Stefanowski, Andrzej; Zwierzewicz, Zenon
(Scientific Journals of the Maritime University of Szczecin, Zeszyty Naukowe Akademii Morskiej w Szczecinie,
2012)
This paper presents observations and remarks on the work of ship's steering gear controlled by the autopilot in high seas. Attention is drawn to the insufficient power of steering gear operated by the autopilot in high waves and the consequent possibility of overloading and damage to the gear, creating a threat to the ship. Standard safeguards against damage are discussed. It is suggested that the alarm system should be extended to indicate the load of steering gears. The authors propose a method for assessment of the steering gear load by using a signal that is a nonlinear function of the actual rudder angle, based on the solution used in TS-type autopilot adaptation blocks. The results of computer simulations to obtain such signals for autopilot-controlled ship movement in irregular waves (sea state ranging from 3 to 6) are presented. The conclusion reached is that the signal can be used to assess the steering gear load, which may contribute to increasing ship’s safety in high sea states