GB821138A - - Google Patents

Abstract

821,138. Automatic ship stabilization systems. MUIRHEAD & CO. Ltd. Dec. 11, 1956 [Dec. 22, 1955], No. 36815/55. Class 38 (4). [Also in Group XXXIII] A ship is stabilized to its mean angle of list by stabilizers which are automatically controlled in accordance with a signal dependent on instantaneous angle of list modified by a signal dependent on mean angle of list, both signals being derived from a vertical-keeping reference. In Fig. 1, movement of an arm 4 of a gyro vertical 1 upon rolling of a ship positions a contact 18 relative to contacts 12 and 13 of a follow-up switch so that a two-phase motor 17 is operated to move a follow-up member 11, carrying contacts 12 and 13, towards the off position. Slow operation of member 11 ensures that it takes up a position corresponding to list of the ship and an A.C. signal dependent on list is developed by winding 23 of an inductive device 20 driven by member 11. This signal is applied to a second rotor winding of a transmitter selsyn 7, the rotor of which is displaced by arm 4 so that the A.C. output signal from windings 19 of inductive device 7 is representative of roll angle about the list position. This signal is applied to a differential receiver selsyn 39 to which signals representative of derivatives of roll are also applied from a transmitter 36. Arm 37 of selsyn 39 controls stabilizers so that roll is damped out but list remains. In a modification (not shown), instead of employing a follow-up switch, motor 17 is controlled by the output signal from selsyn 7.