USA as Represented by Secretary of the Navy

Max D Weber

Steven F Naud

J Dexter Bird, Iii

Lei Lani Lucero

Martin D Fink

Christoph Hyder

A method is provided for quantifying design parameters for a moving mass ship roll stimulation system given a maximum angle of roll &thgr; to be induced for a ship, a righting moment R per degree of list for the ship, a natural roll period T , a damping ratio &zgr; for the ship and a center of gravity for the ship. A total induced moment expression at the natural roll period T is determined for the moving mass ship roll stimulation system as a function of a plurality of design parameters therefor. The total induced moment expression is equated to 2&zgr;&thgr; R and values for the design parameters are selected to satisfy the equality.

Method for quantifying design parameters for a ship roll stimulation system

A method and system are provided for reducing sea state induced vertical motion of a shipboard crane's load. Sea state induced vertical velocity of the crane's suspended load is determined as a function of: i) the horizontal radial distance the load extends from the crane's axis of rotation, and ii) motion of the ship at the crane's axis of rotation. The load is then moved vertically at a speed that is defined as being equal to the vertical velocity in a direction that is opposite that of the vertical velocity.

Vertical motion compensation for a crane's load

A method is provided to automatically control a cranes's rider block lifte and taglines. Current position of the crane's rider block is determined in terms of its horizontal and vertical coordinates, as well as in terms of the inhaul angle of the liftline. A matrix is then generated that defines i) incremental change in the rider block's horizontal coordinate with respect to incremental change in each of the boom angle, a length of the liftline and a length of the taglines, ii) incremental change in the vertical coordinate with respect to incremental change in each of the boom angle and lengths of the liftline and taglines, and iii) incremental change in the sine of the inhaul angle with respect to incremental change in each of the boom angle and lengths of the liftline and taglines. A vector defining velocity criteria for the rider block is provided. The velocity criteria is defined in terms of horizontal motion of the rider block, vertical motion of the rider block and rate of change of the inhaul angle. The velocity criteria vector is multiplied by an inversion of the matrix to generate a control matrix that defines speed and direction of travel for the liftline and taglines. Movement of the liftline and taglines is controlled using the control matrix.

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Panama City Beach, FL, United States of America

Max D Weber