Fishing vessels are chosen as a major test case while other types of ships are also used. Fishinvessels are generally smaller with a unique operating nature and the accidents concerning thesvessels have been overlooked in the past. Most fishing vessels are owner operated and lack thorganisational structure of merchant vessel owners and operators. This leads to the difficulty igathering accident/failure information for a safety analysis.
Since the fishing industry is starveof safety and reliability data, conventional safety and risk assessment techniques may notbreadily applied. The available quantitative techniques require a certain amount of failure data iorder to make a reasonable safety prediction. The novel methods described in this book wiaddress this setback of the traditional methods by integrating within their models the ability thandle vague and uncertain data in an effective manner to produce a reasonably accurate safetassessment.
These novel methods will integrate hazard identification, risk quantification anranking with formal decision making techniques so that safety improvements made to new awell as existing vessels are effective and justified.
The body of this book is divided into eleven Chapters. Each Chapter is summarised herehighlighting the salient points delivered. Chapter 2 highlights the international conventions that govern fishing vessel safety and somof the safety programmes that have been implemented by the International MaritimOrganization (IMO) member states. The data that were collected andanalysed from variousources including the Department of the Environment, Transport and the Regions (DETR) anthe Marine Accident and Investigation Branch (MAIB), are presented.
The findings of thaccident data analysis are described. A statistical analysis of containership accidents is alsbriefly conducted.
Chapter 3 gives an introduction to typical safety analysis techniques. The advantages andisadvantages of each method are reviewed. This is followed by a proposed approach tidentifying hazards on board ships. Chapter 4 describes both the offshore safety case approach and formal safety assessment oships. The current practices and the latest development in safety assessment in both the marine and offshore industries are described. The relationship between the offshore safety case approach and formal ship safety assessment is described and discussed. The study of risk criteria in marine and offshore safety assessment is carried out. The recommendations on urther work required are finally given.
Chapter 5 discusses the inception of Formal Safety Assessment (FSA), originally proposed by the UK Maritime & Coastguard Agency, in the maritime applications. The FSA is applied to fishing vessels with an illustrative example. The application of the FSA framework to containerships is also described. Detailed discussions on several aspects ofFSA’sapplicationto ship design and operation are given.
Chapter 6 describes a new approach for modelling the occurrence probability of a hazard and its severity using Fuzzy Set Theory (FST) with Fault Tree Analysis (FTA). The literature survey indicates that the common problem in quantifying these parameters (of a failureevent) is oftn the small sample size and the statistical uncertainties which are correspondingly high. The approach described utilises FST and expert judgements to deal with this high level of uncertainty. It involves the generation of a fault tree of known events and its synthesis with fuzzy arithmetic to produce a fuzzy probability for the top event (an undesirable event).
Linguistic terms such as Very High, High, Moderate, Low and Remote are used to obtain such an estimate. Mathematical formulas used for calculations in the fault tree are derived from the theory of probability and integrated with fuzzy arithmetic on t~-cut sets. The risks associatedwith failure events are determined by combining the occurrence likelihood and possible consequences to produce a risk ranking. A trial application of the approach is carried out.