To help reduce downtime and improve vessel station-keeping in ice, CARD proposes to model ice loads in the design of moored and dynamically positioned (DP) systems, selecting a small number of particular locations for study, and to implement the results in order to determine mooring loads and study DP systems, both selected in consultation with the Industry Advisory Committee. Moored vessels operating in ice will need to be able to disconnect under high ice loads, and floating systems must be evaluated in terms of feasibility and cost. Detailed understanding of ice conditions, ice mechanics and loading, ice management and the response of floating systems are necessary inputs in the development of station-keeping solutions for ice environments.
Key research topics identified for CARD’s Station-Keeping program include:
Scale-Model Testing of Floating Systems
Fundamental questions remain regarding the scaling of results from model ice basins to predict full-scale behavior. For issues such as the prediction of loads, ice clearing and ice accumulation for vessels operating in ice, research is needed to evaluate and improve methodology and scaling of results for scale-models of floating structures. Scale-model testing of ice-induced loads on mooring systems and dynamically positioned floating systems have been identified as areas for further research.
Modelling of Loads on Moored Floating Platforms
Modelling ice-induced loads on mooring systems for different loading scenarios, ice features, types of ice, metocean conditions, vessel designs, anchor systems and mooring configurations is needed. To aid in the assessment of mooring loads used in design of systems for selected development concepts and locations, probabilistic models must be developed. Research is also needed to improve understanding of issues associated with the disconnection of turrets under high ice loads, reconnection of mooring in ice conditions, or interactions of individual mooring lines with ice features.
Modelling of Loads on Dynamically Position Platforms
The response of DP systems to loads from managed and unmanaged ice is complex and at present is not well understood. To improve understanding of such systems, models of ice-induced loads and dynamic positioning system response for different loading scenarios, ice features, types of ice, metocean conditions, vessel designs and DP system configurations are needed. The development of a probabilistic framework for studying and evaluating DP system response has been identified as an area for further research.
Concept Evaluation and Downtime Reduction Tools
To aid in the evaluation of different floating system concepts for a range of environmental conditions and design configurations, new tools will be developed. This includes decision-support tools to assess expected downtime for different design concepts, which will help assess the required number and types of support vessels, and the optimal platform concept to reduce operational downtime.