A ship will be subjected to the comprehensive effect of dynamic load, static load and sudden load (such as collision load) during the operation, resulting in the extremely complicated force distribution of the saddle of the LNG fuel tank. The determination of the force distribution of the saddle is therefore critical for the design and installation of the saddle of the LNG fuel tank. A calculation method for the saddle load superposition has been proposed by studying of the force between the C-type independent fuel tank and the saddle for the dual fuel ships, combing of IGF rules and the "Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk" of CCS. This method solves the design problem of the saddle and the surrounding structure. The key points for installation are given to provide technical references for the design and the installation of this type of spherical tank's saddle.

During the vibration measurement of the 61 000 t Bulk Carrier in a sea trial, it was observed that the longitudinal vibration of the accommodation area was very serious with a speed of 91 min/s for the main engine. The reason causing the abnormal structural vibration in accommodation area has been found according to the theory of the finite element modal analysis of the hull structure, combined with the vibration analysis of the local structure and the judgment of the main excitation source. The vibration problem of the accommodation area is then solved by adjusting the ballast water. Finally, the finite element calculation and on the board measurement are carried out for the validation. The calculation and measurement results meet the ISO 6954 vibration standard required by the technical specification. It can provide technical reference for the design and operation of the ship type.