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

Tue Sep 12 06:50:10 PDT 2006

Jon,
In the information that I got from the PO I found an envelope with the SN of our H5BB on the outside, a letter from Steve Armatage and a couple pages on how to maintain the prop, including how to adjust the bearings (tourque down to 14 ft lbs or 18 NM and then back of 1/4 turn).  The most dificulty I had was tightening the lock nut with out it adjusting the tension on the bearings.

I would be happy to make a copy and send to you if that would help.
Bruce
Somerset 671 SoCal
Sent via BlackBerry from Cingular Wireless  

-----Original Message-----
From: jonvez at comcast.net
Date: Tue, 12 Sep 2006 13:09:28 
To:C320-List <c320-list at catalina320.org>
Subject: Re: [C320-list] Blade falls off of Autoprop propeller!

Larry,

Did the procedure you mention from AP come with the propeller? I don't believe I received the procedure you are referring to...

Regards,

Jon Vez

-------------- Original message -------------- 
From: "WindSwept" <c320_windswept at sbcglobal.net> 

> 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: 
> To: "C320-List" 
> 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" 
> > Date: Sat, 9 Sep 2006 09:41:36 
> > To:"C320-List" 
> > 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" 
> > To: "'C320-List'" 
> > 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 
> > 
> > 
> > 
> 
> 
> 