Question 3.SQ.1: Repeat the calculations in Example 3.3, but this time: (a) ......
Repeat the calculations in Example 3.3, but this time:
(a) reduce the load carried by the pontoon to 1500 × 10³ N, 1400 × 10³ N and 1100 × 10³ N and determine what effect this has on the value of GM;
(b) keep the load at 1600 × 10³ N as in Example 3.3, but investigate the effect on GM of increasing the width of the pontoon to 7.5 m, 8.0 m and 9.0 m while assuming that its weight is unaffected at 700 × 10³ N.
The calculations follow the same procedure as in Example 3.3. Thus:
(a) With load = 1500 × 10³ N, total weight = 2200 × 10³ N, V = 218.79 m³, h = 2.08 m, OB = 1.04 m, OG = 2.86 m, BG = 1.82 m, BM = 1.96 m, GM = 0.14 m. Improved stability but GM is still small, remembering that the calculations may be slightly inaccurate. With load = 1400 × 10³ N, total weight = 2100 × 10³ N, V = 208.85 m³, h = 1.99 m, OB = 1.00 m, OG = 2.83 m, BG = 1.83 m, BM = 2.05 m, GM = 0.22 m. Better, but GM still relatively small. With load = 1100 × 10³ N, total weight = 1800 × 10³ N, V = 179.01 m³, h = 1.70 m, OB = 0.85 m, OG = 2.72 m, BG = 1.87 m, BM = 2.40 m, GM = 0.53 m. Relatively stable.
(b) With b = 7.5 m, total weight = 2300 × 10³ N, V = 228.74 m³, h = 2.03 m, OB = 1.02 m, OG = 2.89 m, BG = 1.87 m, BM = 2.31 m, GM = 0.44 m. Significantly improved stability. With b = 8.0 m, total weight = 2300 × 10³ N, V = 228.74 m³, h = 1.91 m, OB = 0.95 m, OG = 2.89 m, BG = 1.94 m, BM = 2.80 m, GM = 0.86 m. With b = 9.0 m, total weight = 2300 × 10³ N, V = 228.74 m³, h = 1.69 m, OB = 0.85 m, OG = 2.89 m, BG = 2.04 m, BM = 3.98 m, GM = 1.94 m. Very stable, but is period of roll too short?