358 



THEORY OF SEAKEEPING 



Pressure 



1)11 Ise, 285, 28<J 



recnnlors, 55 

 Prisms and cylinders, 



deeply subniorged, 115 



oscilhding on water surface, 115 

 Probabilistic methods, 1(36 

 Probability, 



distribution of wave slopes, 19-21 



joint, 298 

 Products of velocities, 182 

 Projection of wave numbers, 75 

 Propeller, 



a])|)arent slip, 244, 245, 253 



effective pitch, 246 



efficiencj-, 243 



Quasi fully arisen sea, 46 



Quasi static conditions, 290 



Quasi stationary wind conditions, 331 



Queen Elisabeth (SS), 208 



Random, 



distribution, 16, 17 



processes, 17, 58, 60, 61 

 Range of stress variation, 186, 264 

 Rapidly applied loads, 283 

 Rate of load application, 257 

 Rational theory, 257 



Rayleigh distribution, 57, 72, 73, 172, 201, 200 

 Read effect, 257 



Reference velocity or speed, 23, 24 



Region of practical applicability in damping versiis froquoncv 

 plots, 123 



R.PSlSt3tlCG 



addcl'liy wave reflection, 238, 253 



caused by waves and ship motions, 238, 239, 253 



caused by waves directly, 238 



shii>-niodel correlation, 242 



towing tank methods and data, 240-242 



Resonant pendulum, 78 



Response amplitude operator, 169, 173 



Restoring moment (in rolling), 126 



Reverie (s<hooncr), 18 



Righting arm, 126, 160 



Ripples, 14, 17, 22, 23, 25, 73, 329 



Roll stabilization, 159 



Rolling, 1.58 



amplitude decay, 127 



in irregular waves, 176, 177 



in regular waves, 126 



in still water, 126 



linear approximation, 127 



nonlinear, 160, 161 



Root-mean-square (wave amplitude), 72 



Rotary inertia, 292 



Rotating arm, 124, 125 



Rough boundary surface, 332 



Roughness (in relation to wave-covcrod sea), 330 

 of a plate, 328 

 protuberances, 329 



Royal Sovereign (battleship), 129 



Rudder, 209 



control, 164, 180, 181, 215 



control fmictions, 164, 165, 180, 215, 216 

 controlling devices, 163 

 degree of freedom added by, 163 

 effectiveness (as affected by the trim), 215 

 motions, 177, 180, 184, 185, 253 

 response to ship motions, 163 



Sampling 



effects, (il 



interval, 65, 66 



variability, 68-70 

 San Francisco (MS), 17, 138, 186-191, 207, 211, 257. 260-205, 



273, 285, 306, 307 

 Schwartz-Cristoffel transformation. 111, 115 

 Sea 



air temperature difference, 51, 52, 81 



characteristics (description of), 29 



complex (ahso seawav, or wave sv.stem), 21, 24, 35, 36. 45, 72, 

 138, 142 145, 329, 336 



conditions, 281-283 



I'onilitions conducive to slamming, 136 



disturbance n\nnber, 247, 248 



fully developed, 40, 42, 45, 46. 331 



irregular, 54, 145, 161, 164, 206, 211, 283 



quatcring, 124, 165, 178, 204 



regular long-crested, 155 



scale, 247, 249 



short-crested, 24, ISO, 204 



-sickne,ss, 158 



state, 30, 44, 54, 59, 60, 70, 73 



surface variability, 70, 88 

 Seaway (Neumann's description), 330 



fully develoiied, 334 

 Seaplane, 136, 137 



expanding plate theory of imjjact, 136, 137 



impact forces, 137 



landing impact theory, adajitation to ship slamming, 138 

 Sectional forces, 258, 259 

 Seewetteramt, 48 



Separation of air flow at wave crests, 5 

 Series 60, calculated slamming pressures, 140 

 Set up (or inclination) of water surface caused bj' wind, 4-10, 237 

 Seven degrees of freedom, 163, 304 

 Severity of waves, 2S0 283 

 Sharp-crested wave profile, 4-7, 10, 18, 141, 321, 328, 329 



Shear, 



coefficient (effectiv<^ at water surface), 333 



forces, 2.58, 263, 2(;5 



modulus, 292 

 Sheltering coefficient, 20, 23, 328 

 Ship, 



broaching, 125, 165 



forms mathematically defined, 108, 121, 133, 134, 239, 240 



loading while in port, 186 



-made waves, 89, 196, 257, 277, 279 



progressive wave sj'stem. 111, 118, 119 



responses, 61 



responses to rudder movements, 164 



rolling in head and following irregular waves, 178, 200, 204 



roll-stabilyzed, 164 



sections (afterbody), 125 



standing wave system, 111, 118, 119 



steering eharaclcristics, 181, 185 



Shipborne wave recorder (or gage), 34, 55, 56, 73, 78, 85 



Shipbuilders Research Association (dr. Brit.), 248 



Ship forms, 



oscillating on the water surface, 116 

 subjected to wave action, 117 



Ship model motions (comparison of calculated and measured), 155 



Ship motions, 



in till' plane of symmetrv, 153 



observed at sea,"l84, 188. 191, 199, 200, 202, 203, 204, 205 

 prediction of by linear super])Osition theory, 166 

 significant characteristics of, 158 



six component (or in six degrees of freedom). 152, 162 

 two sviperposed systems of oscillations (in undamped rolling), 

 1.59 



Shipping of water, 248 



Shock-absorbing travel (cushioning effect), 141, 142 



Short-crestedness, 16, 75, 82, 8(5, 175, 178, 180, 181 



