Combination of navigational and VDRbased information to enhance alert management

ABSTRACT: Within this paper results of ongoing investigations will be presented. Main subject of studies is laid on the present situation of alert management onboard ships navigational bridges and potential use of data recorded with mandatory ship-borne VDR equipment during normal ship operation to support the process of on board collision avoidance. The investigations and results discussed and presented in the paper are gained within trhe work in two different projects on research and technical development

Iceberg scouring and sea bed morphology on the eastern Weddell Sea shelf, Antarctica

A detailed shallow seismic and side scan sonar study, combined with vibrocoring on the continental shelf off Riiser Larsenisen ice shelf, East Antarctica, has provided information on the different morphological patterns present in the area. Features related to the motion of grounded icebergs prevail, with relatively narrow iceberg plough marks being predominant. A‘washboard pattern’probably results from a wobbling motion of grounded, tabular icebergs under influence of direct push by the advancing ice shelf, and a hummocky disturbed sea bed morphology results from small scale sediment slumping, often triggered by iceberg action. Narrow, elongate depressions incise the sea floor sediments, which are composed of glacigenic diamictons. Formation of the depressions is not fully understood, but erosion by subglacial meltwater under an expanded East Antarctic ice sheet is a possibility, although this requires a different glacier thermal regime than that of the present-day. Although this study is restricted in area, the processes of the region are typical of the Antarctic continental shelf. The results may hence have a more regional significance