Interval Planning Model For Dry Bulk Fleet Considering Specialized Ships And General-purpose Ships

At present,the shipping market has not yet emerged from a downturn,with overcapacity and market volatility,and shipping companies are facing enormous operational pressures.In order to better meet the challenges of the shipping market,timely and scientific fleet planning is essential.Affected by the large-scale and specialization of ships,most scholars are studying the fleet planning research,and the research objects are all special-purpose ships without considering the influence of general-purpose ships.This is inconsistent with the actual situation,especially In the dry bulk shipping market.Special-purpose ships and general-purpose ships have different characteristics in terms of cargoability,operational flexibility and economy in transporting bulk cargo.Special-purpose ships,such as iron ore ships,cement ships,sawdust boats,etc.,have poor suitability and can only transport specific types of goods,and have poor operational flexibility,but the economy of transportation is good;general-purpose ships are suitable for goods.Well,it can meet the transportation needs of a variety of goods,and the operation is flexible,but the economy of transporting certain types of goods is not as good as that of special-purpose ships.In the dry bulk shipping market,especially for large and medium-sized dry bulk shipping companies that operate more types of goods,how to determine the size of the dedicated and general fleet is an important decision-making issue in the shipping company fleet planning.In order to solve the problem of how large and medium-sized dry bulk shipping companies maintain the proportion of reasonable capacity of general-purpose ships and special-purpose ships,the fleet can effectively utilize the economies of scale of special-purpose ships and fully utilize the general-purpose ships to transport more This kind of cargo effectively responds to the impact of market demand fluctuations.This paper aims at minimizing fleet operating costs and establishing a dry bulk fleet interval planning model under demand fluctuations.And using genetic algorithm to solve,the calculation results show that under different fluctuations of demand,the general-purpose ship and special-purpose ship capacity maintain different proportional relationship.It can help to provide reference for ship type selection for shipping companies in fleet planning,improve fleet risk resistance and operational flexibility.