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8.3 Designing lines to minimise power ...................... 239
8.3.1 The LCB position ........................... 239
8.3.2 The sectional area curve ........................ 241
8.4 Drawing lines using a basis ship ........................ 244
8.4.1 Retaining the same LCB position ................... 245
8.4.2 Changing the LCB position ...................... 245
8.4.3 Designing lines direct from a sectional area curve ........... 246
8.4.4 Mathematical lines generation ..................... 246
8.5 Twin-screw lines and appendages ....................... 247
8.5.1 Bossing or shaft brackets ....................... 247
8.5.2 Twin skeg forms ............................ 247
8.6 High stability lines ............................... 248
8.6.1 General discussion ........................... 248
8.6.2 Ways of achieving a high KM ..................... 249
8.6.3 Filling out the waterline ........................ 249
8.6.4 V sections and high rise of floor .................... 251
8.6.5 Flared form .............................. 252
8.7 Seakeeping and manoeuvrability ........................ 253
8.7.1 Seakeeping .............................. 253
8.7.2 Shipping water on deck ........................ 253
8.7.3 Pitching motions ............................ 253
8.7.4 Rolling motions ............................ 254
8.7.5 Slamming ............................... 255
8.7.6 Broaching ............................... 255
8.7.7 Ship motion calculations ........................ 257
8.7.8 Course stability and manoeuvrability ................. 257
8.7.9 Manoeuvrability ............................ 258
8.7.10 Ship manoeuvring calculations .................... 260
8.8 The lines above the water line ......................... 260
8.8.1 Section shape ............................. 260
8.8.2 Deck lines ............................... 261
8.8.3 Knuckles ................................ 262

Chapter 9 . Machinery Selection

9.1 Introduction and criteria for choosing the main engine ............ 263
9 . I . 2 Required horsepower ......................... 264
9.1.3 Weight ................................. 264
9.1.4 Space ................................. 264
9.1.5 Capitalcost .............................. 264
9.1.6 Running costs ............................. 265
9.1.7 The ship's requirement for electrical power and heat .......... 266
9.1.8 Reliability and maintainability ..................... 266