When calculated as described in Current and Wind Hull Drag, the wind and current loads have no dependence on yaw rotational velocity. This contribution is calculated separately and the yaw rate drag moment is given by [44]:

(7–15)

where is the yaw rate drag coefficient which is force per unit length per unit velocity squared, is the relative heading angle between current or wind propagating direction and the analyzed structure as shown in Figure 7.1: Relative Directional Angle Between Current/Wind and Structure, and are the relative current velocity components in the structure local x- and y-axes respectively. The integration is along the length of the structure between and in the structure local axis frame Gxyz.

If the center of gravity is not at the geometric center of the structure's projection on the water surface, the yaw rate drag will have a lateral component given by a very similar expression:

(7–16)