Ship Design and Performance for Masters and Mates (eBook)

Cover 1
Ship Design and Performance for Masters and Mates 4
Contents 6
Acknowledgements 10
Introduction 12
Part 1 Ship Design 14
1 Preliminary estimates for new ships: Main Dimensions 16
Estimations of the length for a new design 18
Method 1: Cube root format 18
Method 2: The geosim procedure 20
Method 3: Graphical intersection procedure 21
Selection of LBP values for graphs 24
Depth Mld (D) for the new design 27
Freeboard (f) on Oil Tankers 27
Optimisation of the Main Dimensions and C[sub(B)] 28
Increase of L 28
Increase in B 28
Increases in Depth Mld and Draft Mld 28
Increase in C[sub(B)] 28
2 Preliminary estimates for group weights for a new ship 30
Section 1 30
Estimation of steel weight for a new ship 30
Consideration of steel weight estimations 30
Methods for estimating steel weight in ships 31
Cubic Number method 31
Weight per metre run method 32
The ‘slog-slog’ method 33
Method of differences 33
Modification for C[sub(B)] 34
Scantling correction 35
Deck sheer correction 35
Computational techniques 36
Prefabrication techniques – a short note 37
Section 2 38
Wood and Outfit weight 38
Method 1: The coefficient procedure 38
Method 2: Proportional procedure 38
Non-ferrous metals 40
Use of plastics for Merchant ships 40
Section 3 41
Estimations of machinery weight 41
Method 1: The rate procedure 41
Method 2: Use of empirical formulae 43
3 Preliminary capacities for a new ship 47
Detailed estimation of the Grain Capacity 48
Cargo oil capacity for Oil Tankers 50
Capacity estimate for a Bulk Carrier 51
4 Approximate hydrostatic particulars 53
C[sub(B)] values 53
C[sub(W)] values 54
Displacements 56
KB or vertical centre of buoyancy values 56
BM[sub(T)] values 57
Transverse Metacentre (KM[sub(T)]) 57
Waterplane area (WPA) 58
Tonnes per centimetre immersion (TPC) 58
Moment to change trim one centimetre (MCTC) 58
BM[sub(L)] values 58
Longitudinal Metacentre values (KM[sub(L)]) 60
Hydrostatic curves 60
Transverse Metacentric height (GM[sub(T)]) 61
Some comparisons 61
Comparison between BM[sub(T)] and BM[sub(L)] 63
KG or vertical centre of gravity values 63
Relationship between draft, W, C[sub(B)] and C[sub(W)] 64
Longitudinal centre of buoyancy 65
Summary 65
5 Types of ship resistance 67
Frictional resistance 67
Froude’s speed–length law 69
Froude number 69
Relationship between Froude’s speed–length law and Froude’s Number 69
Residual resistance 70
Total resistance 70
Wind and appendage allowances 71
To find speed of the ship 72
To find the wetted service area of the ship 73
Naked effective power 73
Procedure steps for solving ship resistance and P[sub(NE)] problems 73
Three more important geosim relationships 74
6 Types of ship speed 76
7 Types of power in ships 81
8 Power coefficients on ships 87
Quasi Propulsive Coefficient 87
Propulsive Coefficient 88
Admiralty Coefficient 88
An approximation for Admiralty Coefficient 89
9 Preliminary design methods for a ship's propeller and rudder 95
Propeller design 95
Summary remarks 99
Rudder design 100
Size of the steering gear machinery for turning the rudder 102
Nomenclature for ship design and performance 104
Part 2 Ship Performance 114
10 Modern Merchant Ships 116
Oil Tankers 116
Product/Chemical Carriers 117
OBOs and Ore Carriers 117
Bulk Carriers 117
General Cargo ships 118
Gas Carriers 118
Passenger Liners 118
Container ships 119
RO-RO vessels and ferries 119
Tugs 120
Hydrofoils/Hovercraft 121
SWATH designs 121
11 Ships of this Millennium 122
Standard ships 127
12 Ship Trials: a typical 'Diary of Events' 129
Pro-forma details 130
Completion of vessel construction programme 130
Dry-docking of vessel 131
Undock to basin 131
Ship Trial programme 131
Day 1 131
Day 2 132
Day 3 132
Certificate of Registry and the Carving Note 132
13 Ship Trials: speed performance on the measured mile 133
Precautions 133
Data measured 135
Estimation of a Ship’s Trial speed 136
Method 1 136
Method 2 137
Progressive Speed Trials 140
14 Ship Trials: endurance and fuel consumption 145
Engine settings during Ship Trials 145
Fuel consumption values 146
Method 1 146
Method 2 146
Conclusions 148
15 Ship Trials: manoeuvring trials and stopping characteristics 150
Spiral manoeuvre 150
Zig-zag manoeuvre 150
Turning circle diameter trials 152
Crash-stop manoeuvres 153
16 Ship Trials: residual trials 157
Anchor/cable/windlass trials (as per Lloyds Rules) 157
Anchor lowering and hoisting tests 157
Windlass design and testing 157
Astern trials 158
Rudder helm trials 158
Transverse-thruster propulsion unit trials 158
‘Hand-roll’ test for hydraulic-fin stabilisers 159
Bollard pull trials 159
Navigation instrumentation checks 160
Communications equipment testing 160
Tank integrity tests 160
Main and auxiliary power checks 160
Lifeboat and release chutes release tests 160
Accommodation checklists 160
17 Ship squat in open water and in confined channels 161
What exactly is ship squat? 161
Why has ship squat become so important in the last 40 years? 162
Recent ship groundings 163
Department of Transport ‘M’ notices 163
What are the factors governing ship squat? 164
Squat formulae 164
Ship squat for ships with static trim 171
Squats at both ends of a vessel in open water 172
Procedures for reducing ship squat 174
False drafts 175
Summary 175
18 Reduced ship speed and decreased propeller revolutions in shallow waters 177
Width of influence 177
Depth of influence 178
Loss of speed and decrease in propeller revolutions for ships in shallow water 186
H/T considerations 186
Blockage factor considerations 187
Conclusions 191
19 The phenomena of Interaction of ships in confined waters 193
What exactly is Interaction? 193
Ship to ground (squat) Interaction 194
Ship to ship Interaction 198
Methods for reducing the effects of Interaction in Cases 1–7 200
Ship to shore Interaction 200
Summary 203
20 Ship vibration 204
Causes of vibration 208
Reduction of vibration on ships already built 208
Which propeller to fit? 210
Ship vibration frequency calculations 212
Some vibration approximations 213
Conclusions for Worked example 20.2 213
21 Performance enhancement in ship-handling mechanisms 215
Ship-handling mechanisms 215
Becker twisted rudder 215
Schilling rudders 215
Schilling VecTwin rudders 215
Activated stabilising tanks 216
Tee-duct in Fore Peak Tank 217
Brake flaps 217
Submerged parachutes 218
Stern fins 218
Hinged tail flap in rudder 219
Kort nozzle 221
Kort rudder 221
Bulbous bows 223
Rotating cylinder rudders 223
Hydraulic fin stabilisers 224
Twin-hull ships 225
Double-skin hulls 225
John Crane Lips rudders 225
Rudder fins 226
Stern tunnel 227
Activated rudder 228
Pleuger rudder 229
Hull form of ship 229
Engine type 229
Hull surface polymer paints 229
Planned maintenance 229
Asymmetrical stern 229
Retrofits 230
22 Improvements in propeller performance 231
Voith-Schneider Propulsion unit 231
Transverse thrusters 233
Schottel thrusters 233
Grim vane wheel 234
Groningen Propeller Technology propeller 234
Propeller Boss Cap Fins 236
Voith cycloidal rudder 237
Pods 238
Steerpropulsion contra-rotating propellers 240
Conclusions 240
Useful design and performance formulae 241
Preliminary estimates for dimensions 241
Estimates for steel weight 241
Estimates for wood and outfit weight 241
Estimates for machinery weight 242
Estimates for capacities 242
Approximate hydrostatics 242
Ship resistance 243
Types of ship speed 244
Types of power 244
Power coefficients 244
Propeller and rudder design 245
Bollard pulls 245
Speed Trials 245
Fuel consumption trials 245
Crash-stop manoeuvres 246
Ship squat 246
Reduced speed and loss of revolutions 246
Interaction 246
Ship vibration 247
Revision one-liners for student's examination preparation 248
How to pass examinations in Maritime Studies 252
Before your examination 252
In your examination 253
References 254
Answers to questions 256
Index 260
A 260
B 260
C 260
D 261
E 261
F 261
G 261
H 262
I 262
J 262
K 262
L 262
M 262
N 262
O 262
P 263
Q 263
R 263
S 263
T 264
V 265
W 265
Z 265