Smart control of fast ships – Part 2: A conceptual model of automated proactive thrust control

Abstract

A planing monohull sailing in head seas experiences large vertical accelerations, which are considered to be the main limiting factor for operability. Results of full scale trials (Part 1) showed that the operability of a small planing monohull sailing in head seas may be increased when the helmsman actively controls the thrust.

In the present paper a conceptual model of automated proactive thrust control, or smart control, is presented. The response of a small planing monohull sailing in head seas has been mimicked using an elementary model. The essential hydromechanic aspects are incorporated. A control system for the thrust has been included. The response will be predicted continuously and if necessary, an appropriate amount of thrust reduction will be applied. By temporary speed reductions the magnitude of the next occurring vertical peak acceleration is reduced.

Results generated using this conceptual model show that the operability may be increased using automated proactive thrust control if sufficient time to decelerate to a sufficiently low speed before impact is available. This is provided that the vertical peak accelerations are estimated accurately.