The objective of this work is to develop representative glacial ice loads for the bergy bits and growlers that are hard to detect and present them in a form that is suitable for use in finite element analysis. In this paper bergy bit and growler sizes are estimated. Collision scenarios are examined for a typical Cape Class bulker of both conventional and icebreaking shape. These scenarios predict the maximum forces that occur for a range of ship speeds and impact locations along the ship. Time-histories are developed for a few selected loads. Pressure distributions are developed for the selected time-histories. These pressure distributions are suitable for FEA input and vary in magnitude over the contact area. The contact area also changes in size as the time history develops.
In order to predict performance of a bulker through glacial ice-infested waters, two aspects must be considered: the probability of encountering undetectable bergy bits and growlers in the transit path and the effects of impacting such ice formations at speed. This paper focuses on the glacial loads and developing pressure distributions within the loads.
It is reasonable to assume that large bergs will be detected and easily avoided; thus, striking these unexpectedly is not likely. It is the smaller, less detectable ice formations that pose the most risk. Consequently, determining the impact forces for a range of speeds for the growler or bergy bits that can unexpectedly (without prior detection) impact the ship is of greater importance. The World Meteorological Organization (WMO) has defined an extensive set of terms to classify all types of sea ice. Therefore, the likely place to encountered growlers and berg y bits is where there is ice bergs sighted.