Surface bodies do not have a mass directly associated with them. In order to include the mass effects of a surface body, one or more point mass elements should be included.
To add a Point Mass element:
Select a Part in the tree view.
Right-click the Part and select Add > Point Mass, or click the Point Mass icon in the Parts toolbar.
Select the Point Mass object in the tree and set the properties manually, or select Program Controlled.
If Mass Definition is set to Manual, you must input all the properties for the point mass (Mass, X, Y, and Z Position coordinates)
Alternatively, if a Program Controlled point mass is used, the mass and the horizontal position are calculated from the panel elements and any manually-defined point masses, distributed masses, point buoyancies, or Line Bodies in the structure. The total structure mass equals the mass of water displaced, and the horizontal position of the Program Controlled point mass is calculated such that the structure center of gravity lies on the same vertical line as the center of buoyancy.
If the point mass is Program Controlled, its horizontal position and mass will not be displayed until a mesh has been generated; the Mass field will show an informational message Generate Mesh to Update.
The moments of inertia (or radii of gyration) and vertical position Z Position cannot be determined by the program and must always be input. Moments of inertia can be defined directly or by inputting radii of gyration. If Define Inertia Values By is set to via Radius of Gyration, you need to enter Kxx, Kyy, and Kzz. If you select Direct Input of Inertia, you must enter the Ixx, Iyy, and Izz values. The off-diagonal terms Ixy, Ixz, and Iyz may optionally be entered.
If the point mass is Program Controlled, the inertia properties which are not entered by the user will not be displayed until the Mass has been updated. For example: if Define Inertia Values By is set to Radius of Gyration, the inertia components Ixx, Iyy, and Izz will not be shown until the mass is determined.