[C320-list] coupler re-install

[Irving Grunes]

I seem to remember putting a zinc or collar of some sort just forward of
the packing nut in case the key shears or the set screws let go, the the
shaft would not fall backwards into the rudder.

Irv Grunes
Former #851.


On Sat, Apr 25, 2015 at 12:46 PM, Rick Sulewski <rsulewski at bex.net> wrote:

> Ted,
> I found that installing the coupler as you suggest works while being
> certain
> to line up the coupler set screw holes with the shaft dimples and then
> installing the set screws followed by taping in the key. That arrangement
> worked better in my situation when I recently removed the coupler to
> replace
> an aging 20 year old shaft log hose. I initially attempted to install the
> coupler by installing the key in the shaft and then driving the shaft into
> the coupler when that prop shaft coupler was attached to the engine side
> coupler, using piece of wood to prevent damage to the shaft threads with
> the
> prop installed, but that approach did not work for my. The boat, while in
> its cradle, naturally experiences a degree of hull flex and the shaft could
> not be driven all of the way into the coupler even with a large degree of
> tapping force at the prop end of the shaft because the shaft did not
> totally
> line up when it was half way into the coupler. Further movement was being
> held back by a portion of the leading edge of the shaft resisting against
> the coupler due to the degree of  hull flex, creating misalignment while
> resting in the cradle (causing increasing amounts of excessive force
> necessary to continue to drive the shaft into the shaft side coupler which
> I
> opted not to continue). I then had to remove the partially installed shaft
> from the coupler with the flange puller and reinstall the coupler by
> driving
> in the key from the engine side after being certain the coupler set screws
> were seated into the dimpled shaft in order to line up the key slots on the
> back side of the shaft & coupler. After tapping in the key more than
> halfway
> in,  I met with some resistance and then reinstalled the shaft side coupler
> to the engine side coupler and then only had to tap  the end of the prop
> shaft to further drive the key into the last portion of the coupler,
> followed by separating the coupler for additional taps on the key leaving
> the key almost flush with the face of inside edge of the coupler.
>
>  It is important to understand that the coupler should be tightly fit on
> the
> shaft and the key helps to not only keep the shaft from rotating within the
> coupler, but also serves in my case to fit very snugly between the shaft &
> coupler. If the shaft to coupler fit is too loose, then the shaft could
> work
> loose (wobble) within the coupler and that could result in the shaft
> separating from the coupler if the shaft side of the set screws shear off
> when operating suddenly in reverse or under strong power in reverse. That
> is
> why it is not advisable to grease or lubricate the shaft when reinstalling
> the shaft in the coupler because the rust that naturally develops between
> the shaft and coupler serves to also provide a tighter tolerance over time
> between the shaft and coupler. Do not forget to tightly wired the set
> screws
> to prevent them from working loose.
>
> As an additional precaution it is advisable to have your prop zinc located
> securely just ahead of your prop strut by a length not greater than exists
> between the coupler and packing log nut in the event the prop shaft may
> ever
> separate from its coupler with the intent of relying on the shaft zinc to
> (hopefully) keep the shaft from totally exiting/departing beyond the
> packing
> log nut and creating a large flow of water to overwhelm the bilge pump.
>
> Hope this reply is clear. If not, feel free to contact me off line at my
> email address.
> Rick 95 320 hull #277
>
> -----Original Message-----
> From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
> Of tharrison at innovations-plus.com
> Sent: Saturday, April 25, 2015 10:45 AM
> To: C320-List at Catalina320.com
> Subject: [C320-list] coupler re-install
>
> Do you put the coupler on the shaft first and then tap the key in with a
> hammer?
>
>
>
>
>
>
>
> Ted Hull 424
>
>
>