Comparison between Vessel’s Displacements Calculated by Bonjean Curves and Hydrostatic Curves

Hydrostatic Curves is widely used to calculate vessel’s displacement by ship’s officers and surveyors. However, under some specific circumstances such as light ballast arrival condition, it is difficult to obtain an accurate figure of displacement by using Hydrostatic curves. At this time, Bonjean curves as an alternative can be employed in calculating vessel’s displacement. The procedures are introduced step by step to calculate the vessel’s displacement by Bonjean’s curves. The differences of calculation by two means are demonstrated on a specific bulk carrier and therewith the reasons are analyzed. Finally, the article appeals the detailed Bonjean curves shall be provided on board by shipyard for improving the accuracy of calculation.