Abstract
While sailing in head or bow quartering seas operators on board of small planing boats try to avoid unacceptably large vertical peak accelerations, the main limiting factor for operability, by temporary speed reductions. The operators observe the incoming wave, roughly estimate whether or not the next impact might be too severe, and if so, they choose a certain amount of thrust reduction. Results of full scale trials suggested that an increase of operability may be realised using this so-called thrust control.
In this paper the concept of smart control for small planing monohulls sailing in head seas has been introduced. The idea of smart control is that a solution for the increase of the operability of small planing monohulls may be found by using automated proactive control of the thrust. The main purpose of smart control is to keep the vertical accelerations below a predefined threshold value while striving at the highest possible average forward speed during a trip. Three elements are essential for such a control system: a shipboard wave measurement system, a computational model that predicts the response and a stable control system for the thrust.