Commercial Vessel Compliance

D8 OCS MSIB: Reporting requirements and mooring arrangements for MODUs and velssels completing OCS activities intending to cold stack

The Eighth District Outer Continental Shelf Officer in Charge has issued Marine Safety Information Bulletin 22-01 titled “Reporting Requirements and Mooring Arrangements for MODUs and Vessels Completing OCS Activities Intending to Cold Stack”.

It is critical for the Coast Guard to have current and accurate vessel location information during heavy weather events. Inaccurate and incomplete information has delayed Coast Guard response efforts in the past, and could do so in the future. In anticipation of an active 2022 tropical cyclone season, the Eighth Coast Guard District is reminding owners and operators of Mobile Offshore Drilling Units (MODUs) and other vessels completing Outer Continental Shelf (OCS) activities (e.g. accommodation vessels, support vessels, pipelay vessels, and others described in 33 CFR 146.401) of the requirement to notify the Coast Guard when these units are being relocated.

  • Per 33 CFR 146.202(b), the owner or operator of a MODU must notify the District Commander before relocating the unit. This includes units that are in, or being transitioned to, a “cold stacked” or non- operational status. For any MODU currently on the OCS that has been relocated from its original position without the required notification, owners must provide the current location and 24-hour contact information as soon as possible. These notifications should be made to the Eighth District OCS Division at Please note that this is in addition to the requirement to make certain notifications to the National Vessel Movement Center in accordance with 33 CFR 146.215(a) or Subpart C of Part 160.
  • For other vessels engaged in OCS activities, owners or operators must submit updated Notices of Arrival to the National Vessel Movement Center in accordance with 33 CFR 146.405 or Subpart C of Part 160, and it is requested that they also notify and provide 24-hour contact information to the Eighth District OCS Division at when the vessel is being placed in a “cold stacked” or non- operational status.

When preparing to “cold stack” a vessel or MODU offshore, the Coast Guard strongly encourages operators to follow Classification Society guidance (such as the American Bureau of Shipping’s June 2017 “Guide for Lay-up and Reactivation of Mobile Offshore Drilling Units” or other Classification Society guidance) or other applicable standards regarding mooring arrangements. It is also highly recommended that owners and operators ensure these arrangements are reviewed by a naval architect or professional engineer and, at a minimum, the following are considered:

  • Potential heavy weather impacts, to include storm surge
  • Proximity to shipping channels, OCS facilities, and pipelines
  • Oil or hazardous materials remaining on board
  • Lighting and sound signals (see also 33 CFR 143.15 and 33 CFR Part 67)
  • Emergency response and recovery procedures

For questions or clarification on this MSIB, please contact the Deputy OCS Officer in Charge, Marine Inspection, at (504) 671-2106.

This blog is not a replacement or substitute for the formal posting of regulations and updates or existing processes for receiving formal feedback of the same. Links provided on this blog will direct the reader to official publications, such as the Federal Register, Homeport and the Code of Federal Regulations. These publications remain the official source for regulatory information published by the Coast Guard.

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