Dave Gerr - Boat Mechanical Systems Handbook-How to Design, Install, and Recognize Proper Systems in Boats

previous chapter), so the rudder on the inside
of the turn angles more than the outside
rudder. In addition, because they are acting in
tandem, these twin rudders can turn effec-
tively to as much as 75 degrees on the

inboard-turn rudder and 55 degrees on the

outboard. To get such high angles, the rud-

ders must have a half fishtail on the outside

of each blade. You can see this if you study

Figure 13-13 closely.

Chapter 13:Unusual and Special Rudders

Figure 13-12.

Geometry of a

Deflector Rudder

Figure 13-13.

Double fixed-

geometry high-lift

rudders (Courtesy

Jastram Canada

Ltd.)