Applying the DOE toolkit on a Lean-and-Green Six Sigma Maritime-Operation Improvement Project

摘要

Purpose - The purpose of this paper is to provide a case study on endorsing process improvement in maritime operations by implementing design of experiments on Lean Six Sigma performance responses. It is demonstrated how process efficiency and environmental muda may be dealt with simultaneously in a lean-and-green project driven by hardcore Six Sigma tools. Design/methodology/approach - A 16-run Taguchi-type orthogonal design was employed to gather data for vessel speed (VS), exhaust gas temperature (EGT) and fuel consumption (FC) as modulated by a total of 15 controlling parameters synchronously. Active dependencies were inferred based on the desirability analysis method on direct process data from a performance log. This log was maintained for a long-term monitoring during sea voyages of a double skin bulk carrier of 55,000 DWT while in sea service. Findings - A high composite desirability value was achieved eclipsing the 0.90 mark. Values well over the 0.9 level were also obtained for the three examined individual desirability values of VS, EGT and FC. Leading controlling parameters were discovered to be compressor pressure, fuel pump index, slip, governor index and MIP. Practical implications - A Lean Six Sigma project is carried out to improve performance characteristics in ordinary maritime operations. While the company in the case study outlined in this article no longer relies on periodic inspections to determine machinery conditions, improvement on key process characteristics were nevertheless deemed worthy of ameliorating. Information retrieval from computerized continuous monitoring systems assisted in conducting experimental designs in order to obtain optimal performance. Specifically, the tuning of vessel main engine running mode was examined aiming at increasing the quality levels of output power to the shaft along with a reduction of NOx emissions. Originality/value - This work adds an interesting paradigm in the critical field of maritime activities for processes in full gear while operating at sea. Maritime operations are an imperative necessity when expediting international trading transactions. It is the first time that such a case study has emanated from a real pilot Lean Six Sigma project which interlaces process efficiency enhancement with concurrent environmental muda reduction.