Improvements in linked-spar motion-compensated lifting system
Abstract
An improved system for operating a lifting cable over the side of a ship at sea in which a spar buoy having an adjustable lifting capacity is coupled to the shop by a rigid linkage which is free to pivot on an axis attached to the ship deck, and operates to decouple the motion of the ship from lifting cable. The spar buoy is attached to a gimbal sheave assembly having a disengageable connector and tension line for drawing the connector into engagement with a mating socket at the outward end of a linkage boom. A narrow upper section of the spar buoy is provided with a plurality of vertical tubes and valves which by flooding or evacuation operate to vary the effective water plane area of the buoy for continual fine tuning and optimally adjusting of its natural heave mode characteristic frequency.
- Publication:
-
Patent Application Department of the Navy
- Pub Date:
- October 1984
- Bibcode:
- 1984padn.rept.....O
- Keywords:
-
- Buoys;
- Dynamic Loads;
- Jacks (Lifts);
- Materials Handling;
- Motion Stability;
- Onboard Equipment;
- Ships;
- Winches;
- Gimbals;
- Linkages;
- Oceans;
- Patent Applications;
- Sea States;
- Engineering (General)