AN INTEGRATED SHIP CONTROL SYSTEM FOR CS MANCHESTER CHALLENGE

The interactive nature of a ship in response to helm or fin stabilisers is well known and may be used to advantage to obtain roll stabilisation from the rudder. This paper describes a theoretical investigation, based on the container ship Manchester Challenge, to assess the benefits to be obtained from a fully decoupled controller; this is a controller which results in a non-interacting response of the ship, rudder exciting yaw motion only, and stabilisers controlling roll only. The method by which the controller may be synthesised is described and its implementation is discussed. A recursive equation is also developed for one of the matrix elements to demonstrate how such a controller may be realised digitally. A normal ship autopilot is included and ship yaw transient and harmonic responses are compared, with and without the decoupling system. This process is repeated for the ship roll characteristics considering a standard fin control strategy. In the case of this ship considerable advantages appear to have been obtained by adopting an integrated ship control system, both in coursekeeping and seakeeping. Order from BSRA as No. 51,933.