SAFEICE - Increasing the Safety of Icebound Shipping
Overview
Background & policy context:
International trade and the transportation of oil are making Europe's northern waterways - many of them narrow and iced over in winter - increasingly hectic hives of activity. At the same time, the Arctic represents an extremely fragile environment, making the prospect of maritime accidents potentially devastating to local ecosystems and hugely expensive to clean up.
Objectives:
- Decrease the environmental and material risks to shipping in ice covered waters by creating a unified basis for winter navigation system for first year ice conditions including the methods to get the required ice class;
- Develop semi-empirical methods based on measurements and advanced theoretical models to determine the ice loads on ship hull and relate these to the operational scenarios and the ice conditions;
- Develop ship-ice interaction models and stochastic models to assess the design loads on ship hull. The outcome is a description of the ice load versus ice and operational parameters;
- Create a framework to develop design codes and regulations for plastic design basis for icebound ships.
Methodology:
The SAFEICE project's aim was to create a scientific basis for ice class rules (ship hull strength) and for placing requirements on ice classes. The main purposes in the SAFEICE project were to develop semi-empirical methods based on measurements to determine the ice loads on ship hull, to find relationship between operational conditions and ice load, to develop ship-ice interaction models to assess the design ice loads on ship hull, to develop methods to estimate ultimate strength of shell plating and frames and to develop methods to analyse ice damages.
The target was to decrease the risk involved in winter navigation. Baltic Sea, Okhostk Sea and Canadian waters were used as validation areas for ice load predictions. The aims were achieved by compiling a database of earlier information on ice loads and ice pressures. This was a collection of full scale ice load data measured on board ships of various types sailing in different sea areas. Ice load data sets are used in validation of deterministic ice load models. The ice loading process has a stochastic nature. The stochasticity of ice loads influences the design ice load value.
In the SAFEICE project probability based methods in ice load evaluation were developed and validated with measured data. First yield load of ships operating in the Baltic Sea were often exceeded. However, serious ice damages were rare. Ultimate load carrying capacity of hull structure was therefore utilised. Instead of elastic design, ice rules could be based on plastic design. Probability of loads exceeding ultimate strength of various structural elements could then be estimated and the design load level will be explicitly determined.
The project was carried out with the participation of universities, maritime authorities and European, Canadian and Japanese marine research institutes. The partners represented the vertical chain from basic research into implementing the ice rules and enforcing safety at sea.
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