ClassNK Releases New Guidelines and Software for Container Carrier Structures. ClassNK has released a new revised edition of its “Guidelines for Container Carrier Structures – Guidelines for Direct Strength Analysis”, as well as a new version of its PrimeShip-HULL(DSA) software for use in designing container carriers in line with the new guidelines. ClassNK released the first edition of its “Guidelines for Container Carrier Structures” in 2003, providing shipbuilders and designers with a wealth of information on ship performance that the Society had accumulated over its many years in ship classification, as well as the latest information on new technologies and other advances related to container carrier construction.