Tranmission / Coupling Installation...C30 - SailNet Community

   Search Sailnet:

 forums  store  

Quick Menu
Boat Reviews  
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Hatches and Portlights
Interior And Galley
Marine Electronics
Other Items
Plumbing and Pumps
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here

Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
Old 03-19-2013
Join Date: Sep 2011
Posts: 41
Thanks: 1
Thanked 0 Times in 0 Posts
Rep Power: 0
sfbaysailing is on a distinguished road
Tranmission / Coupling Installation...C30

Hey everyone

We have our 1976 Catalina 30 "Amici" hauled out to do a bunch of work, including replacing the cutlass bearing....which required cutting off the old prop shaft coupling and buying a new split coupling.
Engine is a Yanmar 2GM. The machinist squared the face of the coupling to the shaft, and when i went to install it yesterday the faces of the shaft coupling and the transmission output flange would not meet...there was a 6mm gap in between.

Looking closer, I could see that:
1) The tranmission output shaft sticks out proud of the flange
2) the prop shaft sits proud of the "inner" face of the shaft coupling (the coupling has a recessed area in the middle to mate with the transmission...and the shaft is proud of that recessed part, but not proud of the "outer" face of the coupling). I seemed to remember that previously, the shaft was flush with the inner face of the coupling...but im not sure.

It appears that i need to either:
1) move the shaft forward in the coupling, which is not possible bc of the location of the set screw
2) cut the shaft shorter
3) adjust the tranmission output flange so that it moves further aft and the shaft is no-longer proud of the output flange face.

Does anyone have any ideas about which of these is the natural state of things? Should the shaft be flush with the "inner" face of the flange? Should the tranmission output shaft be flush with the face of the output flange? Anyone have direct experience?

Thanks so much for your help! We are trying to splash her today
Reply With Quote Share with Facebook
Old 03-19-2013
eherlihy's Avatar
Learning the HARD way...
Join Date: Jan 2007
Location: Boston Area
Posts: 3,557
Thanks: 114
Thanked 64 Times in 63 Posts
Rep Power: 8
eherlihy will become famous soon enough
Re: Tranmission / Coupling Installation...C30


It seems that the setscrew "dimples" have been machined too far back along the shaft. When I did this job last year, the end of the shaft was set into the coupling by about 1/8". You can read all about that adventure here; Contemplating a drive line overhaul

I suggest bringing it back to the shop that did the machining, and ask them to correct the problem. I suspect that they will want to simply cut the shaft. You decide if this is acceptable to you.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

USCG Licensed OUPV Captain, ASA 101/103/104/105 Certified Instructor - Also certified in Recreational Marine Electrical Systems
Reply With Quote Share with Facebook
Old 03-19-2013
T37Chef's Avatar
Senior Member
Join Date: Oct 2006
Posts: 4,259
Thanks: 71
Thanked 34 Times in 31 Posts
Rep Power: 9
T37Chef will become famous soon enough
I don't think you're going to splash today Did you send the coupling with the shaft and have them fit the coupler? if not that's probably what you're going to have to do. could you post a picture?
Reply With Quote Share with Facebook
Old 03-19-2013
Join Date: Sep 2011
Posts: 41
Thanks: 1
Thanked 0 Times in 0 Posts
Rep Power: 0
sfbaysailing is on a distinguished road
Re: Tranmission / Coupling Installation...C30

Hey guys

thanks for the quick replies.
I did bring the shaft and coupling to the shop to have them fitted. The shaft actually had two sets of set screws, one at 180 degrees to the wundruff (sp?) pin, and the other two at 45 degrees to either side. The existing coupling used the two set screws at 45 degrees, and was a fixed coupling (not split)

The new one utilizes the single set screw dimple, and is a split coupling.

I think you are correct and you used the wrong dimble, thereby pushing the end of the shaft forward. It just seems strange because the machinist seemed very conscientious, and we even talked about which coupling would work based on the location of the set screw dimples!

thanks again guys, will post more as i know ...but just knowing that the shaft should be flush with the inside of the coupling is the most important thing

Reply With Quote Share with Facebook

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Similar Threads
Thread Thread Starter Forum Replies Last Post
SPLIT-HALF COUPLING - replacing old keyway'd coupling SailMonkey Gear & Maintenance 10 09-07-2012 08:34 AM
Albin ad-21 tranmission tmiron Diesel 1 04-16-2012 12:06 AM
Leaking coupling my900ss Atomic 4 7 06-15-2011 11:26 AM
Yanmar 2QM20 tranmission- substitutions? hertfordnc Gear & Maintenance 1 01-19-2009 05:29 AM
shaft coupling clifsail Announcements and Suggestions Box 1 08-15-2006 02:06 PM

All times are GMT -4. The time now is 11:07 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) LLC 2000-2012

The store is owned and operated by a company independent of the forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.