phase 4 report - DNV

RN02: DESIGN OF FLOATING STRUCTURES IN ICE // PART 4 ANNEX ABarents 2020Whenever possible, the friction tests are carried out at the same time as the model tests to maintain the same icestrength.A.17 Ice managementA.17.1 GeneralFloating structures that are deployed in ice-covered waters are often supported by highly capable ice managementvessels, with the intended role of modifying the local ice environment, reducing ice actions on the structureand enhancing ice clearance around it. The requirement to identify potentially adverse ice features or situationsrequiring ice management and then to deal with them in a timely manner increases the range of environmentalconsiderations that are normally associated with fixed structures. Fixed structures can also rely on icemanagement to ensure access to re-supply and offloading facilities and to clear potential escape routes for EERcraft.The type of ice management systems that is employed can have a significant influence on the design approachtaken for any particular offshore system. This depends upon expected level of ice management reliability, forexample, the ability to consistently detect potentially adverse ice conditions and, in turn, to manage themsuccessfully before they interact with the structure (e.g. by towing icebergs, clearing grounded ice from EERaccess points, fragmenting severe sea ice features, etc.).The major components of an ice management system used for floating facilities in ice-prone regions are illustratedin Figure A.17-1. In the outermost region or observation zone, ice features are detected using a variety oftechniques, including aerial surveillance (visual or radar) and satellite-based radar or optical systems. Potentiallyhazardous features such as icebergs, multi-year and thick ice floes, ridges or rubble fields are tracked and theirmotion forecast according to the requirements of the structure and its operation.Figure A.17-1 – Typical components of an ice management systemReport no 2012-0690 99