Iranian Classification Society Rules

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Section 3 Rudder Torque


301. Rudder torque

The torque of general type rudder is to be obtained from the following formula.


kN m


: as defined in 201.

: distance (m ) form the center of rudder force on the rudder to the centerline of the rudder stock, determined by the following formula.


m


For the ahead condition, however, is not to be less


mi

obtained from the formula.



min


: mean breadth (m ) of rudder determined by the coordinate system in Fig 4.1.2

as defined in Table 4.1.4

: the balance factors of the rudder obtained from the following formula.


portion of the rudder stock (m )

plate area situated ahead of the centerline of the rudder

: as defined in 201.


image


image

Fig 4.1.2 Coordinate System of Rudders

Pt 4 Hull Equipment

Ch 1 Rudders Pt 4, Ch 1

image


Table 4.1.4 Factor ᾍ


Course of rudder

Ahead condition

0.33

Astern condition

0.66