Determining the grounding length of an axially moving cable in a two-ship continuous line bucket system

This study investigates the two-dimensional static mechanics of an axially moving cable used in a two-ship continuous line bucket (CLB) system for exploiting mineral resources deposited on the sea floor. The aim of this study is to formulate a theory for estimating the grounding length of the cable. The theory is governed by the relation for the static equilibrium of forces acting on the cable and geometrical conditions imposed on the submerged length of the cable and on the distance between the two ships supporting the cable. Two algorithms involving a couple of iterations are developed for obtaining the grounding length. The calculation using the algorithm shows that the grounding length varies in response to changes in the rate of collection by the bucket and the bucket interval. The calculation also demonstrates that the maximum grounding length is determined on the basis of the geometry of the submerged part and that the grounding length ranges from zero to the maximum depending on the distance between the two ships.

▸ An axially moving cable in a two-ship continuous line bucket system is considered. ▸ The grounding length of the cable is computed by the static mechanics of the cable. ▸ Two geometrical conditions of the submerged part of the cable are also considered. ▸ Properties of the buckets affect the configuration of the cable. ▸ The distance between two ships has to be regulated for the grounding length desired.