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Note: DYPOS

Abstract: Dynamic positioning (DP) is the capability of a vessel to automatically keep its position in open water by counteracting the environmental forces caused by wind, waves and current. Such systems are of growing importance. Both the accurate prediction of the limiting environmental conditions and the design of a DP-System for specified limits save costs due to the fact that the operating time of the vessel can be increased, anchoring becomes unnecessary and the use of expensive tugs is avoided. Typical applications of DP are offshore crane and jacking operations as well as virtual anchoring for passenger ships. To make a precise statement about the DP capability, a calculation method has been developed by the authors. The paper shows how the calculation of the DP capabilty is carried out by taking into consideration the interaction effects between the propulsion system and the hull as well as the environmental forces. To determine the interaction effects model tests were performed. The results are also presented in this paper and allow a more precise statement about these effects.