Vessel’s speed optimization versus fuel and freight cost ratio

This study proposes a simple methodology for determining the economic average vessel speed, taking into account only two main parameters that most significantly affect the transportation cost: the fuel price and the freight cost. According to the authors, this approach allows to determine the optimal vessel speed at the stage of voyage planning and requires the crew to ensure the average speed for voyage, which is much easier under constantly changing meteorological conditions than to provide a series of specified speeds. The proposed method for determining the optimal (in terms of minimizing transportation costs) average vessel speed was applied for a gas tanker with a deadweight of 85513 tons and a main engine with a capacity of 27480 kW. From the analysis of the given example, it follows that, contrary to popular belief, a decrease in the vessel speed does not always lead to a decrease in the transportation cost. For vessels using LNG as the main engine, at the current gas prices, the freight cost may be the determining factor in the cost of transportation.