IMCA issues guidance on DP positioned jack-ups and use of dumb bargesPublications // May 17, 2013
An increasing number of members of the International Marine Contractors Association (IMCA) are involved with the offshore renewables sector and for this reason the association has published ‘Guidance for the Positioning of Dynamically Positioned (DP) Jack-up Vessels on and off the Seabed” (IMCA M223) and an updated version of their information note 'Inspection and Auditing of Manned and Unmanned Barges’. Both are aimed at ensuring and enhancing offshore safety.
“The aim of IMCA M223 is to provide the owners and operators of dynamically positioned (DP) jack-up vessels with guidance to create procedures for going onto and leaving location,” explains IMCA’s Technical Director, Jane Bugler.
“A DP system interfaces with the vessel’s propulsion systems to hold the vessel in position against external forces (such as wind and waves) that are acting to move the vessel.
“For DP vessels with jack-up capability – when a vessel moves into position on DP but intends to undertake the work on location as a jack-up vessel – there can potentially be excessive stresses induced into the legs during the transitional period from being on DP to ‘leg touchdown’ to soft pinning of the legs. The first leg contact with the seabed will restrict the vessel’s motion which may indicate a position error to the DP system. This could the lead to an increase of thrust of the vessel’s positioning propulsion systems and consequently may impart these excessive stresses on the legs.”
IMCA M223 has sections on Risk Analysis (vessel characteristics; environmental conditions and loading; site specific assessment integrity; and DP specification and performance); Background Material (that encompasses company procedures; vessel procedures; and information for each location); and covers Procedures for a DP Jack-up Vessel Going on and Leaving Location.
Like all IMCA guidance it is free to download from the IMCA website for members and non-member alike. Printed copies can be purchased at £5.00 for members and £10.00 for non-members via the IMCA website at www.imca-int.com and from email@example.com.
Update of dumb barge information note
IMCA published ‘The Inspection and Auditing of Manned and Unmanned Barges’ as an information note in Autumn 2012. A so-called ‘dumb barge’ is a vessel that is unmanned during transits, does not have its own propulsion and must be either towed or pushed to its destination.
This has now been updated to include a new short section on ballast arrangements and further information on anchoring. This information is also available for download from the IMCA website
For further information on IMCA and its work on behalf of its 900+ member companies in over 60 countries is available from www.imca-int.com and from IMCA, 52 Grosvenor Gardens, London SW1W 0AU, UK. Tel: +44 (0)20 7824 5520; Fax: +44 (0)20 7824 5521; and firstname.lastname@example.org.