Robert,
You are correct in assuming I used screws. As I said, this was done
purposely. I have screws in both gudgeons. I worried that some day I would
hit a piece of wood or the beach with the rudder down damaging either the
bar or the transom.
Our rudder boxes do not pivot and do not have a shear pin for safety.
During the construction I put a small wood knee in the hull between the
transom and the bottom of the hull. It is laminated with carbon/kevlar and
incorporates drain holes. Good thing.
I do have the option to remove the screws and use bolts backed as you
suggest. But as I said this does worry me.
I think the main reason for the failure is the bending moment on the
pin. The metal spacer must have caused a serious stress raiser on the pin at
the point between the rudder box pin bushing and the spacer. Note that the
pin bent forward i.e. toward the bow. This makes sense to me. Looks like a
pretty straight forward force couple. The rudder is being forced aft by the
water motion (relatively speaking).
What I don't understand is the screws in the lower gudgeon should have
pulled away first as they were under tension. I guess we will never know.
I am contemplating making the rudder box with a pivot mechanism.
Dave Lindsey
> Not knowing how you attached the bottom gudgeon, I can't say for sure but
> I'd agree with Cristian that it looks like you used screws to hold it in.
> There is a lot of force here and you'll want to do backing plates and
> washers. The 1/4" strips and some glass will not hold everyting under load.
>
> The big problem now is getting the pin back out of the cassette without
> ruining the cassette. When you put the gudgeouns back on the boat, make
> sure that you bolt it all on with large washers, 5200, and locking nuts.
> You might have long enough arms to reach from the inspection ports. I lost
> my rudder in a similar way in Florida and had to borrow Mark White's arm.
> I can't get my forearms through the inspection ports. If you did use
> screws, there shouldn't be too much damage to the transom.
>
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