Ship propulsion system BIMS®

with dynamic positioning function

Improvement of AP-/DP- and manoeuvring performance by rudder force measurement System advantages: Reliable and safe dynamic positioning/manoeuvring operations Less rudder motion in DP and AP mode Energy savings through improved efficiency Elimination of aft tunnel thrusters on a case-by-case basis Emission reduction “Quieter” rudder system Reduced manoeuvring response times Significantly less rudder motion Reduced waste and maintenance costs Computerised manoeuvring operations today Modern dynamic positioning systems (DP) and auto-pilot systems (AP) utilise a variety of input signals to maintain course or position, e.g. from positioning reference sensors, combined with wind sensors, motion sensors, gyro compasses, GPS data, etc. These data are processed by an IT system to allow the course or drift to be predicted and to calculate countermeasures controlling the actuators in the vessel’s propulsion system. Input data and processing is of high quality, but only reflects the vessel’s motion response. Inertia causes a massive decrease in the strength of these control signal, which do not meet or provide sufficient quality for manoeuvring. For rudder-propeller arrangements relatively high corrections were applied to rudder angle, resulting in the generation of high rudder forces. The vessel turns more than necessary for the predicted course correction, resulting in a similar counter-action in the opposite direction. This effect results in hysteresis, or rudder flipping, causing the steering gear to work continuously and more or less strong fluctuations around a set course or position.