Three key dynamic positioning (DP) documents have been launched by the International Marine Contractors Association (IMCA). The first ‘Recommended Practice for the Operation of Class 1 DP Vessels’ (IMCA M268) is the marine contracting industry’s first comprehensive guideline for the safe and efficient operation of the ever-increasing number of DP1 vessels in operation – largely in the rapidly emerging global offshore wind industry
The second is a rewrite of ‘Recommended Practice for Specification and Use of DP Capability Plots’ (IMCA M140) reflecting the current way in which DP vessels are operated and used. This guidance is used primarily by project planners enabling them to select the right DP vessel for a specific task with increased confidence. The third is a revision of ‘Recommended Practice on Operational Activity Planning’ (IMCA M220)
“As with all our DP documentation these three newly launched documents are produced by our DP Committee, comprised of vessel owners and operators, suppliers and regulatory bodies, to ensure safe operations aboard the 4,241* DP vessels working offshore,” explained IMCA Technical Adviser – Marine, Richard Purser.
“The 1,080* vessels with DP1 systems now account for some 25% of the offshore DP-equpped fleet and the figure is growing fast. IMCA M268 sets out best practice in the operation of DP1 ships, which do not have the redundant capabilities of DP class 2 and 3 systems.
“It emphasise the importance of understanding the limitations of DP1 vessels and contains recommended guidance on achieving operational preparedness and ensuring that crew members have the required training and experience. Power system redundancy is a critical mechanism within DP systems that ensures a vessel can maintain its position in the event of the failure of power components.”
Given the limitations, IMCA now recommends that:
- DP1 vessels should not undertake any operation where a loss of position or heading would be deemed unacceptable
- Using only two differential GNSS systems for position reference is not acceptable for DP1 operations
- The lower level of redundancy on DP1 vessels requires a significantly higher level of experience and understanding. There is no guarantee that a DP operator (DPO) from a DP2 vessel has the transferable skills to operate a DP 1 vessel safely and efficiently.
All three publications can be downloaded by members from the IMCA website.
*From Clarkson’s data
