It wasn't a spade rudder, with no skeg. Look at the drawings which Blye original posted of the hull design, and you'd notice that. The little thing and notch along the trailing edge of the keel extension about a 1/3rd of the way down the rudder :^)))

http://www.canadianyachting.ca/boat-reviews/sail/64-cs-36-traditional-sail-boat-review I have excerpted the review below.

"[W]all was unwilling to draw a spade rudder, as many other designers had done by 1977, and so the rudder is a partial skeg with a bolt on a bearing midway down the rudder. Nor did Wall draw the lines without a traditional sheer. Compared to an Alberg 37 (a 1960s boat) its sheer it quite flat, but there is definitely some traditional up-sweeping curved sheer forward of the cockpit. At 15,500 lbs, it has a relatively heavy displacement compared with the CS 36 Merlin, which floated at 13,000 lbs. Wall was accustomed to designing boats for North Sea conditions and the CS 36 Traditional was billed as an offshore cruiser. "

I guess that the Valiant 40 would seem to you like a Chevy Corvair? NOT! They probably have more round-the-world credentials out of the box than any cruiser over the years. Anyway...

Blye, I'd like your friends views and information on the following to better understand what happened:

1) If the "rudder disappeared", then did the shell of the rudder fall-off? Was the post there at all? Did the "skin" fall-off? for the rudder shear vertically?

2) In order for the rudder to drop off, I believe that both a) the bottom pin would have to be gone; and b) the rudder post would have to drop-out. That would mean the quadrant would have to release the shaft. Any thoughts on that?

3) What was repaired previously and "fixed"? It's possible that the pin was damaged originally -- or in the reinstallation?

Since I can't help myself (again), I guess that somehow the Mr. Perry's Valiant 40 isn't a "proper" ocean going design for a rudder for you barn door guys? ;^))))

A poorly designed spade rudder, like a deep fin keel, is a disaster waiting to happen. I suppose you don't have to be too sophisticated to design and build a barn door ;^)))

I think that a spade rudder is vulnerable to hitting things than a barn door; but a properly designed one is more likely to steer you where you want to go if you're trying to avoid something -- forgetting the velocity issues. They certainly are more likely to allow you control yourself in wave train (unless you're down below for the duration) ;^))).