Q6. A ship of 8000 tonne displacement has a rudder area of 22 m2. The ship has a KM of 6.7 m, KG of 6.1 m and the centre of lateral resistance is 3.8m above the keel.
The maximum rudder angle is 35oand the centroid of the rudder is 2.3 m above the keel.
The force generated normal to the plane of the rudder is given by
F = 580 Av2 sin α
Where: A = rudder area
V = ship speed in m/s
α = rudder helm angle
Calculate EACH of the following, when the vessel is travelling at 20 knots:
(a) the angle and direction of heel due to the rudder force only, if it is put hard over to port; (8)
(b) the angle and direction of heel due to the combination of centrifugal force and rudder force when the rudder is hard over to port and the vessel tums in a circle of 800 m diameter. (8)
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