[alberg30] Rudder project continued

[John Birch]

Tom;

The Rods should be Bronze, Silicon Bronze, not stainless steel as it will become
active when enclosed in the wood and corrode. Stainless should never be denied
air as it becomes Active rather than Passive, look to any good table of noble to
less noble metals.

The bronze should be drilled and tapped into the rudder shaft at 90o, use a jig
and drill press as this is critical. A blind hole 3/4 of the way through, tapped
the full depth, would be best to prevent the rod from worming through the front
of the rudder and jamming against the dead wood.

I would add external strapping and to make it hydrodynamically invisible would
route the boards 3/16 - 1/4" depending on the silicon bronze strap thickness,
fastened with copper, or bronze rivets right through.  There should be 3 straps,
one at each, rudder post as the post is divided at the propellor cutaway.

   * 1 strap near the bottom pin but not over top of the drift rods that you have
     drilled for.
   * 2nd strap near the intermediate point again not over the drilled rods
     running into the post.
   * 3rd just above the aperature but again not over the bronze rods going into
     the post.

Do not over tighten the rods as the rudder will expand when submerged along its
width.  Use quarter sawn mahogany or better - teak.

At our Club we have some teak taken from HMS Victory's Refit in the early 1990s
at Portsmouth, from below the waterline, this was pre Trafalgar (1805) teak
because the subsequent repairs were in oak.   The ship was originally planked in
teak, I believe in 1769.   The teak was in remarkably good shape but the oak it
was attached to was riddled with worm and rot.  The teak now forms the base for
the Victory Trophy with the blackened worm eaten oak forming the "decorative"
upper part of the trophy.   It is quite a conversation piece to be sure.

Glassing over solid wood is always going to give you grief in the long run, as
the wood will expand along its width and crack the glass, letting in more
moisture and expanding the crack. Then when hauled the moisture cannot leave and
voilà, rot begins.

I digress, the point is that using teak and not glassing it over will result in a
rudder that will last you the longest, unless you back into something and always
lift the boat out of the water by the counter and turn the rudder to make sure
you haven't got it trapped by the sling.

Contact Wooden Boat for more info.

Great project, good luck.

John

Rap1208 at aol.com wrote:

> From: Rap1208 at aol.com
>
> Tom, good move on the name change!  Glad the pictures will be helpfull.  I
> haven't seen a rudder apart, but one old, neglected example in my yard, had
> the wooden pieces drifting apart.  It was made of more or less verticle
> boards, with what appeared to be long pins connecting them.  My Ariel had an
> arrangement much like that.  I drifted the pins in with a hammer and large
> punch, and the boards tightened up. ( I also classed it over)   Also might be
> very long threaded bronze rods, I'm not sure.  but the rudder can be
> constructed with mahogony, and glassed over, if you like.  Guess you'll have
> to inprovise.  Long threaded rods, bronze or stainless, brased or welded to
> the rudder shaft would work.  you have to carefuly drill the boards , then
> slide them on.  About 3, I would guess, then counter sink slightly at the
> trailing edge, and use nuts to tighten.  YOU CAN DO IT
>
> Russ
>
> 
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