Effect of Loading and Unloading Heavy Cargo on a Heavy-lift Ship Stability

The problems such as decrease of ship stability and transverse inclination are bound to be generated during the loading and unloading of cargo. In order to solve this problem, this paper takes the “Influence of Loading and Unloading Heavy Cargo on the Ship Stability” as the topic, and makes a deep research. First, it expounds the relevant concepts involved in the transportation of heavy goods in detail. Then, based on the theory of ship statics and comparing with previous research results, this paper summarizes and compares the ship stability calculation methods of loading and unloading, and proposes a general calculation method for ship stability, based on which it deduces the calculation method of ship's initial stability height and transverse inclination angle of the ship's heavy lifting considering the change of boom elevation when loading and unloading the heavy cargo. On the basis of this method, this paper analyzes the basic factors that affect the ship stability and the transverse inclination during the loading and unloading of heavy cargoes, and puts forward the specific method to adjust the transverse inclination. Finally, it verifies the above method taking “M/V Dafu” as a calculation example. Apparently, it can be seen from the calculation results that the calculation precision has reached the actual production requirement, and the change of the ship's initial stability is only related to the elevation angle of the boom. Thus, the transverse inclination of ship caused by loading and unloading of the heavy cargo can be adjusted by the allocation of ballast water.