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SAFEICE
Increasing the Safety of Icebound Shipping

SAFEICE aims to create a scientific basis for ice class rules (ship-hull strength) and for placing requirements on ice classes. The project will be carried out with the participation of universities, maritime authorities and European, Canadian and Japanese marine research institutes. The partners represent the vertical chain from basic research into implementing the ice rules and enforcing safety at sea.

Tags: Water

Background

The ice cover present on many northern sea areas poses many difficulties for shipping. The sea ice creates a much higher resistance to motion than that encountered in open water. Thus the ships navigating in ice must have a much higher performance level (propulsion power, manoeuvrability) than ships navigating only in open water. Ice also causes high loads on the ship hull and machinery – much higher than those encountered in open water. The ultimate result of the ice load may be a rupture of the ship’s hull leading to an environmental accident or, at worst, a total loss. The winter of 2003 in the Baltic was more severe than a long-term average winter – and definitely more severe than the previous ten winters – and many ship damages and minor accidents occurred, for example the collision of two ships, due to ice. Propellers and rudders were damaged and several cases of severe damage on ships’ hulls occurred – some of these resulted in the hulls being ruptured. The present project is concerned with the ice loads and safety of ships in ice, but also in the terms of how a better performance in ice can reduce the risks.

The design of ice-strengthened tonnage is controlled by ice rules. For the Baltic and more generally for sea areas where only first year ice exists, the Finnish-Swedish ice class rules are applied widely. Most classification societies have also adopted these as their Baltic ice class rules.

Objectives

The basis for the required ice class is not clearly defined. This leads to confusion and a potential hazard for the safety of shipping, as experience from the Baltic shows when non-ice-strengthened vessels were allowed to enter the eastern Gulf of Finland through heavy ice.

The randomness of ice loads means that some way to treat the design question must be developed (as stated above). The irregularity of ice loads also has an implication on the design point.

The project aims can be summarised as:

  • decreasing the environmental and material risks of 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.
  • developing semi-empirical methods based on measurements and advanced theoretical models to determine the ice loads on ship hulls and relate these to the operational scenarios and ice conditions.
  • developing ship-ice interaction models and stochastic methods to assess the design loads on the ship’s hull.

The outcome is a description of load level versus ice and operational parameters.

  • creating a framework to develop design codes and regulations for a plastic design basis for icebound ships.
Ship in compressive ice in the Baltic Sea
Ship in compressive ice in the Baltic Sea
Helsinki University of Technology

Description of work

The first step in the SAFEICE project is to bring together earlier ice load measurement results. Analysis of these results will give an idea of the design for the ice-load level of different ships in different sea areas. The measured data will be arranged into a common database. The database will be designed so that different measurements are comparable with each other and that results from different ships can be combined. The analysis of different data sets gives a picture of data gaps that each measurement contains and those that need to be covered with additional measurements in certain sea areas or in certain ice conditions in the future. With an increased knowledge of the ice loading process it is possible to conduct better-arranged measurements and more realistic ice-load models. The data and load prediction tools can be used for validation of theoretical ice-load calculation models. Based on the analysis and database it is possible to develop theoretical and statistical models from ice-load calculations. These results can be then used when load responses are calculated. As a result, the risk level of ice damage can be estimated. The acceptable risk level is then defined by society and can be implemented into ship design, for example, via ice class rules.

Results

The extensive compiled database of ice loads and ice damages worldwide enable reliable verification of the developed ice load calculation models and can also be used in the future for similar purposes. This is the first time in the history of ice research that the expensive full-scale data from EU-countries (Finland, Sweden, Germany), Japan and Canada have been combined into a common resource.

Conducted model scale tests of ice navigation and related ice loads enable comparison of the loads on a conventional size and large ice-strengthened tanker and give valuable data for the development of future ice class rules for the Baltic Sea, especially to determine proper ice load levels for the large tankers navigating more frequently to Russian ports within the Gulf of Finland

Based on the data from full scale and model testing, analysis of the ice damages on the hull and extensive theoretical modelling of ice-induced load a synthesis has been developed for a good design basis for ice-strengthened ships navigating in the Baltic Sea. This will form the starting point for the development of the new ice rules for Baltic Sea, this work will be initiated by Finnish and Swedish Maritime Administrations in early 2007.

The systematic analysis of the risks related to the ships navigating in ice enable guidelines development for safe ice operation practises including both icebreaker and assisted ice strengthened ships operation principles. This can be use e.g. to educate future officers onboard ships navigating in ice in the Baltic Sea.

The wide Safeice colaboration between almost all nations operating ships in ice works toward a common understanding of these conditions and perhaps an eventual vision for a unified international ice classification standard.

A second ship in compressive ice in the Baltic Sea
A second ship in compressive ice in the Baltic Sea
Finstaship

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