Patent ID: 6026759
Filing Date: 2000-02-22
Classification: B63B,B63H

Abstract:
The method of controlling average list about its roll axis of a forward-moving powerboat capable of speeds in excess of about 20 kilometers per hour and of an overall length generally under about 25 meters and having a driving and steering unit, the method comprising the steps of:providing a small fin-rudder located under a forward portion of the powerboat's keel,mounting said fin-rudder to a rotatable shaft extending upwardly into the powerboat and capable of rotating said fin-rudder about an upwardly extending longitudinal axis of said shaft a maximum of about thirty degrees clockwise or counterclockwise as seen from above on either side of a neutral position, said neutral position being said fin-rudder's fore and aft alignment with said keel,thereby providing a range of adjustment of an angle-of-attack of said fin-rudder between about 30.degree. clockwise and about 30.degree. counterclockwise relative to oncoming water resulting from forward moving of the powerboat,for altering toward port an average list of the forward-moving powerboat about its roll axis as seen from astern of the powerboat adjusting the angle-of-attack of said fin-rudder in the clockwise direction for exerting a steering force toward starboard while also exerting on the forward-moving powerboat a counterclockwise banking force around its roll axis as seen from astern,substantially simultaneously with adjusting in the clockwise direction the angle-of-attack of said fin-rudder also adjusting in the clockwise direction as seen from above the direction of thrust of the powerboat's driving and steering unit for exerting a steering force toward port to counteract the steering force toward starboard being exerted by the clockwise adjusted angle-of-attack of said fin-rudder for maintaining the powerboat's heading, andutilizing a counterclockwise banking force around the forward-moving powerboat's roll axis as seen from astern resulting from the clockwise adjusted direction of the direction of thrust of the powerboat's driving and steering unit acting in cooperation with the aforesaid counterclockwise banking force around the powerboat's roll axis being exerted by the clockwise adjusted angle-of-attack of said fin-rudder for altering toward port the average list of the forward-moving powerboat around its roll axis while maintaining the powerboat's heading; andvice versa for altering toward starboard an average list of the forward-moving powerboat about its roll axis as seen from astern of the powerboat,whereby steering forces in opposite directions being exerted by the angle-of-attack of the fin-rudder and being exerted by the thrust direction of the driving and steering unit counteract each other for maintaining the powerboat's heading, andwhereby banking forces in the same direction around the roll axis of the powerboat being exerted by the angle-of-attack of the fin-rudder and also being exerted by the thrust direction of the driving and steering unit act in cooperative additive relation for controlling the average list of the powerboat about its roll axis as seen from astern.