Prop Shaft Replacement

[Stephen Butler]

Finally back into the message board.  Must sincerely thank the association for all the advice in getting our 1990 C34 ready to sail....3 weeks of sailing this past summer was great, thanks to the information provided!  

Now, for the next project: changing out the prop shaft and cutlass bearing.  The problem is that we want to order the replacement parts from Catalina, but are told that we need to first specify a prop shaft length.  Our plan is to pull the boat from the water, change out the shaft and bearing, and be on our way to Key West...all in a day or two.  We cannot see how we can get the boat out, measure, order the parts, receive them, install them, and still meet our schedule.  Can anyone suggest a prop shaft length that is more or less "universal"?  We can always saw a bit off a shaft if need be.

We are also in need of a steaming/deck light fixture and a mast boot.  Any suggestions or should we just order these from Catalina also.  

Thanks for the advice.   Steve and Nancy on Wildflecken II

[Stu Jackson]

Steve

It's a one inch shaft.  Unless somebody knows the actual dimension for a 1990 boat (HULL #???), you actually should be able to measure it from scale from  blowup of the catalog side view of the boat in the Brochures section.  You can't be far from wrong, just add a bit.  If there's someone near you you could measure it horizontally assuming the water is clear to see where the pop is, but bring the drawing, too.  Those are the only ways I could figure to measure before you haul.

For the steaming deck light and the mast boot, go to BoatUS and West Marine.  Easier and probably less expensive.  You should be able to tell what kind of steaming light you have by comparing it to the catalog pictures: Forespar or Aqua Signal.

[rirvine]

While you are going to the effort of replacing the prop shaft, you should upgrade to a stainless shaft.  I would suggest you search this site for information on the various options for actually doing the work of the replacements so you know what to expect.

Regards, Ray

[Mark Wey]

Steve and Nancy:

It is easy to spend some one elses money.  :P But while you are at it. Check this out  www.e-marine-inc.com/products/gfopacking/packing.html
There will never be a better time for a drippless packing.

Mark

[APACHE]

Steve : You haven't mentioned how long you have scheduled to have your boat out of the water.?  Shafts and cuttless bearings can be purchased locally if you only are out of the water 2 or 3 days.

Why the length?  A drive shaft has a keyway cut into the the transmission flange end and you don't want more than 1 inch distance between the aft end of the strut and the forward hub of your prop.  So Catalina (or anyone else) needs the length of your old shaft so they can make you one of the proper length.  If I were home I could tell you the length that I ordered for my 1988 with a M25XP.  Let me know and you can hope that on your C34 that the engine, prop and strut will use the exact same length as mine.  Off the top of my head I'd guess that I ordered 59" length stainless shaft.  

[Mike Vaccaro]

Steve,

If you have a stock system, you might consider sticking with bronze for the shaft.  Yup, not as strong as stainless, and will wear a quicker; but much better from a dissimilar metal point of view.  If you end up with a stainless shaft, a bronze prop bolted to a hardened steel flange on an aluminum transmission housing running through a bronze cutlass, you're just building a better battery!

If your shaft is isolated from the transmission (i.e., some type of non-stock coupling that breaks the circuit), then stainless is fine.  It also might be required by some types of propellers (maxprop feathering type comes to mind).

One other consideration is replacing the stock coupling with a compression type.  This does away with the key in the shaft at the transmission end, and while it may seem counterintuitive, it's actually a better way to mount the shaft from an engineering standpoint since it does a better job of transmitting load.  One of the better couplings on the market that isolates the shaft electrically, provides good vibration damping and uses a compression fitting is the Bullflex type produced by Vetus.  The other advantage of this type is that you can simply trim the end of the shaft that mounts in the coupling.

Cheers,

Mike

[APACHE]

Steve : I'm home and pulled out my invoice from March 2000.  So much for my memory, as I shaft I ordered was  57" x 1" S.S.  316 @ $189.  
I'd still recommend that you pull YOUR shaft and use YOUR length measurement.
I also have a Vetus flexible coupling and like Mike strongly recommend it, IF you still have an M25XP engine - there's not enough room if you have a M35.  

[Philip Imhof]

I found myself in a position this summer to have to replace the prop shaft on out 1987 C34. Probably Catalina Yachts won't have the right length. They didn't have one for mine, and they suggested ordering it from a local machine shop. I would make prior arrangements with a machine shop to have it done. Then have the boat hauled, cut the shaft in two and remove it. Bring the shaft (both pieces) to the shop with the flange, and the prop. They can do the whole job in a few hours. When you drop it off, pick up the cutlas bearing and replace it while you're waiting for the shaft. There are instructions for removing/replacing the cutlass bearing and the shaft in our tech notes. I replaced the bearing in less than 30 minutes, the shaft took about an hour. Aligning the shaft with the engine took another hour. It was not as hard as it seemed.

[Stephen Butler]

First, many thanks for all the input...some good and reassuring advice!

The boat will be out of the water on the hard for 3 days.  After trying to speak with someone at Catalina, think we will purchase a new shaft and bearing locally (Ft. Lauderdale).  Will also locally purchase a new steaming light and mast boot.  As for ss316 vs bronze question, we will decide this a little later.  (I teach chemistry and have shamelessly assigned calculating the various electro-potentials and expected currents as an extra-credit problem.)

As for the packing...already have changed to the Telfon and think it great.

Again, our thanks for your advice...it has made a world of difference to these new C34 owners.

Steve and Nancy
Wildflecken II

[Stephen Butler]

Had an interesting conversation with Catalina Parts.  Now, Catalina only stocks 55" prop shafts. Shafts still come in ss or bronze.   Nothing longer or shorter.  Is this the new 'standard length' for all C34s?  By the way, Catalina Parts was exceptionally helpful.

[Ray & Sandy Erps]

Mike,

How does that compression coupling work?  Is it cone shaped with a recessed nut?

Steve,

One of your posts was signed Wildflecken II.  Does that refer to the army post in Germany?

[Stephen Butler]

Wildflecken is indeed the Army post in Germany.  My wife and I met and married there in 1970.  Wildflecken means 'wild place' and it gets a bit 'wild' when our C34 is offshore.

[Ron Hill]

Steve : Thinking back I did cut an inch off the the shaft before I installed it.  I also have a Vetus flexible coupling that can accommodate more varying length than the standard hard coupling.  That type (flexible) also lets you forget about future engine shaft alignment.
BTW, I was usually at Graffenwhor or Vielsak.
A thought.  

[Ray & Sandy Erps]

Small world.  I was stationed at Wildflecken for two years, 1979-1981.  My wife and I made our first home in a one room basement apartment in Oberbach.  Oma and Opa lived above us and their son and family lived in the third floor.  The son later became major (Burgermiester) of Wildflecken in the late 80's or early 90's.  We still exchange Christmas Cards with the Schrenk family.

Installing a flexible coupler is on my list of things to do. (barely back on topic)

[Stephen Butler]

Just heard from Kent at Catalina Yachts (great service!).  It seems that C34s built after #1230 have a 55 inch long prop shaft, while those with a lower number have a 57 inch long shaft. Naturally, we have a lower number hull, and Catalina only stocks the shorter shaft.  Oh well.

Kent suggest either having one fabricated at my site, or getting a coupler that provides an extra 2 inches and ordering a 55 incher from Catalina.  We will go with a local machine shop.  Also, Kent commented that there should be 1 inch clearance between the prop hub and the strut.  Interesting stuff.

Anyway, thanks to all for the info and to Kent for the fast response.