Automatic Stowage of Bulk Carrier Based on Ship Floating-State Control

The quality of stowage plan affects several aspects of ship security, including intact stability and structural strength. This study focuses on optimization of the stowage plan under a given floating state (i.e., the final heel and trim angle). The mathematical model for automatic stowage plan is built by using the following objectives: minimizing the total ballast water, maximum shear force (SF), and bending moment (BM), and maximizing the total cargo. The related safety assessment criteria, the final heel and trim angle, maximum tank capacity, and amount of cargo are considered as constraints. A two-layer optimization method based on differential evolution algorithm is proposed to solve the constrained optimization problem. According to the characteristics of bulk carriers, a simplified matrix method for engineering applications is discussed based on Newton’s iteration method to calculate ship floatation. To improve the calculation accuracy of SF and BM, a method based on the stereolithography model is proposed. Finally, an actual case of a 38,500-dead weight tonnage (DWT) bulk carrier is used to illustrate the effectiveness of the proposed approach.