Safety performance on the UK Continental Shelf is normally considered to be of a high standard, although there are still many incidents and accidents. This paper discusses some of the findings in an offshore support vessel safety research project being carried out at both Staffordshire and Liverpool John Moores Universities. In this paper following a brief review study of the uses of various types of existing offshore support vessel, a comprehensive statistical failure data analysis of the vessels is carried out based on a Ship/Platform Collision Incident Database drawn from the Health and Safety Executive (HSE). The variation of incident frequency with time for different types of offshore oil and gas installations, and for different vessel types has been established. A total number of 394 records, within the period 1980 to 1997, are investigated in this study. The analysis identifies that:- 1. 3.55% incidents were classed as 'severe'. 10.9% incidents as 'moderate' and the remainder as 'minor', 'none' or 'unspecified'; 2. the vast majority of incidents (97.97%) have occurred with oil field offshore support vessels or attendant vessels; 3. supply vessels form the most frequent colliding vessel type, accounting for 249 out of 394 incidents [63.2%]; 4. more incidents have occurred during the period September to February [52.5% of the total known cases]; 5. the total risk associated with supply vessels collision appears to have decreased with time, notably for fixed installations; 6. the two most common operating circumstances at time of collision for supply vessels were platform approach and container or bulb transfer; as for standby vessels the major operating circumstance was platform approach and close support; 7. human control failure in terms of misjudgement is the most frequent quoted primary cause for failure, especially for 'severe' or 'moderate' incidents/accidents. Mechanical control failure is the second most frequent quoted primary cause; 8. the most probable collision orientation for supply vessels is stem-on for both fixed and mobile installations, accounting for about 50% of all known cases; 9. the number of incident occurrence in the Southern North Sea is about 30% of the total; 10. for incidents resulting in 'minor', 'none' damage the risk in the Northern North Sea is about 3 to 4 times higher than that for the Central North Sea and 10 times higher than that for the Southern North Sea. The statistical analysis reveals that good seamanship by vessel masters is probably responsible for mitigating the magnitude of many of the impacts that do occur and also that there is a need for improvement in safety performance.
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