Semi-submersible tanker with directional ice cutters - has bridge connected to hull by rotatable shaft that can align cutters with encroaching ice

摘要

Tanker has a submersible hull with a mast extending above it supporting a bridge section. The base of the mast is journalled in the hull for rotation about a vertical axis. The bridge section is rotatably supported on the mast. The mast can be driven relative to the hull and the bridge section so that the hull and bridge remain aligned whilst the angular position of the mast is changed. Rotary ice cutters are positioned along one side of the mast and are positioned relative to the surrounding ice by rotation of the mast so as to be aligned with the direction in which the ice encroaches on it. By being able to position the ice cutters between encroaching ice and the mast, the vessel is prevented from being forced off course by the ice moving across the intended direction of travel of the vessel.