The International Maritime Organization (IMO) has agreed to use the International Marine Contractors Association (IMCA) proposals as the basis for the review of the IMO Guidelines for vessels with dynamic positioning (DP) systems (MSC/Circ.645). The review will be taken forward by an IMO intersessional correspondence group that will further develop the draft, with a view to finalising it at the next meeting of the IMO Ship Systems and Equipment (SSE) sub-committee, in 2016.
“IMO’s circular 645 is the established international standard for DP systems. The guidelines have successfully provided the framework on which national regulations and classification society rules are based, and which are supplemented by a growing body of more detailed industry guidance,” explains IMCA’s Technical Director, Jane Bugler.
“Over the decades since MSC/circ.645 was first published in 1994, DP has evolved from being a tool primarily for mobile offshore drilling units (MODUs) maintaining position over offshore wells, to being employed for a wide range of position keeping operations, with systems being fitted on much larger numbers of new vessels and on an increasingly diverse set of vessels, from offshore units to shuttle tankers and passenger vessels.
“645 has been working well but needs amending slightly to reflect changes in both technology and industry practice, including performing Failure Modes and Effects Analysis (FMEAs) on the DP system by identifying and analysing the consequences of any single point failure to ensure that, if a failure were to occur, it would not exceed the worst case failure design intent (WCFDI) or cause the vessel a significant loss of position by ‘drift off’ or ‘drive off’. The IMO review will also consider the inclusion of DP equipment class 0, to reflect the four equipment classes that are now recognised, and the flag state certification provisions.
“The IMCA proposals were developed by an internal workgroup, with input from co-sponsors that include a number of governments and other industry organisations. We look forward to a highly constructive time working on MSC/circ. 645 with the correspondence group.”
IMCA’s DP role
IMCA publishes a variety of guidance documents on DP, setting out industry good practice based on the cumulative experience of its members to help ensure safe and efficient DP operations. ‘Guidelines for the design and operation of dynamically positioned vessels’ is the association’s key document. It is regularly reviewed and updated with a new version due for publication during 2015. The document contains generic guidelines for the design and operation of DP vessels, and the guidance has now been increased to include 17 differing vessel types.
Other documents address annual DP trials programmes (IMCA M 190 and IMCA M 191) for DP vessels, based on comprehensive and standard report formats for ease of use by vessel operators and their clients. IMCA also produces technical reports, aimed at helping vessel operators review, specify, maintain and use a variety of positioning systems, thrusters, power and vessel management systems and other equipment.
The IMCA database of incidents on DP vessels extends back over more than 30 years and all DP vessel operating companies are encouraged to participate in reporting incidents for mutual benefit. Each year reports received are collated and an anonymised analysis of the incidents is published. IMCA also publishes and circulates DP safety flashes.