Ship maintenance was initially considered as more of a financial burden than as a way to preserve safety, environment and quality transportation. The benefits from applying a sound and systematic maintenance policy are emerging both in the minimisation of unnecessary downtime as well as in the increase of operational capability. In this paper, a novel predictive maintenance strategy is demonstrated, combining the existing ship operational and maintenance tasks with the advances stemming from new applied techniques. The initial step for the application of the above-mentioned strategy is also shown regarding the machinery space of a cruise ship. Well-known tools are applied such as Failure Modes, Effects and Criticality Analysis (FMECA) and Fault Tree Analysis (FTA). Outcomes of this study are the identification of the critical components of the system, the estimation of the reliability of the overall system and sub-systems, the prioritisation of the maintenance tasks and finally the availability of the specific end events/items

The application of pod propulsion in a number of vessel types has been increasing steadily over the last two decades. This increase is attributed to the great advantages being offered by pod propulsion systems such as high manoeuvring capability, low noise and vibration, low fuel consumption, etc. Despite these advantages, operators are cautious due to the encountered teething problems, especially in the very competitive passenger ship market, where reliability and the maintainability of the service are crucial. This paper presents a reliability assessment methodology and its application to a combined four‐pod propulsion system on a vessel equipped with two fixed‐ and two rotating‐pod units. The assessment methodology made use of Failure Mode and Effect Analysis, Fault Tree Analysis (FTA) and Markov Analysis complementarily. In the FTA, minimal cut set, reliability importance measure and availability analyses were also considered. From the quantitative reliability assessment, the calculated reliabilities of each fixed‐ and rotating‐pod unit, their components' reliabilities as well as the reliability of the combined four‐pod propulsion system showed good agreement with the acceptable reliability criteria suggested by the pod manufacturers/operators based on the service experience. Copyright © 2006 John Wiley & Sons, Ltd.

Double hull (DH) tankers may be more effective than single hull (SH) tankers in pollution prevention because they have a second barrier, the inner skin, to oil outflow in the event of side damage. The actual effect of DHs calls for quantitative study. This paper presents a comparative study on the side structure resistance to collisions. A DH Aframax tanker and an SH Aframax tanker of similar size were selected for the study. The two vessels were assumed to be struck by a same bulbous bow in different locations and angles. The bow was assumed to be rigid and different non-linear materials and contact models were considered for the struck tankers based on the original designs. The DH tanker was found to be superior to the SH tanker in relation to resistance to side structural damage. Finally, by using the simulation results, the distribution of damage extents for DH tankers is proposed based on the historical damage extents, which are mainly for SH tankers

The paper presents detailed results of a comprehensive analysis pertaining to Aframax tanker incidents and accidents that occurred in the last 26 years. The thorough review of the captured accident database information and the analysis of the historical records provided essential qualitative and quantitative information on a variety of parameters relevant to risk-based methodologies, namely the degree of severity and frequencies of accidents broken down into the pre-1990 and post-1990 periods, the spilled tonne rates and the impact of hull design and of ship's age, particularly on non-accidental structural failure accidents and geography of worldwide oil spills. The generated information enables conclusions on Aframax tanker accidents and of tankers in general to be drawn, for further exploitation in risk based design, operation and regulations

No abstract