Re: Is external rudder a good idea?
Al my designs have out board rudders as I consider it the only intelligent place to put a rudder on an offshore cruiser. As the Pardys pointed out "They put rudders on the back of a plane instead of the middle for good reason."It drastically simplifies self steering and inside steering, or autohelm steering via a trimtab on it's trailing edge, making such systems exponentially stronger than any of the options available for inboard rudders.
I see no real advantages for an inboard rudder on an offshore boat ,and can't understand why so many designers make that obvious mistake.
Lack of offshore cruising experience among them may be one reason.
Brent Swain, Yacht designer, Builder, and author of "Origami Metal Boatbuilding"