[C320-list] Blade falls off of Autoprop propeller!

[WindSwept]

Bruce,

I'll respond here to a couple of things.

You took a hit on the 240 Buicks so I won't comment on that.  The correct 
unit on the torque is 14 ft-lbs or 18 NM per the instructions I received. 
My torque wrench is calibrated in inch pounds and NM.  14 ft pounds is 168 
inch-pounds.  Any of the three will work.

The website doesn't really talk about bearing adjustment.  It really just 
adresses cleaning out of the bearings.

This weekend I checked the bearing adjustment and followed the AB Marine 
procedure where you back off the retaining cap by 1/4 turn.  I also have the 
procedure recommended by Steve, but decided to go with the procedure 
provided by the designers and manufacturers over the distributor.  I have no 
reason to believe that Steve's procedure wouldn't be perfectly fine and it 
is easier to follow.

When the bearings are adjusted using the procedure provided by the designers 
of the autoprop, the blades spin smoothly and there is just a small amount 
of play in the bearings.

Larry
----- Original Message ----- 
From: <bruceheyman at cox.net>
To: "C320-List" <c320-list at catalina320.com>
Sent: Saturday, September 09, 2006 6:44 PM
Subject: Re: [C320-list] Blade falls off of Autoprop propeller!


> Larry,
> Sorry you lost the blade! I'd be very interested in how freely the blades 
> rotate when you get your prop back from the factory.  I just rebuilt ours 
> but on the direction of Steve Armitage I did NOT follow the original 
> instructions.  The original instructions call for you to tourque down on 
> the adjustments for each blade to 14 nm (I know I have the number right 
> but not sure about the units) and then back off 1/4 turn.  Steve told me 
> to just tighten them down until there was no play in any direction and the 
> blades still rotate freely.  The rebuild kit was about 240 buicks and 
> fairly easy to do. Hardest part was getting everything good and clean. I 
> also have the H5BB so no grease.
> Bruce
> Somerset 671 SoCal
> Sent via BlackBerry from Cingular Wireless
>
> -----Original Message-----
> From: "Robert E. Sloat" <resloat at comcast.net>
> Date: Sat, 9 Sep 2006 09:41:36
> To:"C320-List" <c320-list at catalina320.com>
> Subject: Re: [C320-list] Blade falls off of Autoprop propeller!
>
> Check out their website at http://ab-marine.com/.  There is all kind of
> installation information and
> maintenance procedures for the various model Autoprop propellers.  Mine is
> the H5 model which does not require any greasing.  For the models which
> require greasing, they suggest every 2 years.  The installation 
> instructions
> for my prop suggest rotating the blades at haul out to make sure they 
> freely
> move and gives information on bearing replacement kits when needed.
>
>
>
> ----- Original Message ----- 
> From: "WindSwept" <c320_windswept at sbcglobal.net>
> To: "'C320-List'" <C320-List at catalina320.com>
> Sent: Saturday, September 09, 2006 8:59 AM
> Subject: [C320-list] Blade falls off of Autoprop propeller!
>
>
> A funny thing happened on the way to the ship yard this spring for my
> semi-annual bottom job.  Well maybe not so funny.
>
> Carla and I spent the night at anchor in a cove about 1/2 mile from the 
> yard
> the prior to dropping off WindSwept.
>
> After hauling anchor when we tried to motor over to the yard the boat 
> shook
> terribly at any RPMs above idle.
>
> We quickly anchored again and I dove below the boat to find out what was
> wrapped around the prop, but was amazed to find that one of the three 
> blades
> of my Autoprop was just......missing!
>
> We managed to sail to the yard which is located up a narrow channel and 
> moor
> in the haul up slip.  Luckily the wind was from a favorable direction.
>
> To make a long story shorter, I had the fixed three blade that came with
> WindSwept reinstalled and sent the Autoprop to AB Marine for analysis and
> repair.  The prop had to be sent back to the factory in the UK so the
> engineers could look at it and a new blade could be fabricated.
>
> The reason for the failure was that the bearings were excessively worn
> causing too much torque to be applied on the mechanical fastenings that 
> hold
> the blades on.
>
> At this point I think it is relevant to mention that I had purchased the
> Autoprop used about 7-8 years ago from a 320 owner who had traded up.  I 
> do
> not believe I received all the paperwork that one would normally receive
> with a new Autoprop.  This paperwork discusses the need to inspect and
> adjust the bearings at each haulout.  AB Marine sells a kit for this
> purpose.
>
> I was upset with AB Marine as through the years I have had many 
> discussions
> on this subject and even though I asked about maintenance, this was never
> mentioned.  In their defense, they probably thought I had the original
> instruction sheets for installation and maintenance.  As an engineer I was
> amazed that I didn't need to do any maintenance on a bearing in this type 
> of
> service.  The autoprop had been on WindSwept for four years without
> maintenance before the failure occurred.
>
> The point of all this is that I think this was a preventable situation had 
> I
> know to inspect the bearings for excessive looseness and adjust every year
> or two as needed.
>
> I plan on having the Autoprop put back on in a couple of weeks as I can
> definitely say it really improves boat speed and handling in all 
> situations.
> I will inspect it annually and disassemble and adjust bearing clearances
> every other year at a minimum.
>
> I wanted to share my experience with others in the hopes that you don't
> experience the same problem.  In another situation it could have been much
> more disastrous.
>
> Larry
> WindSwept C320 #246
>
>
>