[C320-list] Stainless vs bronze with folding prop

[Jeff Hare]

Hi Jeff,

If your bronze shaft is straight *and* your new prop isn't overpitched too
much *and* your engine-coupling-shaft alignment is good *and* your cutlass
bearing is in good shape with very minimal play, you'll be fine with a
bronze shaft.  If the cutlass bearing is sloppy or you have some
mis-alignment then a bronze shaft could develop some shaft whip when
motoring hard or in bumpy seas.

That said, when you haul out in the future and think it's time to change the
cutlass bearing do yourself a favor and just pop in a stainless prop shaft.
They're only a couple hundred bucks and reduces the whip induced vibration
quite a lot.  It's really not the weight of the prop that's at issue here,
but how much the prop tends to torque to one side when pulling hard, and the
characteristics of the prop probably determine this more than weight.

We replaced our bronze shaft with a SS from DeepBlueYachtSupply.com and it
took about 4 hours on a Saturday.  Used the association's cutlass bearing
tool to replace that at the same time and the total job was a snap with a
helper.

My $.02

-Jeff

-----Original Message-----
From: c320-list-bounces at lists.catalina320.com
[mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Jeffrey Brown
Sent: Thursday, October 03, 2013 7:19 PM
To: Catalina C320 List List
Subject: [C320-list] Stainless vs bronze with folding prop

So I'm getting mixed advice from Martec. I bought a new folding prop and
when my diver went to install it he said I need to get a stainless shaft and
he highly recommends not to install it on my bronze shaft.  Gary at Martec
told me when I bought it is was not an issue. I recall when I posted about
it before I bought it there was some chatter about this. I'm wondering if
anyone has a Martec folding prop on a bronze shaft and if they have had any
issues. My boat is hull 75 or something, 1994. 

Jeff Brown
949-350-5123