MARPOL Annex VI states one parameter for calculating the EEDI of a ship’s speed in calm sea conditions based on speed trial results. To eliminate the effects of external factors during a sea trial (wind, waves, current, water depth, sea temperature) and provide a way to calculate and analyze a ship’s speed in calm sea conditions, the IMO assigned two methods in its Guidelines (2014 Guidelines on survey and certification of the Energy Efficiency Design Index (EEDI)); those were ISO 15016:2015 and ITTC 2014 Guidelines. However, at MEPC 73 (October 2018), the IMO Guidelines were revised to require compliance with either ISO 15016:2015 or the ITTC 2017 Guidelines.
 
ClassNK has provided shipyards, and the greater maritime industry with “PrimeShip-GREEN/ProSTA” as a support tool since 2015 for calculating a ship’s speed in compliance with ISO 15016:2015. To further contribute and provide technical support regarding ITTC 2017 Guidelines, ClassNK has newly developed “PrimeShip-GREEN/ProSTA ver.ITTC” which has the same user-friendly interface as the former “PrimeShip-GREEN/ProSTA” and calculates a ship’s speed in accordance with ITTC 2017 Guidelines.
 
In addition, to continue providing technical support regarding ISO 15016:2015, the Society also released “PrimeShip-GREEN/ProSTA ver.ISO” which adds more functions to the former “PrimeShip-GREEN/ProSTA”.
 
Details on “PrimeShip-GREEN/ProSTA ver.ITTC” and “PrimeShip-GREEN/ProSTA ver.ISO”, can be found at the following website:
http://www.classnk.or.jp/hp/en/activities/primeship/index.html