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Thread: Need a rudder?

  1. #16
    Join Date
    Sep 2001
    Location
    San Rafael, CA
    Posts
    3,549

    Apropos

    Littlgull nee Sun Quest came to me with a stainless steel rudder

    shaft. It reacted with the rudder shoe, turning bronze into anode.

    Ate it up. This apparent reversal of the norm is recorded by others.


    My opinion is, and I did have a conversation with Roger Winiarsky,

    that Bristol supplied the bronze to Pearson when they were building

    Ariels and Commanders. HE SAID they supplied manganese bronze

    for the rudders, shaft and rod. Manganese bronze cannot be used

    under water.

    Cannot live under water. There may be stainless steel that can live

    under water, but it's too expensive. 316 cannot live under water.

    And in live marinas reacts with any other metal, especially bronze.


    From the existing, page 170

    "NOTES:" column: #4.. UPPER & LOWER RUDDER STOCK MADE OF

    NAVAL BRONZE. Naval bronze is naval brass, composed of 60%

    copper, 39.2% zinc, 0.75% tin (to make it "corrosion resistant".) It's

    a self-distruct battery, worse than manganese bronze in salt water.


    Concept uses the original rudder drawing from the Association Manual,

    with the two piece shaft to recreate the original rudder. Makes small

    logical changes for a simpler stronger non-welded unit, and individual

    DIY input. Uses all Everdur 655 silicon bronze. Under water bronze:

    97% copper, 3% silicon, 0.9% manganese. Bet, it never corrodes at

    the waterline inside the A/C rudder tube !!


    After 53 years, you want a new rudder.

    It's not hard if you DON'T follow exactly how they first did it.

    Machine shop can do all the hard work on the shaft.

    Found my old notes. Make copies and send you some?
    .
    .
    .
    .
    Last edited by ebb; 07-31-2018 at 03:36 PM.

  2. #17
    Join Date
    Sep 2001
    Location
    Santa Cruz, California
    Posts
    447
    Actually, I hauled my Ariel for routine hull maintenance and installation of a new transducer in July. The hull is in excellent shape. Regarding the rudder, the presenting problem was the rudder blade, which was apparently adversely affected by placing a zinc connected to an upper shaft bolt on the mahogany rudder. The rudder looked OK with the exception of some vertical cracks in the paint when first hauled, but as the rudder blade dried, the wood in the vicinity of the zinc split open revealing significant erosion of the wood. I installed the zinc with the intent of protecting the upper shaft after I inspected the rudder shaft some time ago. With the exception of an area about six inches around the zinc, the 53 year-old rudder blade is in excellent condition. While considering replacement of a section to the rudder or otherwise repairing it, we looked into the condition of the 53 year-old bronze rudder shaft.

    The shaft at the the top the rudder is pink in part and there is significant loss of bronze in the immediate area of the topmost rudder bolt. This is the location where one would expect the shaft to break. If anyone has an Ariel rudder in good condition, that would be great. Otherwise it looks like a new rudder for my boat.

    Now I do have a question. Many sail boats boats have stainless steel engine shafts and stainless steel rudder shafts. And many of those same boats also have bronze through hull fittings, bronze sea cocks etc. The Pearson Ariel has a bronze rudder shaft and a bronze rudder shoe. It certainly makes sense to use one metal for both components, but with the split Ariel rudder shaft, it appears that you cannot protect the rudder upper shaft with a rudder zinc without destroying the mahogany rudder blade, which through some research and personal experience appears to be a poor solution on a wood rudder and a poor solution on any wood boat for that matter...or it appears so from what I have recently read.

    This is a quote from a wooden boat forum: "The reason that anodes on wooden boats are often NOT suggested is that the electrolytic action induced by the anode destroys the wood in the areas immediately surrounding the anode."

    So has anyone actually had problems with a one piece stainless feel rudders shaft used on a Pearson Ariel with a bronze rudder shoe? I am considering a stainless steel shaft with a stainless steel reinforced rudder blade and the existing bronze rudder shoe. I have spoken in person to one owner who experienced failure of a bronze rudder bolt on a newer stainless steel rudder shaft. What have you all experienced?
    Scott

  3. #18
    Join Date
    Sep 2001
    Location
    San Rafael, CA
    Posts
    3,549

    Sun quest One Piece SS rudder shaft

    Scott, As I said, there is literature on the mix of stainless steel shaft
    in a bronze shoe.
    Stainless attacks the bronze. I don't think it matters what alloy S.S.
    The homemade rudder in A338 had one-piece stainless rudder shaft.
    A zinc had been directly attached to the rudder shoe by removing
    one of the pins and bolting on the zinc.

    The bronze shoe was significantly eaten away, forget which side,
    The shoe was loose. As I say, there is text to find on the phenomenon.

    So, to be sure this gets across, altho I do not know the history of my
    Ariel before I got it, WE cannot use a rudder with a stainless steel shaft
    with the bronze shoe. A-338 wrote the book.

    Fastening-sick wood is in the same neighborhood as galvanic corrosion.

    If you are using zinc, you are creating galvanic corrosion. NEVER mix
    metals under water. Wait until you notice something happening with
    your regular maintenance. Then attach a small anode with a wary eye.

    Don't wire your underwater metal thruhulls and seacocks together.
    ISOLATE THEM. Install Marelon.

    If you build a new rudder, two-piece or single, isolate every connection
    with TEFGEL. Where you have metal faces touching, even the rudder
    socket in the rudder shoe,Tefgel that too. Tefgel all metal to metal in the
    tiller/head assembly. Stop electric pathways wherever possible.

    I recommend, INSIST, that ALL metal in your traditional (original plank)
    rudder be Everdur 655 silicon bronze. That can't be stated any more plain.
    All interconnections, metal to metal are made with Tefgel. Simple.

    If you do this, you will need no zinc, no galvanic connections in the water.

    I extensively rebuilt the whole rear end of A-338. Rebent straight the
    remaining metal of the ruddershoe and with bondo made a model, and
    had California Casting in Richmond cast a new shoe. There was little
    fiberglass in the moistly resin "keel post" at bottom - nothing for the
    shoe to grab. Just saying you may by now in time have some little probs..

    I still believe the original Ariel/Commander rudder is a work of art, worthy
    of reproduction, using the best materials and methods.
    The three planks that made up the rudder blade are not glued together.
    Planks are 'strung' together with 3/8" internal rods.
    There is no glue used in the original rudder. When out of the water the
    wood is allowed to shrink (BUT NOT DRY OUT). Once back in its element
    the Honduras will swell back to its rudderness, as it's done for 50 years ! !
    THAT'S one hell-of-a-mahogany.
    Last edited by ebb; 08-01-2018 at 09:20 AM.

  4. #19
    Join Date
    Sep 2001
    Location
    Orinda, California
    Posts
    2,249
    Re: protecting the upper half of the rudder shaft. Our fix is to use half of a battery jump cable with one end clamp removed and replaced with an anode. Clamp the cable to the top of the rudder shaft under the tiller head fitting and drop the anode end overboard. Been doing this for 30 years and have needed to replace a bunch of anodes (and a few jump cables), but no upper rudder shaft corrosion. No zincs on wood problems.

  5. #20
    Join Date
    Sep 2001
    Location
    Santa Cruz, California
    Posts
    447
    Thank you Bill,

    I appreciate your experience based recommendation.

    In addition to all of the discussion on galvanic action caused by dissimilar metals on a boat, a "hot" harbor can cause damage to any metallic underwater fitting, regardless of the meal used.Your solution address that problem.

    I am not quite sure how you were able to clamp the jumper cable to the top of the rudder shaft under the tiller head fitting. Are you connecting the clamp to the rudder shaft or to the tiller head fitting beneath the tiller?

    FYI, Martyr makes a removable zinc anode and a removable aluminum anode. I have never used one, but you can find them online with a search for:

    Martyr CMGROUPERZ Zinc Alloy Grouper Hanging Anode Zinc


    Regards,

    Scott
    Scott

  6. #21
    Join Date
    Sep 2001
    Location
    Orinda, California
    Posts
    2,249
    To the tiller head fitting. BTW, there is another zinc attached to the rudder shoe to cover the lower half of the shaft.

  7. #22
    Join Date
    Sep 2001
    Location
    Orinda, California
    Posts
    2,249
    Scott, the Grouper Hanging Anode looks just like my "jumper cable" arrangement, but maybe more expensive if you can't replace the exhausted anode.

  8. #23
    Join Date
    Sep 2002
    Location
    Southern Maryland
    Posts
    262
    I'll wade into this conversation knowing that discussion of electrolysis and galvanic action begins to sound more like a fight over which religion is better....
    but here goes...

    I can remember 15 or so years ago when I had to rebuild #3's rudder, I also had to replace the rudder shaft.

    The original rudder was the two-part shaft style with a prop cutout.
    At some point, a previous owner had put one of those flat, round zincs through the back of the rudder, not touching any of the metal bits.
    At that point in time, it was ~ 40 years old or so.
    By that point, the upper rudder was looking very pink-ish.

    so I made the decision to replace the 2-part shaft and broken mahogany rudder with a single shaft and a plywood/fiberglass version of the same shape.

    I'd have to go back in the archives here, but my recollection was that I agonized over which material to get for the shaft, in part because the upper part was looking very pink-ish.
    Now, it had little to no cathodic protection during that entire 40 years, so that should not be surprising for a 40-year old hunk of bronze with no cathodic protection.

    When all was said and done, I ended up re-using shoe and using a bronze (of some sort) shaft. and then put a zinc on the shoe. I just drilled a hole all the way at the bottom from port to starboard and put two tear-drop zincs on either side, with one big thru-bolt.

    So while I appreciate all the discussion of which bronze is best, etc, I think that all of that can be essentially obviated with any sort of protection.

    As to the stainless-bronze issue, again this seems overblown. almost every boat out there with an inboard engine has a stainless shaft and bronze prop. so we just slap a zinc on there and call it good.

    As to the issue of zincs eating the mahogany, I can see that because the manner that an anode helps is by creating OH- ions which are very basic on the pH scale. bases are quite harmful to organic material (think Draino). But as long as there is any sort of space between the zinc and the wood, it should be fine. The issue is when you trap the OH- ions at the wood (like under a zinc bolted to the wood). so don't put your zinc on that way.
    The "grouper" or my zinc at the shoe avoids it, and I'm sure there are other creative ways to accomplish it.

    Just as a bit of perspective, Ariels and Commanders both went into service about the same time as the USS Enterprise.
    She has since been retired....
    In that time, almost every piece of metal touching the sea had been inspected, repaired, or replaced at least once, often many more times.

    If you have to replace a rudder shaft every 40 years or so, I say that's a "win".
    -km
    aka, "sell out"
    S/V Beyond the Sea
    C&C 35 mkIII

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