4-5.4

component of moment acting about the vessel's vertical "Z"-axis. This moment is

determined from the equation:

(24)

EQUATION:

)*L*

where

= current yaw moment (newton*m)

= transverse current force (newton)

= ratio of eccentricity to vessel waterline length

= eccentricity of *F*yc

(m)

= vessel waterline length (m)

The dimensionless moment arm

is calculated by choosing the slope and y-intercept

variables from Table 4-10 which are a function of the vessel hull. The dimensionless

moment arm is dependent upon the current angle to the vessel, as shown in Equation

25:

= *a *+ *b **θc

θc=0 to 180

(25)

EQUATION:

= *a *+ (*b ** (360 deg- θc )) θc=180 to 360

(25a)

where

= ratio of eccentricity to vessel waterline length

= y-intercept (refer to Table 4-10) (dimensionless)

= slope per degree (refer to Table 4-10)

θc

= current angle (degrees)

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