I wouldn't have a hinged rudder as you describe, or
someone has to prove it can be done first.
Too many parts and things to go wrong in my
opinion. Fullsize HP rudders have to be very strong, one piece seems to be
best.
The huge loads on the rudders calculated for BD
have made me think of other solutions, but if two full size rudders work well
that may be the simplest solution when shunting and number of parts needing
attention for best performance.
Reducing rudder area would make them less
vulnerable but has to be compensated.
BD will have full size beam mounted rudders. Plan
is to get it sailing next spring.
Rudolf
----- Original Message -----From: Gardner PomperSent: Thursday, November 06, 2008 4:00 PMSubject: [harryproa] Crazy rudder ideaI once owned a one-tonne IOR racing boat from the 1970s, from a designer named Carter. He was known for his swing keels. We had 7000 lbs of lead that gave us a 7' draft when it was down, and a 4.5' draft when it was up. The really neat thing about it was that it was a hydrofoil in both positions.
The reason I bring this up, is that it seems like the same could be done with a rudder. If we took the Blind Date rudder, which is about 5' by 1.5' and hinged it where the rudder post attaches inside the rudder, about 17-20% back from the top and leading edge, it could be used as a deep draft rudder normally, then flipped up (manually or by a grounding) to a 1.5' draft with the same square footage steering surface.By having the hinge below the water line, we could support the rudder post in 2 places.. the beam and a strut out from the hull.If we are worried about surface level impacts, the hull strut could decouple and the shaft could be hinged again up higher, near the beam.It seems that this could be simple to construct, would not have to be as strong (since it has support below the beam) and provides alot of rudder surface at low speed in shallow water for shunting.Anyone think this idea might be practical?- Gardner
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