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 1723 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

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 operators 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 1723 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