Overview

This book bridges the knowledge gap between the users of dynamic positioning (DP) and the knowledge encapsulated in sources such as DP system manuals, onboard documentation, IMO publications, class society rules and regulations, IMCA guidelines and research papers. This book has been updated to MSC.1/Circ.1580 and its text is quoted in italics.

It is a challenge to deal with a subject as complex as DP and with features differing between systems. DP vessels vary in shape, size and role, with often very little in common in their operating procedures, e.g. a diving vessel and an FPSO. This book comprehensively explains the principles and procedures of DP for all users.

In this second edition, a chapter on DP incident investigation has been added, an important function for SDPOs. The scope of Chapters 17–23 on mission-specific operations has been broadened to enable bespoke project planning. These chapters in Part V should be read in conjunction with chapters in Part I dealing with generic DP operations.

Content

About the Author
Introduction
Acknowledgements

Part I – Theory of Dynamic Positioning
1 Offshore Environment 
1.1 Development of Dynamic Positioning 
1.2 Offshore Structures 
1.3 Types of DP Vessels 
1.4 Underwater Vehicles 

2 Components of a DP System
2.1 Definitions 
2.2 Components of a Dynamic Positioning System 
2.2.1 The Vessel Model 
2.2.2 Thrusters 
2.2.3 Controller 
2.2.4 Position Reference System (PRS) 
2.2.5 Sensors 
2.2.6 Power System 
2.2.7 Human-Machine Interface (HMI) 
2.3 Modes of DP Operation 
2.4 Independent Joystick System (IJS) 
2.5 Centre of Rotation 

3 DP System Architecture 
3.1 Guidelines for DP Vessels 
3.2 Concept of DP Redundancy 
3.2.1 Elements of Redundancy 
3.2.2 Attributes of a Redundant DP System 
3.2.3 Levels of Redundancy =
3.3 IMO Classification of DP Vessels 
3.3.1 Worst-Case Failure Design Intent (WCFDI) and Worst-Case Failure (WCF) 
3.3.2 Equipment Classes 
3.4 Integrated Vessel Management System (IVMS) 
3.4.1 IVMS Components 
3.4.2 IVMS Hierarchy 
3.5 DP Control System 
3.5.1 Controller 
3.5.2 Communication Network 
3.6 Power System 
3.6.1 Components 
3.6.2 Power System Configuration 
3.6.3 Closed Bus-tie Operation  
3.6.4 Uninterruptible Power Supplies (UPS) 
3.6.5 Alternative Energy Storage 
3.6.6 Hybrid DC Distribution Grid 
3.6.7 Power Management System 
3.7 Thruster System 
3.7.1 Thruster Redundancy 
3.7.2 Thruster Combinations 
3.8 Vessel Control System 
3.8.1 Communication, Alarms and Warnings 
3.8.2 Redundancy and Criticality Assessment (RCA) 
3.8.3 Ergonomics 
3.8.4 Cables and Piping System 
3.9 Vessel Safety System 
3.9.1 Fire and Gas System 
3.9.2 Emergency Shutdown (ESD) 
3.9.3 Emergency Disconnect Sequence (EDS) 

4 Position Measurement 
4.1 Position Measurement of a DP Vessel 
4.2 PRS Settings 
4.3 Calibration of a PRS 
4.4 Signal Processing and PRS Tests 
4.4.1 Freeze Test 
4.4.2 Variance Test and Weighting 
4.4.3 Prediction Test 
4.4.4 Divergence Test 
4.4.5 Median Test 
4.4.6 Example of PRS Weighting 
4.5 Common Factor Failure 
4.6 Position Coordinate System 

5 Principles of Dynamic Positioning
5.1 Positioning of a Vessel 
5.2 The Model 
5.2.1 Motion Model of Vessel 
5.2.2 Kalman Filter and Model 
5.2.3 Example of Model Update 
5.3 Error Compensation Force 
5.4 Power Overload Control 
5.5 Dynamic Positioning Process 
5.5.1 DP System Control Loop 
5.5.2 Quick Current (Fast Learn) 
5.5.3 Gain Control 
5.5.4 Model Control (Dead Reckoning) 
5.6 Modelling Errors 
5.6.1 Thruster Demand/Feedback Error 
5.6.2 Wind Sensor Error 
5.6.3 Wave Drift Forces 
5.6.4 Wind Shadow 

6 Position Keeping Capability 
6.1 DP Capability 
6.2 DP Footprint Plots 
6.3 Consequence Analysis 
6.4 DP Capability Plot 
6.4.1 DP Capability Levels – DNV GL 
6.4.2 Most Loaded Thruster 
6.4.3 Drift-off Calculations 

7 Guidelines for Vessels and Units with Dynamic Positioning (DP) Systems (MSC.1/Circ.1580) 

Part II – Planning and Operation

8 Risk Assessment 
8.1 Definitions 
8.2 Hazard Analysis Techniques 
8.3 The Risk Assessment 
8.3.1 Procedure 
8.3.2 Hazard Identification 
8.3.3 Qualitative and Quantitative Risk Assessment (QRA) 
8.3.4 Risk Mitigation 
8.3.5 Record of the Findings 
8.3.6 Review of the Risk Assessment 
8.4 Risk Environment in DP Operations 
8.4.1 Hazards – DP Operations 
8.5 Bow-tie Analysis 

9 DP Operational Planning 
9.1 The Scope 
9.2 Risk Analysis 
9.3 Class Requirement 
9.4 DP Status Alert Levels 
9.5 Operational Activity Planning 
9.5.1 Critical Activity Mode (CAM) 
9.5.2 Task Appropriate Mode (TAM) 
9.5.3 Activity-specific Operating Guidelines (ASOG) 
9.6 DP Capability 
9.7 Positional Information 
9.8 Weather 
9.9 Power Generation and Distribution 
9.10 Position Reference Systems 
9.11 Operation in Shallow Waters and Strong Currents 
9.12 SIMOPS (Simultaneous Operations) 
9.13 DP Vessels Operating in Proximity 
9.14 DP Operations near Floating Objects 
9.15 DP Planned Maintenance 
9.16 Blackout Recovery Drill 
9.17 DP Operations Manual 
9.18 Bridge Management 
9.19 Management of Change (MOC) 
9.20 Documentation and Records 
9.21 Training and Competence 
9.22 DP Emergency Drills 
9.23 Human Factors 
9.24 DP Station Keeping Events 

10 DP Operation and Contingency Plan
10.1 Entering an Oil/Gas Field 
10.2 Selecting a Worksite 
10.3 Entering the 500 m Safety Zone 
10.4 Approaching the Worksite 
10.5 DP Watchkeeping 
10.5.1 Parameters to be Monitored 
10.5.2 Functional Controls 
10.5.3 Warning and Alarm Limits 
10.5.4 DP Watchkeeping Handovers 
10.5.5 Data Logkeeping 
10.6 Handling a DP Vessel 
10.6.1 DP Mode 
10.6.2 Joystick Handling 
10.6.3 Manual Handling 
10.7 Contingency Plan 
10.7.1 Safe Termination and Withdrawal 
10.7.2 Action during Blackout 
10.7.3 Terminating DP Operation 
10.7.4 DP Emergency Response 

Part III – Equipment

11 Position Reference Systems
11.1 Differential GNSS 
11.1.1 Global Positioning System (GPS) 
11.1.2 GLONASS 
11.1.3 Differential Absolute and Relative Positioning System (DARPS) 
11.2 Fanbeam 
11.3 CyScan 
11.4 Artemis 
11.5 Taut Wire 
11.6 RADius 
11.7 RadaScan 
11.8 Hydroacoustic Position Reference System 
11.8.1 Underwater Acoustics 
11.8.2 The HPR system 
11.8.3 Methods of Positioning 
11.8.4 Applications of HPR System 
11.8.5 Operational Limitations of HPR System 
11.9 Hydroacoustic Aided Inertial Navigation (HAIN) System 
11.9.1 Inertial-aided GNSS 

12 Sensors 
12.1 Heading Sensor 
12.2 Motion Sensor 
12.2.1 Roll and Pitch Compensation 
12.2.2 Heave Compensation 
12.3 Wind Sensor 
12.4 Triple Redundancy in Sensors 
12.5 Other Sensors 

13 Thruster System
13.1 Factors Affecting Thrust Capability 
13.2 Thruster Failure Modes 
13.2.1 Hydraulic Failure 
13.2.2 Electrical Failure 
13.3 Thruster Failure Alarms 
13.4 Dealing with Thruster Failure 
13.5 Isolation of a Faulty Thruster 
13.6 System Checks 

Part IV – Surveys, Trials, Failures and Investigation
14 Surveys, Trials and Checks
14.1 Surveys and Testing 
14.2 FMEA and FMECA 
14.2.1 Uses 
14.2.2 The Objectives 
14.2.3 Scope 
14.2.4 FMEA Guidelines and Standards 
14.3 Single Point Failure and Redundancy Criteria 
14.3.1 Failure Modes and Effects 
14.3.2 Common Mode Failure 
14.3.3 Common Cause Failure 
14.3.4 Hidden Failures 
14.3.5 Human Interface Related Failure 
14.3.6 FMEA Tests 
14.3.7 Software FMEA 
14.4 The FMEA Process 
14.5 Concerns 
14.6 FMEA Proving Trials 
14.7 Annual DP Trials 
14.8 FMEA Management 
14.8.1 FMEA Verification 
14.8.2 Management of Change 
14.8.3 Gap Analysis 
14.9 Limitations of FMEA 
14.10 Miscellaneous Surveys 
14.11 Hardware-in-the-Loop (HIL) Testing 
14.12 Dynamic Positioning Verification Acceptance Document (DPVAD) 
14.13 Trials and Checks 
14.14 eCMID and CMID Inspection Report Database 

15 Failures, Emergencies and Incidents
15.1 Trends in DP Incidents 
15.2 Summary of DP Incidents 
15.2.1 Position Reference Systems 
15.2.2 Computer and Systemic Failures 
15.2.3 Model Instability 
15.2.4 Thrusters 
15.2.5 Power 
15.2.6 Sensors 
15.2.7 Joystick 
15.2.8 Human Error 
15.3 Offshore Incidents 
15.3.1 DSV ‘Bibby Topaz’ Incident 
15.3.2 OSV Incident in the US Outer Continental Shelf 

16 DP Incident Investigation 
16.1 The Objective 
16.2 Pre-investigation (Step 1) 
16.3 Initiating the Investigation (Step 2) 
16.4 Gathering and Collating Data (Step 3) 
16.5 Root Cause Analysis (Step 4) 
16.5.1 The Five Whys Method 
16.5.2 Fault Tree Analysis (FTA) 
16.5.3 Fish-bone Diagram 
16.6 Recommendations (Step 5) 
16.7 Trend Analysis (Step 6) 
16.8 Following up an Investigation (Step 7) 
16.9 Learnings from Incident (LFI) 

Part V – Mission-specific DP Operations 

17 Offshore Support Operations
17.1 Offshore Support Vessel (OSV) 
17.2 Responsibilities of Key Personnel 
17.3 DP Status Alert Levels 
17.4 Operational Activity Planning 
17.5 Hazard Identification 
17.6 The OSV Operation 

18 Diving Operations
18.1 Diving Support Vessel (DSV) 
18.2 Responsibilities of Key Personnel 
18.3 Communications 
18.4 DP Status Alert Levels 
18.5 Diving Management System 
18.6 Operational Activity Planning 
18.7 Hazard Identification 
18.7.1 Environmental Factors 
18.7.2 Operational Factors 
18.7.3 Diving Related Factors 
18.8 The Diving Operation 
18.9 Contingency Plan 
18.9.1 DP Emergencies 
18.9.2 Diving Emergencies 
18.9.3 Lost Bell Recovery 
18.9.4 Hyperbaric Evacuation 

19 Pipe Lay Operations
19.1 Pipe Lay Vessel 
19.2 Responsibilities of Key Personnel 
19.3 Communications 
19.4 DP Status Alert Levels 
19.5 Types of Pipe Lay 
19.5.1 S-lay Method 
19.5.2 J-lay Method 
19.5.3 Reel-lay Method 
19.5.4 SnapLay 
19.6 Use of DP in Pipe Lay 
19.7 Operational Activity Planning 
19.8 Hazard Identification 
19.8.1 Environmental Factors 
19.8.2 Operational Factors 
19.8.3 Pipe Lay Factors 
19.8.4 Trenching/Ploughing
19.9 The Pipe Lay Operation 
19.9.1 Pipe Lay Surveys 
19.9.2 Pipe Lay Procedure 
19.10 Contingency Plan 

20 Heavy Lift/Crane Operations
20.1 Heavy Lift/Crane Vessels 
20.2 Responsibilities of Key Personnel 
20.3 Communications 
20.4 DP Status Alert Levels 
20.5 Operating Modes 
20.6 Operational Activity Planning 
20.7 Hazard Identification 
20.7.1 Environmental Factors 
20.7.2 Operational Factors 
20.7.3 Heavy Lift Factors 
20.8 The Heavy Lift Operation 
20.9 Contingency Plan 

21 Shuttle Tanker and FPSO Operations
21.1 Shuttle Tankers 
21.2 Communications 
21.3 DP Status Alert Levels 
21.4 Responsibilities of Key Personnel 
21.5 Offshore Loading Facilities 
21.5.1 Surface Single Point Systems 
21.5.2 Sub-surface Single Point Systems 
21.5.3 Floating Production and Storage Systems 
21.5.4 Direct Offloading 
21.6 Operational Activity Planning 
21.7 Hazard Identification 
21.7.1 Environmental Factors 
21.7.2 Operational Factors 
21.8 The Offtake Operation 
21.9 Contingency Plan 

22 Miscellaneous Mission-specific Operations 
22.1 ROV Support 
22.1.1 ROV Support Vessels 
22.1.2 Operational Activity Planning 
22.1.3 Hazard Identification 
22.1.4 The ROV Support Operation 
22.1.5 Contingency Plan 
22.2 Cable Lay/Repair 
22.2.1 Cable Lay Vessels 
22.2.2 Operational Activity Planning 
22.2.3 The Cable Lay/Repair Operation 
22.3 Accommodation 
22.3.1 Accommodation Vessels 
22.3.2 Operational Activity Planning 
22.3.3 The Operation 
22.4 Dredging 
22.4.1 Dredging Vessels 
22.4.2 Operational Activity Planning 
22.4.3 The Dredging Operation 
22.5 Rock Dumping 
22.5.1 Rock-dumping/Placement Vessels 
22.5.2 Operational Activity Planning 
22.5.3 The Rock-dumping Operation 
22.6 Service Operations 
22.6.1 Service Operations Vessels (SOVs) 
22.6.2 Operational Activity Planning 
22.6.3 The Wind Farm Installation 
22.7 Anchor Handling 
22.7.1 Anchor Handling Tug Supply (AHTS) Vessels 
22.7.2 Operational Activity Planning 
22.7.3 The AHTS Operation 
22.7.4 Emergency Release Arrangements 

23 Offshore Drilling Operations
23.1 Mobile Offshore Drilling Unit (MODU) 
23.2 Responsibilities of Key Personnel 
23.3 Communication 
23.4 DP Status Alert Levels 
23.5 Offshore Drilling 
23.5.1 Preparation 
23.5.2 Stages of Drilling 
23.5.3 Ball Joint and Riser Angle Sensors 
23.5.4 Blowout Prevention 
23.6 Operational Activity Planning 
23.7 Hazard Identification 
23.7.1 Environmental Factors 
23.7.2 Operational Factors 
23.7.3 Well-related Factors 
23.8 The Drilling Operation 
23.9 Contingency Plan 
23.9.1 DP Emergencies 
23.9.2 Gas Detection 
23.9.3 Emergency Disconnect Sequence (EDS) 

Glossary and Abbreviations
Guidance Relating to DP Operations
International Marine Contractors Association (IMCA) 
Marine Technology Society (Dynamic Positioning Committee) 
DNV-GL Rules and Standards 
References

Introduction 

This book bridges the knowledge gap between the users of dynamic positioning (DP) and the knowledge encapsulated in sources such as DP system manuals, onboard documentation, IMO publications, class society rules and regulations, IMCA guidelines and research papers. This book has been updated to MSC.1/Circ.1580 and its text is quoted in italics.

It is a challenge to deal with a subject as complex as DP and with features differing between systems. DP vessels vary in shape, size and role, with often very little in common in their operating procedures, eg a diving vessel and an FPSO. This book comprehensively explains the principles and procedures of DP for all users.

DP differs from other maritime activities and, in effect, is more akin to aviation where the reaction time is usually less and averting a disaster depends solely on the operator’s proficiency, training, team work and reliability of the DP system. The aviation industry has evolved over the years in terms of training and standard operating procedures; DP has a long way to go, but it is heartening to note that, in the past few years, it has made significant strides in the quality of training delivered.

In the recent past there have been a few high profile offshore accidents resulting in fatalities and damage to property and the environment. Education is vital in avoiding future incidents and I sincerely hope that this book will be a small step in bringing about this change.

In the second edition, a chapter on DP incident investigation has been added, an important function for SDPOs. The scope of Chapters 17–23 on mission-specific operations has been broadened to enable bespoke project planning. These chapters in Part V should be read in conjunction with chapters in Part I dealing with generic DP operations. I hope this edition will adequately meet the need of the complete spectrum of DP users.

Details

Title: Dynamic Positioning: Theory & Practices, 2nd Edition
Number of Pages: 242
Product Code: IT103591
ISBN: 978-1-85609-936-3
Published Date: October 2020
Binding Format: Hardback
Book Height: 279 mm
Book Width: 165 mm
Weight: 1.40 kg
Author: Capt KC Shukla