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Guidance on DP positioning jack-up vessels from IMCA

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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 The Inspection and Auditing of Manned and Unmanned Barges’. Both are aimed at ensuring and enhancing offshore safety.

Jane Bugler

Jane Bugler

“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 publications@imca-int.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

About IMCA

  • IMCA is an international association with more than 915 members over 60 countries representing offshore, marine and underwater engineering companies. IMCA has four technical divisions, covering marine/specialist vessel operations, offshore diving, hydrographic survey and remote systems and ROVs, plus geographic sections for the Asia-Pacific, Central & North America, Europe & Africa, Middle East & India and South America regions. As well as a core focus on safety, the environment, competence and training, IMCA seeks to promote its members’ common interests, to resolve industry-wide issues and to provide an authoritative voice for its members.
  • IMCA publishes some 200 guidance notes and technical reports – many are available for free downloading by members and non-members alike. These have been developed over the years and are extensively distributed. They are a definition of what IMCA stands for, including widely recognised diving and ROV codes of practice, DP documentation, marine good practice guidance, the Common Marine Inspection Document (CMID) – now available electronically as eCMID, safety recommendations, outline training syllabi and the IMCA competence scheme guidance. In addition to the range of printed guidance documents, IMCA also produces safety promotional materials, circulates information notes and distributes safety flashes.

 

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