Optimum speed analysis for large containerships

During these times of fluctuating freight rates and oversupply, selection of optimum speed will give an operator a crucial advantage. Until the recession, the emphasis has always been on larger capacity and higher speed. Now, design innovation and slow steaming are becoming important and this article details new software, which is set up to assist the speed optimization process for large container ships. The software uses both propulsion and revenue-cost analysis with an ultralarge container ship model of 20,000 20-ft.unit (TEU) as a case study to derive the most profitable speed. Shippers' costs are also estimated to assess the impact on shippers. This software can be used for new construction or existing ships. The results show that 19.5 knots is the optimum speed, which is a departure from the current trend of 25 knots but supporting the concept of slow steaming. The results are validated by Det Norske Veritas container cost models. Besides that, the multivariable nature of the optimum speed problem is discussed and further analysis has been carried out to determine the range of fuel cost, freight rate, and load factor in which this optimum speed is applicable (in this case, $1100/TEU < freight rate < $1300/TEU, $650/MT < fuel cost < $750/MT and load factor = 40%). This will be useful to ship operators for forecasting purposes.