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Tham khảo tài liệu 'ship stability for masters and mates 5 episode 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Moments of statical stability 129 But LLf y fan 0 gihi 1 yfan 0 The volume of the wedge 2 y2 tan 0 dx The moment of the vertical shift 2 y2 tan 0 dx X 1 y tan 0 1 y3 tan2 0 dx The vertical moment of all such wedges I y3 tan2 0 dx Jo j I tan2 0 The moment of the vertical shift j I tan2 0 Also V X 2gh B1B2 1 2 v or V X b 2vgh but 2vgh The vertical moment of the shift V X b j I tan2 0 or b I tan2 0 V 2 BM tan2 e D1D2 ---------------------p Referring to Figure 14.5 a GZ NR BR - BN BS SR - BN a cos 0 b sin 0 BG sin 0 BM tan 0 cos 0 I BM tan2 0 sin 0 BG sin 0 from a and b BM sin 0 I BM tan2 0 sin 0 BG sin 0 sin e BM j BM tan2 e - BG GZ sin0 GM j BMtan2 0 for 0 up to 25 130 Ship Stability for Masters and Mates This is the Wall-sided formula. Note. This formula may be used to obtain the GZ at any angle of heel so long as the ship s side at WW1 is parallel to LL1 but for small angles of heel 0 up to 5 the term jBMtan2 0 may be omitted. Example 1 A ship of 6000 tonnes displacement has KB 3 m KM 6 m and KG 5.5 m. Find the moment of statical stability at 25 degrees heel. GZ GM 2 BM tan2 0 sin 0 0.5 2 X 3 X tan2 25 sin 25 0.8262 sin 25 GZ 0.35 m Moment of statical stability W X GZ 6000 X 0.35 Moment of statical stability 2100 tonnes m Example 2 A box-shaped vessel 65 m X 12 m X 8 m has KG 4 m and is floating in salt water upright on an even keel at 4 m draft F and A. Calculate the moments of statical stability at a 5 degrees and b 25 degrees heel. W L X B X draft X 1.025 65 X 12 X 4 X 1.025 tonnes W 3198 tonnes KB BM KM KG GM At 5 heel B2 KB 1 draft BM 12d KB 2 m 12 X 12 12 X 4 BM 3 m 2 m 3 m 5 m 4m 1m GZ GM sin 0 1 X sin 5 GZ 0.0872 Moment of statical stability W X GZ 3198 X 0.0872 278.9 tonnes m Moments of statical stability 131 At 25 heel GZ GM 2 BM tan2 0 sin 0 1 1 X 3 X tan2 25 sin 25 1 0.32Ó2 sin 25 1.3262sin25 GZ 0.5Ó metres Moment of statical stability W X GZ 3198 X 0.5Ó 1790.9 tonnesm Ans. a 278.9 tonnes m and b 1790.9 tonnes m. The moment of statical stability at a .
