Catalina 34

General Activities => Main Message Board => Topic started by: Mike McDonald on January 06, 2017, 10:44:22 AM

Title: Prop shaft locking nuts
Post by: Mike McDonald on January 06, 2017, 10:44:22 AM
Does anyone know where to purchase the locking nuts at the end of the prop shaft, aft of the prop. I only have one nut and a cotter pin. I believe I have the thicker of the two nuts. I know it is a 1" shaft, but don't know the nut/thread size, or where to find them. I don't see them on Catalina Direct.
Mike.....
Title: Re: Prop shaft locking nuts
Post by: Ron Hill on January 06, 2017, 01:27:19 PM
Mike : Contact any prop shop or prop company and ask them for a replacement nut for a 1" shaft - it's standard. 

We ( also a C36 & C30 & C28)  all only have one castellated nut for a cotter pin - that's normal.  The only place on that prop shaft that has a second locking nut is at the stuffing box. 
With a castellated nut and cotter pin there is no need for a jam/locking 2nd nut.

A few thoughts
Title: Re: Prop shaft locking nuts
Post by: Jim Hardesty on January 07, 2017, 06:05:58 AM
Just to add my 2 cents.  The nut and cotter pin should be similar material to the shaft.
Jim
Title: Re: Prop shaft locking nuts
Post by: patrice on January 07, 2017, 06:53:58 AM
Hi,
There are 2 type thread per diameter.  Coarse or fine thread.
But as mention, if you have a nut with a pin, you don't need a jam nut (2nd nut).
Title: Re: Prop shaft locking nuts
Post by: Jim Hardesty on January 07, 2017, 08:49:50 AM
The normal thread size is 3/4 * 10.  FWIW  If you use 2 nuts the thin nut goes first, to full torque.  The thicker nut goes last, again to full torque.  That's by the book.  A lot of mechanics will do it the other way and don't seem to have problems.

Jim
Title: Re: Prop shaft locking nuts
Post by: Craig Illman on January 07, 2017, 11:23:30 AM
If you're going to start getting technical, http://www.pbase.com/mainecruising/fitting_a_prop
Title: Re: Prop shaft locking nuts
Post by: KWKloeber on January 07, 2017, 10:20:17 PM
Quote
If you're going to start getting technical............

For some information overload ........  here's WHY the jam nut should be used first, followed by the thick nut..
http://www.boltscience.com/pages/twonuts.htm

-kk
Title: Re: Prop shaft locking nuts
Post by: Ekutney on January 08, 2017, 12:04:42 PM
The following is a picture of the setup of the propeller on my C34, the PO says this is the way it has been for over 27 years.
Title: Re: Prop shaft locking nuts
Post by: Mike McDonald on January 08, 2017, 12:30:39 PM
Thanks to everyone for the great feedback, I really appreciate it. I hope to get out to the boat this week to check the stands, so I'll double check my shaft nut configuration. I thought I had taken some photos in the fall, but can't seem to find them. Thanks again!
Mike.....
Title: Re: Prop shaft locking nuts
Post by: Noah on January 08, 2017, 02:44:57 PM
Ed- We're the two zinc shaft collars also the PO's way of doing things?
Title: Re: Prop shaft locking nuts
Post by: Ekutney on January 08, 2017, 04:28:22 PM
Noah,

It originally had two zincs on the shaft so when I replaced them I did the same, I asked the yard where the boat was hauled and some others at local Marine supply, what I got what it might be overkill but wouldn't hurt.  I searched for info on this forum & found nothing negative.  Why do you ask?

BTW, when I had the boat hauled for the survey I was told the nuts were backwards, as was stated on this forum the small nut should got on first.  I forgot to reverse them when the boat was hauled, had it written down but it was overlooked because other items took priority.
Title: Re: Prop shaft locking nuts
Post by: Noah on January 08, 2017, 05:39:17 PM
Ed- i have just never seen two zincs on the shaft at once. I don't know if it is "wrong"... Just curious. It may be a "fine" belt and suspenders approach?
Title: Re: Prop shaft locking nuts
Post by: Ron Hill on January 09, 2017, 02:54:23 PM
Noah : Most people that attach 2 shaft Zns do it to prevent one Zn from eroding at the thin thru bolt hole collors and falling off the shaft.   
That way there would be at least one Zn.  I have never done that.

A thought
Title: Re: Prop shaft locking nuts
Post by: Ekutney on January 09, 2017, 04:54:38 PM
At least somebody else has heard using 2 Zncs on the shaft, I feel better.  Thanks Ron.
Title: Re: Prop shaft locking nuts
Post by: patrice on January 10, 2017, 05:56:24 AM
Hi,

I also have 2 of them.
simple reason, when I got the boat, the zinc was halfway gone, so before splashing, I added a new one beside it, not knowing how long it would last.
So every spring I check the erosion of them, and when the older one get to eroded, I replace it.  Is it overkill, yes.
Title: Re: Prop shaft locking nuts
Post by: mainesail on January 10, 2017, 09:17:27 AM
The shaft anodes on a sailboat should be placed as close to the strut as possible without impeding flow of water to the cutlass bearing. Usually about two finger widths in front of the strut is fine. Placing them further away from the strut creates shaft imbalances and "shaft whip" (jump rope effect) when the anodes wear unevenly.

Also most anodes are not installed properly to allow them to do their job...

Anode Installation - Best Practices (http://forums.sailboatowners.com/index.php?threads/anode-installation-best-practices.175835/)

Title: Re: Prop shaft locking nuts
Post by: Bill Shreeves on January 18, 2017, 08:00:48 PM
Mainesail, once again, great info on the anode install best practices!