Catalina 34

General Activities => Main Message Board => Topic started by: Stephen Butler on October 13, 2004, 03:23:58 PM

Title: Prop Shaft Replacement
Post by: Stephen Butler on October 13, 2004, 03:23:58 PM
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
Title: Prop Shaft Replacement
Post by: Stu Jackson on October 13, 2004, 03:56:27 PM
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.
Title: Prop Shaft Replacement
Post by: rirvine on October 13, 2004, 05:09:02 PM
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
Title: Prop Shaft Replacement
Post by: Mark Wey on October 13, 2004, 05:50:59 PM
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
Title: Prop Shaft Replacement
Post by: APACHE on October 13, 2004, 06:52:36 PM
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.   :wink:
Title: Prop Shaft Replacement
Post by: Mike Vaccaro on October 16, 2004, 06:39:05 AM
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
Title: Prop Shaft Replacement
Post by: APACHE on October 16, 2004, 01:56:20 PM
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.  :wink:
Title: Prop Shaft
Post by: Philip Imhof on October 16, 2004, 07:26:25 PM
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.
Title: Prop Shaft Replacement
Post by: Stephen Butler on October 17, 2004, 09:23:54 AM
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
Title: Prop Shaft Replacement
Post by: Stephen Butler on December 10, 2004, 07:14:05 AM
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.
Title: Prop Shaft Replacement
Post by: Ray & Sandy Erps on December 10, 2004, 02:10:35 PM
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?
Title: Prop Shaft Replacement
Post by: Stephen Butler on December 10, 2004, 02:41:56 PM
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.
Title: Prop Shaft Replacement
Post by: Ron Hill on December 10, 2004, 06:39:07 PM
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.   :wink:
Title: Prop Shaft Replacement
Post by: Ray & Sandy Erps on December 10, 2004, 08:01:47 PM
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)
Title: Prop Shaft Replacement
Post by: Stephen Butler on December 15, 2004, 09:40:57 AM
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.
Title: Prop Shaft Replacement
Post by: Ron Hill on December 15, 2004, 06:25:32 PM
Steve : I've done some thinking and believe that I figured out the shaft length problem.  
The older C34's have a M25/M25XP engine which has 3 cylinders.  The later boats have an M35 engine with 4 cylinders and is one cylinder longer than the M25 engine.  So the M25 engine needs a longer 58/59" shaft as opposed to the 55" shaft for the M35 engine.

I just talked to Gerry Douglas and appraised him of the problem.  He said that Catalina makes their own shafts so it shouldn't make any difference.  I told him the info that his parts dept was putting out and asked if he would look into the shaft length problem.  He said he would.  
I also mentioned that beside the 1000+ C34 that need the longer shaft that 1000+ C36's were probably in the same predicament. :wink:
Title: Prop Shaft Replacement
Post by: Stephen Butler on December 16, 2004, 05:58:46 PM
Ron: Appreciate the technical followup!  I have gone back to Kent at Catalina for specs for the prop shaft on our boat and the OD of the cutlass bearing.  If I can get these from Catalina, I can have a new shaft and bearing waiting for us at the boat when we arrive on the 20th of December.  About the reason for the different prop shaft lengths...you are exactly correct...checked the difference between the block lengths of our M25XP and the M30 series and the missing inches are there!  Another interesting comment from our potential supplier in Ft. Lauderdale (F & J Prop Shop); they still quote a lot of bronze, and stock it, but have not sold one for almost 20 years....not much cost difference from the ss and the ss has much better corrosion resistence.

So, now waiting to hear from Kent for the prop and bearing specs.  Would certainly have preferred to purchase from Catalina, but think we are now out of time.  Oh well, another time.  Thanks again.
Title: Prop Shaft Replacement
Post by: Mike Vaccaro on December 18, 2004, 06:47:09 AM
"Common wisdom" dictates that stainless steel is a better shaft material than silicone bronze.  From a stress and capabilities point, it is, but that is largely irrelevant for the small, low-load application such as the prop shaft in the Catalina 34.  From a corrosion-resistant standpoint, silicone bronze is the better material.  While it will wear faster than stainless, it is a more robust material under the water.  While there is sufficient oxygen in water to form a protective layer of oxidation on 300-series stainless, there is also sufficient chloride to attack it.  Also, the more dissimilar metals mixed under the water, the better the battery--especially true in salt water.  In a "perfect" installation, the shaft, prop, bearings and strut are all made from the same material and electrically isolated from the gear box.  From a corrosion standpoint, bronze is a better choice, if it structurally adequate.

Realistically, it doesn't make much difference, but in all cases it's critical that the zincs be properly installed and maintained below the waterline.  The degradation of the zinc will be accelerated if dissimilar metals are present (e.g., a stainless shaft attached to a bronze prop), or there is a problem with electrolysis (usually caused by a fault with AC dock power if the boat is not equipped with a galvanic isolator [good] or isolation transformer [best]).  If a stainless shaft is used, it needs regular inspection to check for corrosion.

Cheers,

Mike