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DNVGL-RP-E306 Dynamic Positioning Vessel Design

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DNVGL-RP-E306 Dynamic Positioning Vessel Design RECOMMENDED PRACTICE DNVGL-RP-E306 Edition July 2015 Dynamic positioning vessel design philosophy guidelines The electronic pdf version of this document found through http://www.dnvgl.com is the officially binding version. The documents are available free of charge in PDF format. DNV GL AS FOREWORD DNV GL recommended practices contain sound engineering practice and guidance. © DNV GL AS July 2015 Any comments may be sent by e-mail to [email protected] This service document has been prepared based on available knowledge, technology and/or information at the time of issuance of this document. The use of this document by others than DNV GL is at the user's sole risk. DNV GL does not accept any liability or responsibility for loss or damages resulting from any use of this document. CHANGES – CURRENT General This document supersedes DNV-RP-E306, September 2012. Text affected by the main changes in this edition is highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour. Main changes July 2015 • General The revision of this document is part of the DNV GL merger, updating the previous DNV service document into a DNV GL format including updated nomenclature and document reference numbering. Changes – current Recommended practice, DNVGL-RP-E306 – Edition July 2015 Page 3 DNV GL AS CONTENTS CHANGES – CURRENT .................................................................................................. 3 Sec.1 Introduction................................................................................................ 10 1.1 Introduction......................................................................................10 1.2 Purpose.............................................................................................10 1.3 General guidance ..............................................................................11 1.4 Layout of the document ....................................................................12 Contents 1.5 Definitions and abbreviations............................................................13 Sec.2 Dynamic positioning vessel design philosophy ............................................ 18 2.1 Responsibilities .................................................................................18 2.2 Reliability of station keeping.............................................................19 2.3 Key attributes of a robust dynamic positioning system .....................20 2.4 Dynamic positioning equipment class ...............................................21 2.5 Dynamic positioning equipment class 1 ............................................21 2.6 Dynamic positioning equipment class 2.............................................22 2.7 Dynamic positioning equipment class 3.............................................22 2.8 Classification society dynamic positioning notations.........................22 2.9 Functional requirements ...................................................................22 2.10 Time to terminate .............................................................................23 2.11 Mitigation of failures .........................................................................23 2.12 Redundancy concept and worst case failure design intent ................23 2.13 Availability and post failure dynamic positioning capability ..............24 2.14 External factors.................................................................................25 2.15 Key elements of dynamic positioning system performance ..............26 2.16 Key elements of redundant systems..................................................26 2.17 Communicating and supporting the redundancy concept ..................27 2.18 Connections between redundant systems .........................................28 2.19 Multiple power plant configurations ..................................................28 2.20 Critical and non-critical redundancy..................................................28 2.21 Autonomy and decentralization.........................................................28 2.22 Orthogonality, diversity and differentiation ......................................29 2.23 Cost effective risk reduction..............................................................29 2.24 Enhancing class minimum standard ..................................................30 2.25 Influence of the vessel’s industrial mission.......................................30 2.26 Regulatory requirements ..................................................................31 Sec.3 Capability .................................................................................................... 32 3.1 Initial design process........................................................................32 3.2 Capability plots .................................................................................32 3.3 Environmental forces ........................................................................33 3.4 Thrusters ..........................................................................................33 3.5 Capability plots for intact and failure cases.......................................34 3.6 Presentation of capability plots.........................................................34 3.7 Basic plots.........................................................................................34 3.8 Comprehensive plots.........................................................................34 Recommended practice, DNVGL-RP-E306 – Edition July 2015 Page 4 DNV GL AS Sec.4 Modeling ..................................................................................................... 36 4.1 Scope of modeling.............................................................................36 4.2 Naval architecture.............................................................................36 4.3 Modeling by example ........................................................................36 4.4 Analytical modeling...........................................................................36 4.5 Hull form modeling............................................................................36 4.6 Power and safety systems.................................................................37 4.7 Operability parameters .....................................................................37 Contents 4.8 Prior example....................................................................................37 4.9 Analytical modeling...........................................................................38 4.10 Physical hull form modeling ..............................................................38 4.11 Power systems..................................................................................39 4.12 Operability parameters .....................................................................39 Sec.5 Management of change in design ............................................................... 40 5.1 Requirements for management of change.........................................40 5.2 Management of change examples .....................................................40 Sec.6 Thrusters .................................................................................................... 42 6.1 Principles ..........................................................................................42 6.2 Propulsion choices ............................................................................42 6.3 Design basis criteria..........................................................................43 6.4 Propulsion concepts ..........................................................................44 6.5 Location and geometrical arrangement of the propulsors ................45 6.6 Thruster-thruster interaction ...........................................................46 6.7 Thruster-hull interaction ..................................................................46 6.8 Hydrophone interaction ....................................................................46 6.9 Minimum number of thrusters ..........................................................46 6.10 Thruster handling requirements over lifecycle ..................................46 6.11 Basic thruster hydrodynamic aspects................................................46 6.12 Thruster drive systems .....................................................................47 6.13 Control of thrust................................................................................47 6.14 Controllable pitch propellers .............................................................48 6.15 Thruster variable speed drives ..........................................................48 6.16 Maintainability and maintenance of thrusters ...................................51 6.17 Testing of thrusters...........................................................................51 6.18 Vibration measurements ...................................................................52 6.19 Operation of the thrusters ................................................................52 6.20 Mechanical design of the right-angle gear thrusters .........................53 6.21 Propeller shaft seals..........................................................................53 6.22 Thruster propellers ...........................................................................54 6.23 Thruster selection criteria .................................................................54 6.24
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