DNVGL-OS-E301 Position mooring

1 The electronic pdf version of this document, available free of chargefrom , is the officially binding GL ASOFFSHORE STANDARDSDNVGL-OS-E301 Edition July 2018 Position mooringFOREWORDDNV GL offshore standards contain technical requirements, principles and acceptance criteriarelated to classification of offshore units. DNV GL AS July 2018 Any comments may be sent by e-mail to service document has been prepared based on available knowledge, technology and/or information at the time of issuance of thisdocument. 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 responsibilityfor loss or damages resulting from any use of this document.

2 Changes - currentOffshore standards, DNVGL-OS-E301 . Edition July 2018 Page 3 Position mooringDNV GL ASCHANGES CURRENTThis document supersedes the July 2015 edition of in this document are highlighted in red colour. However, if the changes involve a whole chapter,section or subsection, normally only the title will be in red July 2018 TopicReferenceDescriptionFormer [ ]Removed requirement for 10 000 year environment to bechecked for turret to align with other DNV GL offshore [ ]Added requirements for environment for mobile offshore unitsstaying at a location for less than one [ ]Added guidance regarding peakedness [ ] [ ]Included updates based on results from SquallMoor JIP andprovided guidance for how to assess squalls when time series arenot [ ] [ ]Updated guidance on how to apply directions of wind, wavesand current.

3 Also included requirements to units with headingcontrol, and how to account for uncertainty in setting the [ ]Updated details for how to account for marine growth accordingto latest edition of NORSOK [ ] [ ]Updated requirements on how to calibrate wind and currentcoefficient obtained from [ ] [ ]Updated requirements on how to account for viscous effects andcurrent interaction in mooring [ ]Group and slight update to requirements and guidance on how toaccount for damping in mooring [5]Added reference /6/ regarding wave drift forces and [ ]Moved and updated requirements to thruster assisted mooringanalysis from [ ]New requirement for how to account for corrosion of [ ] [ ]Included clarification for how to account for OPB in [ ]Added guidance note explaining where alternative S-N curvesmay be [8]Added reference 9, 10 og [3]Updated paragraphs to clarify requirements for layout of thrusterassisted mooring updates based onexperience and Table 2 Added more material types as allowable materials to be used.

4 Changes - currentOffshore standards, DNVGL-OS-E301 . Edition July 2018 Page 4 Position mooringDNV GL [ ]Added hot surfaces as a potential source of gas [ ]Added clarifications regarding design life time of gears forwindlass/winch for mobile [14]Updated requirements to mooring line monitoring equipment bydistinguishing between mobile and long term [ ]Added additional requirement for non-redundant structuralmembers in mooring [ ]Added requirements for clashing [ ]Added requirement to twist in chain [ ]Added requirement to avoid wire rope sockets in the touch layout to allign with other DNV GL offshore standards,including documentation requirements, certification requirementsand material [ ]

5 Added separate qualifier for units with heading control,POSMOOR(HC). Also describing requirements to thrusterassisted mooring in more Table 2 Added more detailed requirements to lay out of thruster assistedmooring [ ]Deleted use of alternative standards as an acceptable approachfor obtaining class notation POSMOOR. POSMOOR classnotation shall only be based on this layout to allign with other DNV GL offshore standards,including documentation requirements, certification requirementsand material [ ] [ ]Updated to reflect outcome of NORMOOR [ ] [ ]Updated text for frequency domain and time domain analysiswith respect to extreme value prediction safety [ ]Updated the entire chapter to allign with output from [ ] [ ]Removed the material factor to be included in characteristicstrength of mooring [ ] [ ]

6 Updated safety factors based on output from NORMOOR based on output fromNORMOOR Table 7 Probability levels have been adjusted to reflect the new safetyfactor and outcome from NORMOOR correctionsIn addition to the above stated changes, editorial corrections may have been made. ContentsOffshore standards, DNVGL-OS-E301 . Edition July 2018 Page 5 Position mooringDNV GL ASCONTENTSC hanges 1 8 Section 1 81 93 Abbreviations and 2 Technical 1 Environmental conditions and 201 Environmental Environmental Vortex induced 48 Section 2 mooring system 503 Characteristic Partial safety factors and 605 Additional requirements for long term Fatigue limit Reliability 778 77 Section 3 Thruster assisted Available System 4 mooring Structural design and Fluke Plate Anchor ContentsOffshore standards, DNVGL-OS-E301 .

7 Edition July 2018 Page 6 Position mooringDNV GL AS6 Suction 917 Gravity mooring chain and 919 Steel wire Synthetic fibre Windlasses, winches and chain 9712 Winches for pull-in of mooring and riser mooring line monitoring Structural arrangement for mooring equipment for mobile Arrangement and devices for towing of mobile mooring line buoyancy 5 1161 Testing of mooring chain and 1162 Test of steel wire Test of windlass and winch and chain Test of manual and automatic remote thruster Testing of synthetic fibre Testing of mooring line buoyancy 118 Chapter 3 Certification and 1 Class Class notation 120 Section 2 Equipment selection and Specification of Classification requirements for Classification requirements for mooring Classification requirements for steel wire

8 Classification requirements for synthetic fibre Classification requirements for windlass , winches and chain Classification requirements for Classification requirements for mooring line buoyancy 14110 Classification requirements for arrangement and devices for Classification requirements for tension measuring Survey during ContentsOffshore standards, DNVGL-OS-E301 . Edition July 2018 Page 7 Position mooringDNV GL ASChanges 1 Section 1 Offshore standards, DNVGL-OS-E301 . Edition July 2018 Page 8 Position mooringDNV GL ASCHAPTER 1 INTRODUCTIONSECTION 1 GENERAL1 This offshore standard contains criteria, technical requirements and guidelines on design andconstruction of Position mooring systems, as well as technical requirement for mooring and The objective of this standard is to give a uniform level of safety for mooring systems, consisting ofchain, steel wire ropes and fibre The standard has been written in order to.

9 Give a uniform level of safety for mooring systems serve as a reference document in contractual matters between purchaser and contractor serve as a guideline for designers, purchasers and contractors specify procedures and requirements for mooring systems subject to DNV GL certification andclassification The standard is applicable to all types of floating offshore units, including loading buoys, and coversthe following mooring system components: stud chain studless chain Kenter shackles, D-shackles with dimension according to ISO 1704 LTM shackles suction-friction components purpose built connection elements buoyancy and weight elements steel wire ropes fibre ropes windlass , winch and stopper fairleads anchors This standard includes prescriptive requirements based on existing technology and note:For complex or non-standard applications, see DNVGL-OS-A101 [ ].

10 ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t -e---Chapter 1 Section 1 Offshore standards, DNVGL-OS-E301 . Edition July 2018 Page 9 Position mooringDNV GL Prescriptive requirements are not intended to inhibit the development and application of newtechnology and operations, and available technological and technical improvements at the time of applicationshould be taken into of novel technology or designs shall be preceded by a recognised qualification as described in For application of this standard as technical basis for classification see The standard is applicable for and limited to column-stabilised units, ship-shaped units single pointmoorings, loading buoys and deep draught floaters (DDF)