Shipowners. Basic Stability for Small Vessels

Description

The Shipowners' Protection Limited, London, 2007. 53 p.Many different types of vessels are entered in the Ciub each possessing their own unique stability requirements.Generally speaking tankers, bulk carriers and passenger vessels retain more than sufficient stability to ensure compliance with the regulations when fully loaded. Dry cargo ships, container carriers and barges are subject to large reductions in stability when loaded therefore care must be taken to ensure the condition of the vessel complies with the regulations which lay down the minimum stability requirements. If these are not complied with, then the safety of the vessel, her crew and cargo will be compromised.Over the years the Club has dealt with a number of claims involving general cargo vessels and container ships that have been caused by the vessel having inadequate stability and being allowed to undertake a voyage in that condition. There have also been a large number of similar incidents involving flat top barges loaded with break bulk, containers, scrap metal or combinations of all three. In most cases the lack of sufficient stability has not been made apparent until an external force has acted on the vessel caused by heavy sea conditions, a sharp alteration of course or the pushing of an assisting tug.Prompted by these claims, the Club has published this booklet on basic stability aimed primarily at Members and crews of dry cargo vessels. The purpose of the booklet is to explain the fundamentals of stability and explanations as to how it can be determined which is not always readily understood by crews and personnel responsible for loading vessels. All to often the GM is taken to be the measure of a vessel's stability and this is an incorrect assumption.Introduction Lack of Understanding of Stability Criteria Stability Requirements Failure to Observe Basic Principles Pre Load Requirements Free Surface Effect Estimating Centre of Gravity Container Heights Container Weights Draft Cranes and Derricks Overloading Reductions in Freeboard Failure to Confirm the Vessel's Condition Errors In Calculations Computers Conclusion Appendices Proforma Calculation Sheet {VCG) Examples of Calculating Stability Conditions Case Studies