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Wednesday, September 30, 2020 

NYK Line and shipbuilder Japan Marine United Corporation (JMU) have agreed to introduce a new shipbuilding contract that guarantees propulsion performance in actual sea conditions.

According to the companies, shipbuilding contracts typically guarantee ship speed by confirming the relationship between ship speed and horsepower in calm sea conditions without waves. Mutual confirmation then occurs during the sea trials that are conducted during construction. However, calm voyages without wind and waves are rare during commercial voyages, and stormy weather conditions are often encountered. Therefore, it is generally the obligation of shipping companies to identify and procure ships that have good propulsion performance in actual weather conditions.  The propulsion performance in actual sea conditions in this case represents the "relationship between speed and metric horsepower in the actual sea service." Ships sailing in waves, which is an irregular phenomenon, require more horsepower to achieve the same speed than when sailing in calm waters due to hull shaking and increased resistance due to reflected waves. This is affected by various factors such as wind direction, wind speed, wave height, wave direction, wave period, tidal current, ship speed, ship type, displacement, and loading condition. Advanced technical capabilities are required for verification.

Recently, with the improvement of satellite communications at sea and the progress of IoT technology, it has become possible to efficiently collect a variety of useful data. NYK, which says it seeks to further differentiate itself from others in ship performance, and JMU, which seeks to demonstrate the superior performance clause in the shipbuilding contract, have agreed to the introduction of an 'actual sea' condition.

After a ship goes into service, performance data will be collected and verified to determine the performance guarantee, which will confirm the relationship between ship speed and horsepower under sea conditions that include wind and waves. In addition to this guarantee, NYK Line and JMU will implement a PDCA improvement process and jointly work on the construction of other ship types in the future. Through many years of joint research between NYK Line and JMU, in addition to a common understanding of data processing, storage, and analysis methods, the two companies have established a cycle of feedback on ship design to continually improve performance.

The partners plan to further develop this guarantee for verification of propulsion performance for many ship types, which is difficult to do in sea trials at the time of construction. Discussions with partner shipyards on the performance of vessels in the actual sea conditions will enable further improvements. By providing customers with well-performing vessels, environmental consciousness can be raised throughout the supply chain.

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