The Influence Of Ballast Water On Bulk Carriers' Safety Operations

In the international shipping industry, the bulk carriers' transportation accounts for above goods traffic's 30%, the bulk carrier has become transports ships' main army. For the past several years, the bulk carriers' accident repeatedly occurs, in many factors that influence bulk carriers' security, the hull strength is at the main position. The ships' cargo operation and the ballast exchange operation are important factors that affect the hull strength. During the ship is in cargo operation or navigate in ballast condition, the ballast water can trim the ship and improves the ships stability, the more important is ballast water's reasonable operation can improve hull's longitudinal strength, reduces the hull structure to be weary. The core of controling strength when the bulk carrier is in cargo operation or changing ballast, is to make optimize ballast plan or ballast exchange plan, is to minize the influence that caused by shearing force and bending moment during the entire handling process. Reduces risk in transportation, serves for bulk carriers' safety transportation.This article unifies the author four years' navigation practice, has conducted the research to the bulk carriers' ballast plan as well as the ballast exchange plan. In the key research bulk carriers' ballast plan as well as the ballast water exchange plan's strength control question, and proposed the formulation ballast plan and the optimized ballast exchange plan essential method.(1)In the ballast plan's formulation process, must first determine the cargo operation sequence, the cargo quantity that each round should be handled, simultaneously must understand the cargo handling speed, the ballast pump's working efficiency. Then the definite ballast plan, this article uses the theory that few loads influence hull strength to determine the ballast quantity in the ballast plan formulation process, the ballast position, the ballast opportunity. And this article detailed state maters which should be paied attention during ballast. (2)In the ballast exchange plan formulation's process, this article uses load critical point determine ballast tanks' matching, to control the change of the bending moment during the ballast water is exchanging. Carries on the evaluation to all ballast tanks' matching by the superior evaluation method, the plan in which shearing force changes stablest and equal is the superior ballast exchange plan. To some special ballast tanks on a ship cannot carries on the ballast exchange by empty&refilling method, proposed overflow method. And this article elaborates the way to calculate the prepared presses, introduced the matters that should be paied attention to during changing ballast water by overflow method.