Exam Question

An oil tanker 160m long and 22m beam floats at a draught of 9m in seawater. Cw is 0.865. The midship section is in the form of a rectangle with 1.2m radius at the bilges. A midship tank 10.5m long has twin longitudinal bulkheads and contains oil of 1.4m3/t to a depth of 11.5m. The tank is holed to the sea for the whole of its transverse section. Find the new draught.