Static analysis of axially moving cables applied for mining nodules on the deep sea floor

The two-dimensional static mechanics of axially moving cables used in two-ship continuous line bucket (CLB) system for mining manganese nodules from the seabed are theoretically examined. Two coordinate systems (local and global ones) are used for obtaining local and global solutions, and for physically matching the two solutions. The analytical result shows that the effect of centrifugal force caused by the axial motion on the flexural loads near the touchdown point is very small. The static equilibrium of the system considering the dynamic friction between the sea floor and axially moving cable is investigated to demonstrate that the rate of collection of the nodules by bucket and the interval of the buckets remarkably influence the design of the system for keeping it mechanically stable.

► The static mechanics of continuous line bucket system is examined.
► A theory composed of local and global solutions and matching condition is developed.
► Mechanical link between ascending and descending cables is examined.
► A critical value of the rate of nodule collection is important for the system design.