[Public-list] bronze rudder post replacement
John Birch
Sunstone at cogeco.ca
Tue Oct 17 22:07:57 PDT 2006
Try to get silicon bronze, easier said than done - there is a lot of stuff
out there called bronze which is closer to brass ... some "bronze" even has
zinc in it - you don't want that. Also I would suggest you want forged,
rolled or extruded bronze not cast - plain castings are not nearly as
strong.
Same with bolts and screws - silicon bronze. A "great deal" usually isn't,
its often crap bronze - use a reputable specialist supplier - up here I go
to Pacific Fasteners off Chauncey Drive off Islington in Toronto.
Just a suggestion
Cheers,
John
----- Original Message -----
From: <brooks.glenn at comcast.net>
To: "Alberg 30 Public List -- open to all" <public-list at alberg30.org>;
"Alberg 30 Public List -- open to all" <public-list at alberg30.org>
Sent: Tuesday, October 17, 2006 11:51 PM
Subject: Re: [Public-list] bronze rudder post replacement
> Hello Chris,
>
> I would definitely replace with bronze, except probably all the metal in
> the rudder should be replaced bronze. I just took my 30 yr old bronze
> shafts ( and rudder from which they recently were attached) to a
> commercial boat yard/machine shop. The shop owner said his experience is
> that short gudeon shafts are very common on sailboats, particularly if
> located just below the prop aperture, ala A-30's... Two small pins run
> into the rudder centerline are all that are needed to hold the shaft from
> turning. B
> ronze shaft material is commonly available in many sizes. Any good
> machine shop could turn the grudens/(pintels??) out of bronze stock, +
> there are several foundries on the internet who sell cast pieces...
>
> Here's what I discovered when I removed both upper and lower shafts, plus
> the 6" mid rudder grudeon shaft... Found out
> the upper shaft runs from the tiller assembly, down through the stop water
> in the hull, then down the leading edge of the rudder, then bends rearward
> around the inside of the prop aperture to about 2/3d's of the way to the
> bottom leading edge of the rudder. The shaft sort of zig zags ( picture
> half a carton ligthing bolt)to get around the back side of the prop
> aperture, and runs behind the grudeon shaft about 4-5 inches. The machine
> shop guy says this design gives terrific additional strength and tranmits
> a great deal of torque down through the rudder, Thus helping prevent the
> shaft from twisting in the F/G and foam rudder body.
>
> I am goling to have the shop extend the new shaft anothor 18" or so down
> to the bottom of the rudder- replacaing the origianl 8" lower stock wikth
> this all new, full length piece. I cut through about 4 ea 5/16" pins
> bedded laterally through the rudder center line and seated in the shaft
> itself. The pins also stop the shaft from torquing out of position.
> Will put 4 or 5 pins through the new full length shaftin to the rudder
> body to prevent twist.
>
> My existing upper and lower shaft is 1" bronze. Gudeon shaft origanlly
> 3/4" bronze, but now 5/8 and crumbling rapidly, with 2 1/2" 5/16th bronze
> pins holding it from twisting.
>
> Bronze shaft stock is still commonly available, so I am going to stay with
> all bronze shafts. I wouldn't worry about casting the gudeon shaft. you
> should be able to buy a piece of 3/4, 7/8 1", 1/18 and up, as you need.
>
> Also am thinking about having the shop make up a second set of
> gudeon/pintels ( still havent figured out which is which), ie to add an
> additional pivotpoint/support either at the top of the shaft just below
> where the fairing leads into the full or above the rudder shoe... this
> is probably overkill, but am going to Hawaii and Alaska in next couple of
> years, so its just extra small insurance.
>
> BTW, the easiest way I found to cut out the FG material around the shaft
> was to use a thin, high speed composite metal cutting wheel on my 4"
> grinder. This cut a nice clean, vertical 3/16 slot through the FG layers,
> just like butter. Then hung up a bit on the shaft material, making a nice
> depth gauge for cleaning out just enough material to chisel out a channel
> where the shaft was embedded in the original mold.
>
> I will grind out the top half of the rudder and reglass and pin everything
> back into place once the shop returns my proud and shiny, NEW full length
> bronze shaft assembly, and I fit it into the existing channel.
>
>
> Also, I intend to have them machine a 5/8 or possibly 3/4" pin directly
> out on the end of the new full length shaft assembly, and ream out the
> rudder shoe to accept the new pin dimension. Will give lots more strength
> and longer life. Also might go with 1 1/8th" stock instead of existing
> 1", and have then turn the top part down to 1" to fit the packing gland in
> the full. Again, small difference, but a lot of added strength and larger
> pin size for the next 30 years wear and tear.
>
> I spent a lot of time very tentatively cutting into the rudder to remove
> the two lower pieces-- maybe 4 hours. Once the shape of the upper took
> form, it went quicker. Now I wouldn't hesitate to whack the thing right
> from the beginning, top to bottom in an hour or two, if I had to. Which I
> won't , because in 30 years the boat will be 60 years old and I'll be 90,
> so probably will just sell it and buy another which already has the work
> done.
>
> So, probably more info than you wanted to know, but it wasn't nearly the
> fema disaster I was expecting. Iam very confident ( now) the whole thing
> will go back together in short order, probably by end of the week, except
> for curing time...
>
> PS. George, thanks Very Much for the followup info you sent. Very
> helpfull anticipating how to do this thing!
>
> Glenn
> Dolce #318
>
>
> -------------- Original message ----------------------
> From: "Chris Blain" <chris.blain at gmail.com>
>> I have another question regarding this whole assembly- the mid rudder
>> strap/gudeon - has anyone fabricated one from bronze strip, or is there a
>> source for a cast one? My boat (an A35, but identical in rudder
>> contruction,
>> had a stainless strap which showed classical corrosion patterns and was
>> almost gone, and I'd prefer to replace it with less prone to corrosion -
>> bronze.
>>
>> Thanks,
>> Chris
>>
>>
>> On 10/17/06, brooks.glenn at comcast.net <brooks.glenn at comcast.net> wrote:
>> >
>> > Hi George,
>> >
>> > I would like to ask an additional question regarding your rudder stock,
>> > if
>> > I may?
>> >
>> > Is your lower rudder shaft all one piece or two short pieces?
>> >
>> > I just opened up my lower rudder and found two short pieces 6-8" long:
>> > one
>> > at the bottom with the pin fitting into rudder shoe, the other at
>> > mid-rudder
>> > where it can be grabbed by the pintel/grudgeon assembly...Both have two
>> > 5/16" round pins several inches long bored into the rudder to keep
>> > everything from spinning. The design seems a little light weight for
>> > off
>> > shore sailing...( but it has lasted 30 years now...)??
>> >
>> > Do you have any thoughts about replacing these two short ones with one
>> > long shaft- aside from cost?
>> >
>> > Thanks much,
>> >
>> > Glenn
>> > dolce #318
>> > -------------- Original message ----------------------
>> > From: George Dinwiddie <gdinwiddie at alberg30.org>
>> > > brooks.glenn at comcast.net wrote:
>> > > [snip]
>> > > > Can anyone suggest the best way to do this?
>> > >
>> > > I don't know if it's best, but my approach is included in the
>> > > Maintenance Manual. Basically I chiseled out the foam and removed
>> > > the
>> > > lower post, which was in a condition similar to yours. I had it cut
>> > > off, drilled and tapped. I then put it back in the rudder with glass
>> > > and epoxy and filled the voids with thickened epoxy.
>> > >
>> > > > PS, I really don't want to go stainless as the pintels and shoe
>> > > > are
>> > > > in excellent condition, and the rudder post mounted in the hull is
>> > > > bronze.
>> > >
>> > > You really don't want to use stainless below the waterline. See
>> > > http://alberg30.org/maintenance/Steering/CreviceCorrosion/
>> > >
>> > > --
>> >
>> > > ----------------------------------------------------------------------
>> > > When I remember bygone days George
>> > > Dinwiddie
>> > > I think how evening follows morn;
>> > > gdinwiddie at alberg30.org
>> > > So many I loved were not yet dead,
>> > > http://www.Alberg30.org
>> > > So many I love were not yet born.
>> > > 'The Middle' by Ogden Nash
>> >
>> > > ----------------------------------------------------------------------
>> > >
>> > >
>> > >
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