Page 79 - Introduction to Naval Architecture

66 FLOTATION AND STABILITY

Table 4.2

Inclination sin (p SG sin <p sz GZ
(") m in m

0 0 0 0 0
15 0,259 0.093 0.11 0,203
30 0.500 0.180 0.36 0.540
45 0.707 0.255 0.58 0.835
60 0.866 0.312 0.38 0.692
75 0.966 0.348 -0.05 0.298
90 1.000 0.360 -0.60 -0.240

Transverse movement of weight
Sometimes a weight moves permanently across the ship. Perhaps a
piece of cargo has not been properly secured and moves when the ship
rolls. If the weight of the item is w and it moves horizontally through a
distance h, there will be a corresponding horizontal shift of the ship's
centre of gravity, GGj = wh/W, where Wis the weight of the ship, Figure
4.28. The value of GZis reduced by GGj cos <p and the modified righting
arm = GZ- (wh/W) cos <p,
Unlike the case of the suspended weight, the weight will not in general
return to its original position when the ship rolls in the opposite
direction. If it doesn't the righting lever, and righting moment, are
reduced for inclinations to one side and increased for angles on the

Figure 4.28 Transverse weight shift