A force of constant magnitude may be applied to any point on a structure by the addition of a Point Force object.
To add a Point Force:
Select the Hydrodynamic Response object in the tree view.
Right-click the Hydrodynamic Response object and select Insert > Point Force, or click the Point Force icon in the Analysis toolbar.
Point Forces can be applied to Stability Analyses, Frequency Statistical Analyses, and Time Response Analyses. A Point Force which has been added to a Stability Analysis can be Propagated to any downstream Frequency Statistical or Time Response Analyses.
Under the Point Force Force Definition, select Application Position from the drop-down menu of structure Connection Points. The Behavior of the Point Force can be set to either:
Direction is Constant: the position at which the force is applied moves with the structure, but the direction that the force acts in remains constant in the Fixed Reference Axes (FRA). This can be used to model the force of the wind acting on a vessel's superstructure, for example.
Direction Moves with Structure: both the position and direction of the force move with the structure (the direction that the force acts in remains constant in the Local Structure Axes (LSA)). This can be used to model a vessel's thruster, for example.
Under Application Definition, use the Defined By option to specify whether the Point Force is defined by:
Components: use the Component X, Component Y, and Component Z fields to set the individual force components in the Fixed Reference Axes (FRA).
Magnitude and Direction: specify the absolute Magnitude of the Point Force, and select a Fixed Point or Connection Point from the Direction Vertex drop-down menu to define the direction in which the force will initially act.