prop zinc

[sweetwater]

Hello again...love the fall maintenance!! I remember someone on this site installing a Prop nut zinc instead of a shaft zinc. I ordered mine from Defender and was looking through the search feature for pictures of the installation. I have seen our props installed with the big nut against the prop, then the small nut and cotter pin. I have also seen the small nut first then big then pin. When installing this zinc anode, I would THINK I would install: Prop-big nut-new Zinc nut-cotter pin. Anyone with info? Thanks fellas

[Pitou]

Right or wrong ... depends upon who is asked. I've had mechanics tell me that no cotter pin is necessary if you use a 2nd "lock nut". I like still like the idea of a cotter pin.

I have the "F" sized Prop Nut and first put on the regular heavy nut and then screw the prop nut snug upon the regular nut lining up the slots on the prop nut with the cotter pin hole in the shaft using, for both, a long handled pipe wrench with a piece of pipe for leverage. The prop nut anode just slides on and is secured by the provided star washer & bolt.

I've found that as the anode wears the bolt no longer is tight against it and eventually backs off allowing the anode to drop. I now apply "red" loctite to the bolt to prevent that issue. I know "red is permanent", but the saltwater must do something that allows the bolt to be removed fairly easily at change out.

[RobS]

I've found that as the anode wears the bolt no longer is tight against it and eventually backs off allowing the anode to drop...

This always concerned me.
Especially that it's spinning a couple thou rpm's.
If you have room on the shaft (as we 28TE owners do) why not just stay with the proven collar zinc?

[Pitou]

I've found that as the anode wears the bolt no longer is tight against it and eventually backs off allowing the anode to drop...

This always concerned me.
Especially that it's spinning a couple thou rpm's.
If you have room on the shaft (as we 28TE owners do) why not just stay with the proven collar zinc?

I agree Rob ... if you have room for a collar zinc, that is the way to go and not bother with the prop nut.

With the Cummins 370 ... no such room and the prop nut is the only option. The Yanmar 300/315 gives you the 28TE owners plenty of room for the collar zinc. I'm not sure what Sweetwater is running.

[jleonard]

On my previous boat I had no room for a collar zinc unless I cut it down, so then I treid the prop zinc.
Didn't like that so I eventually had a 1 inch thick solid steel spacer made for between the tranny and pop shaft couplings. That moved the shaft back (you guessed right, 1 inch) and gave me plenty of room for my collar zinc.
So if you have room to move the prop aft, this is a good option. This also gave me room for a set of spurs.
Here is a pic of that setup. Zinc is not in the pic now as this was taken after fall haulout one year.

fairing (750 x 562).jpg

[RobS]

With the Cummins 370 ... no such room and the prop nut is the only option.

Interesting. So it sounds like the Cummins/ZF combination of different physical dimensions than the Yanmar/ZF setup must end up putting your shaft coupler slightly forward, hence the tail of the shaft ends up slightly shorter.

From the endless collection of Albin pics on my file server I pulled these from a 2001 Cummins 370 28TE that I had looked at and it has a collar zinc. And this is the larger egg zinc, not the narrower collar or donut style.

Click on the first picture - If you look at the front edge of his shaft zinc you can see it is quite shiny with a groove in it. No doubt there is slight forward movement of the powertrain (especially on hard acceleration) which is pushing that shaft zinc up against the cutlass bearing housing.

However, it does appear that a collar or donut style shaft zinc would fit with adequate clearance.

Kevin, is your clearance not as pictured?

[Pitou]

That's my power plant in your photo Rob. The shaft in your other photo seems further back than mine / I have maybe 1 1/2 inches tops. J's idea of an extension has the brain turning ...

here are some photos I took last spring during the strip & barrier coat process :

CIMG0060 (480x640).jpg

CIMG0061 (640x480).jpg

[jleonard]

note anode wear after 1 season

Mine have always been shot after a season. Sometimes I have had to change them out in August.

[sweetwater]

Thanks guys, I just remember reading threads about people having a hard time fitting the collar zincs on their boat, and I ordered my prop nut while still in the water, so I couldnt measure mine. My old boat had a Bravo 3 with a prop nut and it seemed to work well so I went with that. I also liked the idea of that heavy chunk of metal being downstream of the prop if it fell off as opposed to the collar zinc being upstream. Pitou... do the 55 extra hp make a big difference in performance with your boat over us Yanmar commoners? Looks like a nice set-up.

[Pitou]

Pitou... do the 55 extra hp make a big difference in performance with your boat over us Yanmar commoners? Looks like a nice set-up.

I think it tends to help out a little when carrying x-tra ice & beer!

[RobS]

J's idea of an extension has the brain turning ...

No can do on our reverse tranny setups, a spacer would only shorten the shaft