Shaft Alley Repair Question

[cariedl]

Upon blasting the bottom and inspection it was discovered that both shaft alleys were rotten and needed to be addressed. In my post detailing the project http://www.bertram31.com/newbb/viewtopi ... =2&t=13319 I mentioned using Capt. Pat's glassed in shaft plan to complete the repair.

I've read all the posts I could find using the search function about the fix and the only real benefit I see mentioned is a 1/2 knot increase in speed. I'm wondering, is there any other real benefit to using the tube and glassed in design found here: http://www.bertram31.com/proj/struts/struts.htm?

I also noticed that I have a slight vibration when I shift out of gear into neutral that I believe is caused by the port shaft. I'm also wondering if I choose to use the glassed in shaft design if I need to consider new shafts to ensure that the vibration is eliminated or will there be enough "play" in the shaft tube to accommodate without compromising the integrity of the fiberglass work over time? Ideally, I don't want to replace the shafts unless absolutely necessary.

As always, your input and thoughts are appreciated.

Thanks,
Charlie

[Rawleigh]

Biggest benefit: It is integral to the hull, never rots or goes bad.

[Marlin]

I remember doing that process well, my new spencer has f/g shaft alleys/logs that go all the way back to and become an intergal part of the strut, creating a faired environment to minimize water/air turbulence to keep clean water coming aft of the transom

[Tony Meola]

I know on my boat when we re-powered and put in the glass shaft logs, we were surprised at how thin that area was, and glassing in the logs fixed that issue.

[cariedl]

Thanks for the replies, the comments make sense. I had the marina pull apart the housing and shaft ports where the shafts exit the hull, the brass fitting pictured below on the PORT shaft is worn thin, which likely explains the vibration and can be attributed to the shafts not being perfectly aligned/true.

I now expect that the shaft issue needs to be addressed regardless of the repair method.

[CamB25]

This is a great picture...tells a story!

[1962 31]

I may still have my original shaft alleys if you want them let me know ill dig them out

[Stephan]

Charlie-
Looking at your shaft log again it does not appear shiny or freshly worn where it is thin. Might this be the scar of an old insult to the shaft or log and not something you need to address?
I ended up with a whip in my Starboard shaft which caused vibration and the shaft log to weep.
With Capt. Pat's and Harry Babb's encouragement/direction I was able to straighten it substantially.
http://bertram31.com/newbb/viewtopic.ph ... vibrations
I would like to have gone to the integral fiberglass shaft log but opted to build up the existing glass and reinstall the silicon bronze shaft log.
That was the winter of 2012 and all has been well since.
I hope you enjoy your solution as much as we have. Good luck!
Stephan

[mike ohlstein]

Charlie-
Looking at your shaft log again it does not appear shiny or freshly worn where it is thin. Might this be the scar of an old insult to the shaft or log and not something you need to address?

I agree. You hit a turtle about 70 miles offshore and the shaft log will look like that by the time you get home. You fix the prop, and never look any further...... until you do.

Guess how I know that........

[cariedl]

I may still have my original shaft alleys if you want them let me know ill dig them out

1962 31 - if the offer still stands to dig out your original shaft alleys please let me know, I'll take you up on the offer. PM me reply here and we can figure out the details.

Thanks!

Charlie

[Pete Fallon]

Cariedl,
By the looks of the wear pattern it has been doing it's thing for a while. The shaft might have been bent, the coupling alignment was way off, the motor mount had collapsed, or the wooden stringer where the motor mount was attached to had a rotten spot causing the alignment to be way off. Any of these items could have caused the wear which happened over a long period of time. It's always a good idea to check your motor mounts, stringers, alignment and shafts for true every year before launch or when you paint the bottom. an other cause could have been a bent prop blade or a worn key way. Check the shaft for wear also take a look at your cutlass bearing for wear pattern, if the shaft log is that worn check the strut to see if it's bent.
Pete Fallon