amics revealed
Captain interviews In parallel, interviews with captains of ice going vessels were done to map the major risks and challenges that are perceived and experienced by the individual operators. This helped gain insight from those with direct experience of ice operations in Russia, Finland, Sweden, the USA and the UK.
Typical topics of interest concerned the main risk elements such as voyage planning and preparation, which ship type and Ice Class is required but also the development of operational procedures for manoeuvres when operating in ice. Navigation in ice requires up-to-date information about the ice conditions, such as ice thickness and ice coverage. Modern ice-cover prediction systems, combined with satellite recordings, meteorological and oceanographic predic- tion models, enable optimal route planning in ice-covered regions.
The work of the PROPOLAR group is almost finished. The lessons learnt are implemented in daily routines and used to enhance research in the field of the scalability of ice failure mechanisms, as well as for the understanding of the fundamental physics of ice loads on propellers.
and operating of azimuthing propulsors in ice need to be better understood. At this moment, only a limited number of publica- tions are available which relate to ice loads on an azimuthing propulsor, particularly when it comes to the pod housing.
In a bid to develop an analytical model to determine the ice loads on podded propul- sors, analytical models based on the latest rules described in IACS were used. Formu- lations for PODs were derived by using the scarce full-scale data available. The selected methods were coupled with the use of more detailed measurements. Naturally, it would be preferable to do these measurements at full scale but due to limitations and con-
straints, this is rarely achievable but model tests represent an attractive alternative. However, measuring ice impacts at model scale faces some specific challenges. To determine the ice loads on a propeller, a model test setup was designed capable of measuring the highly dynamic forces and torque in all directions. This setup has been extensively calibrated and tested in con- trolled conditions. Finally, the setup was used for actual ice impact measurements in cooperation with AARC of Helsinki. The AARC hi-tech ice tank was used to measure propeller-ice impacts including synchronised, high-speed video recordings, which gave a unique insight into the propeller ice contact and the corresponding loads.
Modelled ice ridge seen from below
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