Design and operation of anchor handling tug supply vessels (AHTS)

Abstract

The deep water oilfield market is becoming more important as the conventional oilfield market in shallow water cannot meet the energy requirements from the consuming market. The Offshore Support Vessels (hereafter it is called OSVs) market is becoming booming and the demand for OSVs has never reached the extent like today in previous periods.

Anchor handling tug supply vessel, hereafter it is called AHTS, is one of the main type of OSVs and can carry out several major operations like towing, anchor handling, supply, standby and so on offshore. This thesis will describe the market demand for AHTS, the influence of AHTS design and fabrication on operation, the introduction of the anchor system of offshore installations and anchor handling operations conducted by AHTS in deepwater. The anchor handling procedures will be discussed in details which is limited to experience requirements in some sense.

Risk analysis is directly important to the success of AHTS’ operations offshore and a risk analysis is carried out for company owned vessels and rented vessels and it will refer to the technology, the procedures and the management involvement during the operation of AHTS. Several methods of risk analysis will also be mentioned in the thesis. After that, a case study about Bourbon Dolphin is discussed and the causes of the accident are illustrated combined with risk analysis. Anchor handling operations and other operations of AHTS are influenced by many criteria and any negligence may cause the failure of AHTS’ operation or delay normal operation procedures.

The main objective of this thesis is to improve people’s understanding of AHTS, and initiate people’s interest in exploring the future development of AHTS. When considering the development of OSV or AHTS, emphasis should be put on the cultivation of HSE culture which is widely employed in the global offshore market.