Prop shaft locking nuts

Mike McDonald · 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.....

Ron Hill · 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

Jim Hardesty · 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

patrice · 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).

Jim Hardesty · 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

Craig Illman · January 07, 2017, 11:23:30 AM

If you're going to start getting technical, http://www.pbase.com/mainecruising/fitting_a_prop

KWKloeber · 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

Ekutney · 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.

Mike McDonald · 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.....

Noah · January 08, 2017, 02:44:57 PM

Ed- We're the two zinc shaft collars also the PO's way of doing things?

Ekutney · 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.

Noah · 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?

Ron Hill · 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

Ekutney · January 09, 2017, 04:54:38 PM

At least somebody else has heard using 2 Zncs on the shaft, I feel better. Thanks Ron.

patrice · 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.