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ABS Guide for Dynamic Positioning Systems
ABS SEMINAR: ABS GUIDE FOR DYNAMIC POSITIONING SYSTEMS
Sue WangSenior Managing Principal Engineer, Offshore
Singapore1 March 2013
2
Objective and Agenda
� Introduce ABS Guide for DP systems to industry
� Seek industry feedbacks and comments
� Part 1: Overview of
� DP system
� ABS Guide for DP systems
� Part 2: New optional Notations for
� Enhanced DP system (EHS)
� Station keeping performance (SKP)
3
up
to 7
0s
80
s
90
-95
96
-99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
20
07
20
08
20
09
20
10
20
11
20
12
up
Rapid Expansion of DP Demand
� Deep-water activity
� More complex field development
� Wider range of application
� Advancement of technology
4
Dynamic Positioning Applications
� MODUs (drillships and semisubmersibles)
� Offshore support, installation and maintenance vessels
� Pipe- and cable laying
� Dredging
� Offloading shuttle tankers
� Cruise ships, large motor yachts
� DP-assisted mooring
� FPSOs in deepwater
� Others
5
Basic DP Principles
� A dynamic positioning (DP) control system automatically calculates the forces that the thrusters, propulsors and steering gear must produce in order to control the vessel’s position and heading
� The DP control systems algorithm's will generate control signals to the thrusters, propulsors and steering gear to obtain the force and moment required for the requested position and heading control
6
What Do We Need for DP?
� Power
� Thrusters and rudders
� Position measurement
� Position filtering (LF)
� Control algorithm (positive required force)
� Thruster and rudder allocation
7
Elements of a DP System
7
DP Operator
Human-Machine
Interface
Computer
Operator Panel
Display Screen
DP Controller
(DPC)Power Syste
m
SensorsCompass
WindVertical Reference
DraftTension
Position Reference Systems (PRS)
DGPSUnderwater Acoustics
LaserMicrowaveTautwire
Thrusters
8
Typical DP System Layout
ControllerOperator
Station
Tunnel
Thruster
Azimuth
Thruster
Propulsion
Thruster
Rudder
Hardwire
or LAN
9
How DP System Work
VESSEL THRUST
EKF PID
Measured
Position
ALLOC
Wind
Waves
Current
(T,α)1..n
=
f(Fx, Fy, Mz)0 1 2 3 4 5 6 7 8 9 10
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
time/T0 [-]
X/X
0 [
-]
1+e(- βω
ot)
1-e(-βω
ot)
β = 0.1
β = 0.3
β = 0.5
β = 0.7
β = 1
β = 0.05
X0
10
Basic Elements DP Control System
Thrusters
Power, Sensors, Position References
11
Common Position Measurement Equipment
� Fan Beam (Laser Technique)
� Taut Wire (Vertical Angle)
� DGPS (Satellite)
� HPR (Long and Short Base, Hydro-acoustic, Transponders)
� Atriums (Radio Wave, Landmark, Specific-Site)
� Others
12
DP System Vendors
� Kongsberg Maritime
� Converteam (GE)
� L-3
� Marine Technologies
� Navis Engineering
� Rolls-Royce
� Nautronix
� Others
13
Basic Elements of a Power System
14
Thrusters & Rudders
� Main propellers
� Bow and stern thrusters
� Azimuthing thrusters
� Retractable thrusters
� Rudders
15
DP Guidelines from Related Organizations
� IMO MSC Circular 645
� IMO MODU Code
� ISO 19901-7 Stationkeeping
� US Coast Guard
� Norwegian Maritime Directorate (NMD)
� Flag State
� International Marine Contractors Association (IMCA)
� Marine Technology Society (MTS)
� American Petroleum Institute (API)
� Class Societies
16
IMO & ABS DP Equipment Class
� IMO Class 1
� For equipment class 1, loss of position may occur in the event of a
single fault
� ABS DPS-1
� For vessels which are fitted with a dynamic positioning system which
is capable of automatically maintaining the position and heading of
the vessel under specified maximum environmental conditions
having an independent centralized manual position control with
automatic heading control
17
IMO & ABS DP Equipment Class
� IMO Equipment Class 2
� A loss of position is not to occur in the event of a single fault in any
active component or system (generators, thrusters, switchboards,
remote controlled valves, etc.)
� Normally static components will not be considered to fail
� ABS DPS-2
� For vessels which are fitted with a dynamic positioning system which
is capable of automatically maintaining the position and heading of
the vessel within a specified operating envelope under specified
maximum environmental conditions during and following any single
fault, excluding a loss of compartment or compartments
18
IMO & ABS DP Equipment Class
� IMO Class 3
� For equipment Class 3, a single failure includes items listed previous
for Class 2, and any normally static component is assumed to fail
� All components in any watertight and fire protected compartment
� ABS DPS-3
� For vessels which are fitted with a dynamic positioning system which
is capable of automatically maintaining the position and heading of
the vessel within a specified operating envelope under specified
maximum environmental conditions during and following any single
fault, including complete loss of a compartment due to fire or flood
19
Selection of DP Equipment Class
� DP equipment class governed by the type of operations
� Norwegian Maritime Directorate (NMD) has specified
� DP units of Class 1 should be used during operations where loss of
position is not considered to endanger human lives, cause significant
damage or cause more than minimal pollution
� DP units of Class 2 should be used during operations where loss of
position could cause personnel injury, pollution or damage with great
economic consequences
� DP units of Class 3 should be used during operations where loss of
position could cause fatal accidents, severe pollution or damage with
major economic consequences
20
Guidelines for DP Equipment Class
Operation NORSOK MTSOne Oil
CompanyRemark
Drilling 3 2 32
Diving inside structures 3 2 3
Diving in open water 2 2 3
Pipelay/umbilical lay 2 2 33
Lifting 2 2 3
Shuttle Offtake 2 2 2
ROV Support (Open water) 1
ROV Support (Close Proximity - Surface/Subsea) 2 2 2
Floating Production (HC production) 3 2
Well intervention 2 21
32
Logistics Operations 21
2
Subsea well workover 3 32
Accomodation (ganway connection to installation) 3 2 3
Accomodation (outside 500m safety zone) 2
Construction activies inside 500m general 2 2
Construction activies outside 500m general 1
1 Vessels of lesser Class may be
used with the appropriate
structured risk identification and
mitigation measures in place
2 Class 2 acceptable with extra fire
watch and engine control watch
routines
3 Class 3 for Norwegian
Continental Shelf. For others, Class
2 accetable with Extra fire watch
and engine control watch routines
USCG: Class 2 or above for MODU
according to IMO MODU Code
21
ABS DPS Rules & Guides & Notations
� ABS Guide for Thrusters and Dynamic Positioning System (1994) was incorporated in the Rules for Building and Classing Steel Vessels, 4-3-5/15 in 2000
� ABS Guide for Dynamic Positioning Systems (December 2012)
� DPS Basic Notations
� DPS-0, DPS-1, DPS-2, DPS-3
� Inline with IMO Guidelines for Vessels with Dynamic Positioning
Systems (1994)
� Supplement Notations
� EHS-P, EHS-C, EHS-F
� SKP, SKP(a,b,c,d,e,f)
� Incorporate new development
� Provide flexibility
22
DPS Notations
� Notation DPS-0
� Most basic system
� No redundancy
� Centralized manual position control with automatic heading control
(joystick)
� Notation DPS-1
� No redundancy
� One automatic position and heading control computer
� Independent manual position control with automatic heading control
(joystick)
23
DPS Notations
� Notation DPS-2
� Redundancy design and able to maintain position and heading with
a single fault
� Redundant(2) automatic position and heading control computers
� Independent manual position control with automatic heading control
(joystick)
� Notation DPS-3
� Redundancy design with physical separation and able to maintain
position and heading with a single fault and loss of a compartment
due to fire or flood
� Redundant(3) automatic position and heading control computers
� Independent manual position control with automatic heading control
(joystick)
24
Dynamic Positioning Systems
Items DPS Notation
0 1 2 3
Power System No Redundancy No Redundancy Redundancy Redundancy
Power management No No Yes Yes
UPS No Yes Yes Yes
Thruster System No Redundancy No Redundancy Redundancy Redundancy Automatic Control Computers
0 1 2 3
Manual Position Control with Auto heading
1 1 1 1
Manual Independent Thruster Control at Bridge
Yes Yes Yes Yes
Position Reference 1 2 3 3
Gyro Compass 1 2 3 3
MRU 0 2 3 3 Wind Sensors 1 2 3 3
Consequence Analyzer
No No Yes Yes
FMEA No No Yes Yes
25
Other ABS Rules Related to DP Components
� ABS Steel Vessels Rules� Diesel Engines – Section 4-2-1� Gas Turbines – Section 4-2-3� Electric Motors and Motor Controllers – Section 4-8-3� Gears – Section 4-3-1� Shafting – Section 4-3-2 � Propellers – Section 4-3-3� Piping System – Chapter 4-6 � Thrusters 4-3-5� Control Equipment and Systems – Section 4-9-7
� ABS MODU Rules� Pumps and Piping Systems – Chapter 4-2� Electrical Installation – Chapter 4-3� Rules for Equipment and Machinery Certification – Part 6� Surveys – Part 7
� ABS Rules for Survey After Construction� Machinery Surveys – Chapter 7-6� Shipboard Automatic and Remote-control Systems – Chapter 7-8� Survey Requirements for Additional Systems and Services – Chapter 7-9
26
Guide Development Background
� ABS updating Rules as routine process
� Industry demanding
� Wide range application of DP systems
� Flexibility
� Stationkeeping performance
� Reflect industry advancement
� Robust redundancy design concept
� Enhanced generator protection technology
� Rapid automatic blackout recovery
27
Innovation & New Technology
� Robust redundancy concept
� Advanced computing technology
� Enhanced FMEA process
� Advancement of sensor technology
� Advanced generator protection
� Advanced thruster control and protection
� Quick black-out recovery
� Comprehensive operation monitoring
27
28
Gap Analysis
� Level of details
� Lack of specifications
� Closed bus design
� Criteria for stationkeeping performance
� Enhanced features
� Advanced generator protection and control
� Blackout prevention and automatic quick recovery
� Robust redundancy concept
� Fire and flood protection of machinery space (for DPS-2)
� Higher availability and reliability of position reference systems
and sensors
29
Overview DPS Guide Development
� Major update for current ABS DPS Notations
� DPS-1
� DPS-2
� DPS-3
� Development of new optional notations
� DP system enhancement notation (EHS)
� Stationkeeping performance notation (SKP)
� Objective
� Reflect Industry advancement
� Provide flexibility
� Encourage higher design standards and consistent assessment
30
Highlight of DPS Guide
� Definitions to form a common basis of understanding
� Requirements on documentations for quality and completeness
� Increased level of details on technical requirements
� New enhanced system notations (EHS)
� Recognition of design features beyond DPS-series notations
� Encourage higher safe design standard
� Provide flexibility to owners and operators
� New stationkeeping performance notation (SKP)
� Recognition of DP capability
� Encourage robust design and consistent assessment
� Increased level of details on testing
� Vessel type and activity specifics
31
Content of DPS Guide
� General
� DP System Design
� Power System
� Thruster System
� Control System
� Marine Auxiliary System
� Initial Test of DP System
� Enhanced DP System
� Stationkeeping Performance
� Specific Vessel Types
� Other Optional DP System Notations
32
Section 1-3: Definitions
� Specified maximum environmental condition
� Specified operating envelope
� Single fault
� Dynamically positioned vessel
� Dynamic positioning system
� Industry mission
� Power system
� Thruster system
� DP control system
� Position reference system
� Joystick system
� Static component
� Active component
� Worst case failure
� Worst case failure design intent
� Consequence analysis
� DP capability analysis
� Redundancy concept
� Critical redundancy
� Redundant groups
� Autonomous system
� Closed bus
� Common mod failure
� Single fault tolerance
� Independence
� Loss of position
� Stationkeeping
33
Section 1-4: Documentations
� List of documentation (level of detail)
� Dynamic positioning system
� Power system
� Thruster system
� DP control system
� Documentation type (level of detail)
� R: Documentation for review
� I: Documentation for information and verification for consistency with
related review
� OB: Documentation needs to be kept onboard
� Added documents
� Basic design of DP system redundancy (R DPS-2 and DPS-3)
� Planned inspection and maintenance (I)
34
Section 2: Dynamic Positioning System Design
� 1 General
� 3 DP System Technical Requirements� 3.1 Basic requirement� 3.3 Redundancy design� 3.5 Physical separation � 3.7 DP system equipment requirements� 3.9 Stationkeeping performance
� 5 Essential non-DP Systems� 5.1 General� 5.2 Emergency shut down system and DP redundancy� 5.3 Fire protection and DP redundancy� 5.4 Fuel quick closing valves and DP redundancy
� 7 Alarms and Instrumentation
� 9 Communications and DP Alter System� 9.1 Communications� 9.2 DP alter system
� 11 Failure Mode and Effects Analysis� 11.1 Failure mode analysis� 11.2 FMEA report
� 13 DP Operations Manual
35
Section 2: Dynamic Positioning System Design
� Increased level of details for easy use
� Content of documents
� FMEA
– Failure modes
– FMEA analysis report
– FMEA proving trial report
� DP Operations Manual
� Stationkeeping performance analysis
� FMEA and Proving Trial Report (OB)
� After completion of DP proving sea trials, the final version of DP FMEA and
DP proving trial report, including final analysis and conclusions based on
actual results from DP testing, are to be submitted
� Updated after major modifications
36
Section 3: Power System
� 1 General
� 3 Power Generation System
� 5 Power Distribution System
� 7 Power Management System
� 9 Uninterruptible Power Systems (UPS)
37
Section 3: Power System
� Level of details for easy use
� Closed bus tie breaker (DPS-2 and DPS-3)
� Capable of breaking the maximum short circuit current in the
combined system
� Coordinated in relation to generator breakers to avoid total loss of
main power (blackout)
� Two bus tie breakers are to be provided between bus sections
� Closed bus for DPS-3
� Consideration of EHS-P requirements
� If all thrusters are direct diesel drive, no need for a power management system
38
Section 4: Thruster System
� 1 General
� 3 Thruster Capacity
� 5 Thruster Configuration
� 7 Thruster Auxiliary System
� 9 Thruster Control
� 11 Thruster Monitoring and Alarm
� Level of details for easy use
39
Section 5: DP Control System
� 1 General
� 3 DP Control Station
� 5 DP Control System
� 7 Manual Position Control System
� 9 Control Mode Selection
� 11 Position Reference System and Environment Sensor
� 13 Consequence Analysis (For DPS-2/3)
� 15 Display and Monitoring
� Level of details for easy use
40
Section 5: DP Control System
� DP Control Station
� Main DP control station with good viewing of the external surrounding area
and all activities relevant to the DP operation
� Backup DP control station, a night vision, closed-circuit TV (CCTV) system
is acceptable for viewing the external surrounding area
� Data Communication Networks
� Communication network for DP control system is to be duplicated for
DPS-2 and also separated for DPS-3
� Manual position control system is not to share the same communication
network with the DP control system
� Control Mode Selection
� Easy operational device to be provided in the DP control station for the
selection of the thruster control modes
� Transfer of control to the backup DP control station to be initiated at backup
control station and performed manually
41
Section 5/11: Position Reference System & Wind Sensor
� One set of position reference system
� GPS (others, position measurement devices)
� Gyro (heading measurement device)
� MRU (others, roll and pitch measurement for position correction)
� MRU: where position reference systems are dependent on correction of roll and pitch effect, MRU or equivalent is to be provided
� Position reference systems and wind sensors to be powered by UPSs and follow group redundancy concept
42
Section 6: Marine Auxiliary System (DPS 2/3)
� 1 General
� 3 Fuel Oil
� 5 Cooling Water
� 7 Compressed Air
� 9 Lubrication Oil Systems
� 11 HVAC and Ventilation
� 13 Piping
� 15 Pneumatic Systems
� 17 Power Supply to Auxiliary Systems
� Level of details for easy use
43
Section 6: Marine Auxiliary System (DPS 2/3)
� Auxiliary systems to be arranged in accordance with the redundancy concept
� A single failure effect analysis for auxiliary systems to be included in the DP system FMEA
� Fuel water content monitoring with remote alarms is to be installed
� Power for auxiliary systems associated with DP systems is to be taken from within the redundancy group
44
Section 7: DP System Initial Test
� 1 General
� 3 DP System Performance Test
� 5 FMEA Proving Trial for DPS-2/DPS-3
� Level of details
45
Section 7: System Performance Test
� 30 minute UPS Test
� Position Reference Systems and Sensors
� Manual Position Control System
� Manual Thruster Control System
� Thruster Emergency Stop
� DP Control System
� Control and Alarms
� Standby Changeover
� Protection equipment are to be tested if they are designed to provide essential redundancy of the DP system
� 6-hour Performance Endurance Test
46
Section 7: FMEA Proving Trial for DPS-2/DPS-3
� FMEA tests to confirm the findings from FMEA analysis
� Test procedures are to be developed in the FMEA analysis
� Vessel is to operate in configurations analyzed in DP system FMEA
� Submit final version of DP FMEA including conclusions from the testing
47
Section 8: Enhanced System
� New Notations
� EHS-P for enhanced power plant and thruster system
� EHS-C for enhanced control system
� EHS-F for fire and flood tolerance design
� Supplement information for DPS-2/DPS-3 Notations
� Provide three groups for flexibility and easy recognition
� Can be combined as EHS-PC, etc.
� Objective
� Improve reliability, operability and maintainability
� Recognize safety features that beyond minimum requirements
� Encourage higher safe design standard
48
Enhanced Propulsion System EHS-P
� Applicable to DPS-2 and DPS-3 system
� Features on power plant protection and quick blackout recovery
� High safety measurement against closed bus operation
� Targeting reduced consequence of failure
49
EHS-P Requirement
� Enhanced generator protection
� Failure detection and discrimination of failed components before a
full or partial black-out situation occurs
� Open bus-tie if the faulty generator fails to trip
� One protection system per generator
� Robust redundancy design
� Autonomous generator sets
� Autonomous thruster sets
� Blackout prevention and automatic recovery (60s)
� Power management system
� Thruster phase back
� System ride through capability (short circuit)
50
EHS-P Requirement
� Autonomous
� Control and automation – to be decentralized to the point that each
item of main machinery (generators and thrusters) is capable of
making itself ready for DP operations independently of any
centralized control system
� Auxiliary – to be provided in a manner that makes the machinery
(generators and thrusters) as independent as practical to minimize
the number of failures that can lead to the loss of more than one
main item of machinery
51
Enhanced Control System EHS-C
� Applicable to DPS-2 and DPS-3 system
� Aiming for higher availability and reliability of input data to the control system
� Statistics point to the necessary of improvement
� Encourage for higher design standard
DP Computer
Environment
Power Generation
Operator Error
References
Thruster
Electrical
Incidents that led to loss of position
1994-2007
DP Computer 62
Environment 40
Power Generation 50
Operator Error 89
References 103
Thruster 76
Electrical 22
Total 442
52
EHS-C Requirement
� Three position reference systems and sensors available at any given time and location
� Four position reference systems and four sensors with combination of different systems
� Redundancy of relative reference system for offshore support vessels
� Three DP control computers (one backup)
� Equipment from different suppliers or using different principles of operation
� DP Data Logger
� Integration of the centralized control system with sub-control systems
53
Fire & Flood Tolerance Design EHS-F
� Applicable to DPS-2 system
� Provide another level of measurement for fire and flood tolerance design
� Focus on fire risk spaces
� Flexibility for diversified market needs
54
EHS-F Requirement
� DPS-3 automatically meets EHS-F requirements
� A-0 separation along boundary of redundancy groups
� No A-0 separation required between main and backup DP control station
� A-60 separation for high fire risk spaces
� The high fire risk area is the area defined by SVR 4-8-4/1.11
including
� Machinery spaces as defined by 4-7-1/11.15 and 4-7-1/11.17
� Spaces containing fuel treatment equipment and other highly
flammable substances
55
Summary of Enhanced DP Systems
EHS-P EHS-C EHS-F
Autonomous Generator Set2+1 Backup DP Control
computers and controllersGenerators and Prime Movers
Separate compartments, A60 for
high fire risk area. Watertight
below damage waterline.
Bus Tie Breakerredundantly configured
between each bus segment
Wind Sensors3 + 1 in back up control station
Enhanced Generator Protection
Gyros3 + 1 in backup control station
Power Distribution SystemA0 between redundant groups.
Watertight below damage waterline.
Enhanced Power Management
MRU3 + 1 in backup control station
Thruster SystemA0 between redundant groups.
Watertight below damage waterline.
Autonomous Thruster SetPosition Reference Systems
3 + 1 in backup control stationController Space
A0 between redundant groups.
56
Closed Bus
� Enhanced system design (EHS-P)
� Improvement of active redundancy
� Reduce consequence after failure
� At least two or more generators running and they are connected to two or more sections of the main bus
� The worst case failure of the configuration is not to result to a blackout
� Spinning reserve is to be able to make up at least 50% lost capacity after the worst case failure of the operating mode in consideration
� Other 50% lost capacity can be provided from the standby units
57
Standby Start
� Changeover is to be automatic
� Position and heading of the vessel are within the specified limits and DP
performance is not degrading
� Maximum allowed changeover time is 45s
� Single fault does not cause total blackout including loss of entire
compartment for DPS-3
� A failure in one redundancy group is not to cause failure of more than
one redundancy groups
� A failure in the system being changed over to is not to cause failure of
more than one redundancy groups
� Changeover is not to cause failure of the redundancy group that is being
connected to
� At least, one standby generator is to be considered not available when
needed
58
FMEA & Test (EHS)
� Operation of protection systems (breakers, bus ties, etc.) related to short circuit
� Severe voltage dips associated with short circuit faults in power plant configured as a common power system
� Failure to excess and insufficient fuel
� Over and under-excitation
� Governor and AVR failure modes
� Failure modes related to standby start and changeover
� Power management failure on load sharing, malfunction, etc.
� Phase back thrust and large load
� Blackout recovery
59
Documentation (EHS)
� Description of protection design philosophy and protection systems the redundancy concept of DP system depends on
� Analysis of effects of severe voltage transients on power system stability
� Short circuit analysis
� Simulation of severe over/under voltage and over/under frequency
� Protection coordination analysis
� Protection settings
� Description of automatic blackout recovery
60
Section 9: Stationkeeping Performance
� New notations
� SKP: verification for given design environmental conditions through
analysis
� SKP(a,b,c,d,e,f): determine limiting environments for a given
environment site through analysis
� Supplement for DPS-series notations
� Objective
� Recognition of DP capability
� Encourage robust design and consistent assessment
61
SKP Notation
� Owner specify design environment conditions
� Design wind speed and directions
� Design wave height, related period and directions
� Design current speed and directions
� Station keeping performance assessment
� Environmental load calculation
� Available thrust calculation including effect due to thruster
interference with others
� Analysis results demonstrate the capability of stationkeeping for the specified environment conditions
62
Result Presentation for SKP
Total Thrust Utilization Plot for given Environment Condition
63
Environmental Load
� Wind and current
� 1-minute mean wind speed at 10-meter above water surface
� Model test data to be used whenever possible
� For non-ship shape unit, wind and current forces according to
ABS Rules for MODU, FPI or API 2SK
� For a ship shape unit, wind and forces according to ABS Rules for
MODU, FPI, API RP 2SK or OCIMF publication
� Wave
� Significant wave heights and characteristic periods (frequencies)
� JONSWAP for North Sea and locations with limited fetch
� Bretschneider for open seas
� Model test data for wave drift force if available
� Drift force calculation using appropriate hydrodynamic analysis
computer program
64
Available Thrust
� Manufacturer’s test data of full scale or suitable model test for the thrust output of thrusters to be used
� This Guide provides method for determining available thrust
� Thruster-Thruster Interaction
� Thruster-Hull Interaction
� Thruster-Current Interaction
65
DP Capability
Courtesy: MTS/Shell
Predicted CapabilityReal Capability
66
SKP(a,b,c,d,e,f) Notation
� a: the probability that the vessel can remain on station with all thrusters operating for location f and current speed e
� b: the probability that the vessel can remain on station with the failure of minimum effect of single thruster for location f and current speed e
� c: the probability that the vessel can remain on station with the failure of maximum effect single thruster for location f and current speed e
� d: the probability that the vessel can remain on station with the worst case failure condition for location f and current speed e
� e: current speed in knot (owner specify or typical 1.5 kt)
� f: environment location (owner specify or typical North Sea)
67
SKP(a,b,c,d,e,f) Notation
� Same analysis procedures for load and thrust calculation
� May cover SKP if design environments are given and are within the limit
� Require for the relationship between wind speeds and wave heights
� Require probability of non-exceedance of wind speed
68
Wind & Wave Relationship (North Sea)
69
Result Presentation for SKP(a,b,c,d)
Typical DP Capability Plot
70
Section 9: Sub-sections
� 1 General
� 1.1 Definition
� 1.1.1 SKP
� 1.1.2 SKP (a,b,c,d)
� 1.1.3 Normal Operation Condition
� 1.1.4 Standby Condition
� 3 Environmental Condition
� 3.1 Wind
� 3.3 Wave
� 3.5 Current
� 3.7 Environment for SKP
� 3.9 Environment for SKP (a,b,c,d)
� 5 Analysis Conditions
� 5.1 DP System Configurations
� 5.3 Operation Conditions
� 7 Environmental Load Calculation
� 7.1 Wind and current force
� 7.3 Wave force
� 9 Other External Load
� 11 Available Thrust
� 11.1 Available Thrust for Thrusters
� 11.3 Thruster-Thruster Interaction
� 11.5 Thruster-Hull Interaction
� 11.7 Thruster-Current Interaction
� 11.9 Available Thrust for Transverse
Tunnel Thrusters
� 13 Rudder Force
� 15 SKP Calculation
� 15.1 SKP Notation
� 15.3 SKP (a,b,c,d) Notation
� 17 Documentation
71
Documentation
� Where the DP system is to be supplemented with a stationkeeping performance notation, the following information is to be submitted for review
� General arrangement and lines plan
� Thruster arrangement
� Thruster power and thrust
� Thruster interactions
� Analysis procedures
� Capability plots
� Documentation on the environment conditions long term distribution
(any area for intended service)
� Owner specified limiting environments
72
Section 10: Specific Vessel Types
� 1 Introduction
� 3 Mobile Offshore Drilling Units
� Effect of drilling
� Effect of emergency shutdown system
� Effect of emergency disconnect system
� Maintenance plan
� 5 Project or Construction Vessels
� Suitable DP Control modes
� Redundancy of relative position reference system
� 7 Logistics Vessels
� Redundancy of relative position reference system
73
DPS Guide Development Milestones
Project Plan
Initial development
work
Jan 2012 Oct 2012
Rough Draft for DP
consultants review and
improvement
Jun 2012 Aug 2012
DPS draft guide development
Industry workshop
Project KickoffDivisions
TechnologyTBDs
Previous DP Consultant work
Internal and external review
Consultantfeedback
Dec 2012
DPS Guide
Review feedback
74
Summary
� DPS Guide to reduce the gaps between industry practices and class requirements
� New notations for enhanced system (EHS) and stationkeeping performance (SKP)
� Provide systematic measurement
� Provide more flexibility for owners and operators
� Need industry feedbacks for further improvement
Shipbuilder
Underwriter
Charterer
ShippingFinancier
Classification Society
Flag State
Port State
SHIPOWNER
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