On Fri, 16 Feb 2007 17:13:14 GMT, Don W
wrote:

Don't some windvanes also have their own rudder to
steer the boat? That's a serious advantage in the
event of a main steering or rudder failure in
heavy seas.

Yes, for offshore bluewater sailing that is a nice plus, and of course
those are the conditions where a windvane adds a lot of value as a
self steering system.

For coastal cruising however a redundant rudder is really not all that
necessary.