Mathematical Modeling of the Center Mass and Added Masses Variation of a Drilling Ship

The article is devoted to the construction of a mathematical model for changing the position of the center of mass and the attached masses of a drilling ship. The previously obtained equations of the drilling ship dynamics are not a mathematical model of a real ship. During the holding process over the drilling point, the drillship can have different dynamic models, characterizing its periods of operation: initial, preparatory, drilling, and final. During the lowering of the drill pipe and during the drilling process, its movement will affect the hydrodynamic characteristics of the vessel. In this case, the moments of inertia will be changed, primarily with respect to the selected coordinate axes due to the movement of vessel masses, the center of mass position of the of the drilling vessel, and the values of the added masses and moments. The mathematical model proposed in the article considers various modes when keeping a drilling vessel above the drilling point, since in the process of performing work, drilling equipment (drill pipes) are in various positions.