Peter Wiley wrote:

Balanced spade rudders with only one support for the shaft - at the top
- are far more prone to failure than rudders with top & bottom support
as provided by a full keel.

Thought that was obvious.

Keep in mind the discussion is seaworthiness, not performance.

Well, a spade rudder hung on a post, with no other support, can be strong
enough. It takes more care with the engineering & materials than most
mass-produced boats can muster.

One of the problems I've seen is that high loads on these type rudders tend
to increase play at the bearings & bushings, which then results in impulse
loads as it begins slamming back & forth. Then the post starts to bend more
on each cycle and fatigues more rapidly. Next thing you know, all you've
got down there is twisted stub.

Another great flaw in 99% of production boats is that the emergency tiller
is laughable.

Fresh Breezes- Doug King