Dave,
I think you will find that screws are not strong enough to hold the rudder
gudgeons to the transom and transom bar. Planning for something inexpensive
to fail is a good idea, but with screws you will probably be loosing the
rudder every time the wind is blowing 12-15kts. I also had rudder problems
not long ago, my rudder broke just below the rudder box, and in a bit more
wind. There was no damage to the transom bar or either of the gudgeon
blocks, which have three 1/4" bolts in the bottom block and two in the top
block. If you bolt everything up tight, you should not loose the rudder in
the future, just don't go out in 28kts or so and up.
Mark
----- Original Message -----
From: "Dave Lindsey" <lindsey@xxxxxxxxxxx>
To: "Swiftsolo" <swiftsolo@xxxxxxxxxxxx>
Sent: Sunday, September 09, 2007 11:14 PM
Subject: Rudder rip-off
> **Just a little info I thought I would pass onto other builders.**
>
> My rudder pulled off my boat today. Mike offered to sail the Red Violin as
a
> sort of sea trial. It was a beautiful day with winds at about 12-15 kts.
>
> Mike pushed off with no problem. I watched him as he sailed her close
hauled
> west of the pier. Later I watched as he very skilfully doused the main and
> struggled to come in on the jib alone. Eventually it became obvious he
> required some assistance.
>
> The rudder had completely ripped off the boat. See the attached pictures.
>
> I think it is fairly obvious what happened. A strong bending moment bent
the
> pin which lead to the upper gudgeon block pulling away from the bar. I
think
> this lead to the lower end of the pin bending and the whole works falling
> off.
>
> If my assumption is correct, the lesson is that we need to eliminate all
> bending moments on the pin. Do not use a spacer as I did. Keep the rudder
> box attachment point as close to the gudgeons as possible. Shear is
> acceptable, but try to eliminate any and all bending moments.
>
> Now I have to figure out how to fix this mess. Any suggestions. No smart
ass
> remarks please?
>
> Oh, one final point; I used screw (4) to attach the gudgeon to the bar.
I'm
> glad I did. I very purposely wanted this to be a failure point vs.
breaking
> the bar. Now I question if the rudder box should be designed to pivot
with
> a shear pin. Comments?
>
> David Lindsey
> CAN 046
>
>
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