Dynamic Positioning Calculations

The Dynamic Positioning module determines a static balance between steady environmental forces and available thrust and rudder units on the vessel. Each option determines the solution of:

Details of the environmental forces due to wind (W), current (C) and wave-drift effects () are given in Environmental Effects. The procedure of allocating thrust forces, directions and rudder angles is described in Thruster Allocation Logic, and Representation of a Fixed Propeller and Rudder describes the algorithms which are used for including a rudder and fixed propeller.

The solution of equations (70) is obtained directly for option THRUST, since fixed environmental forces are supplied and the thrust forces are determined to give a balance. No rudder effects can be included in this option. The solution is iterative for options ENVIRO and ERN since a limiting thrust magnitude is specified and the maximum environmental magnitude in which a static balance is possible needs to be determined iteratively.