face got out of square. It was certainly corroded onto the shaft very tight, but once I got it off, I slid it back onto the shaft and the fit was loose enough that I knew it couldn't have been square while it had been installed. It may have been out of square for a long time, but I doubt it. At the beginning of last season I noticed the vibration immediately which led me to suspect that the yard had caused the problem somehow, possibly by getting a lift strap across my prop shaft. However, I would think the shaft would have bent rather than distorting the shaft to coupler fit. I suppose it will remain a mystery.

[ArtJ]

Some boatyards are notorious for hiring the cheapest labor they can get
and charging through the teeth for it. Whenever possible I do my own
work or else monitor them very closely.

[msmith10]

I agree. I do almost everything myself. I can't run the lift, though.

[Dromo]

I also agree, I thought my prop. shaft might be bent.

It was out by maybe a 1/8'' , 32.5 '' long;
I removed it , brought to the machanic shop run at our marina, asked if it could be straighten..

They had it for a over week, said I needed a new one and would cost around $600. plus tax.

I ended up ordering one from deep blue yacht supply for $345. and thats with the cost of shippng to Canada included

Having said that, I was trying to buy a shaft and these guys were trying to give me the shaft.
Cheers Rick