UK MCA circulars — MSN, MGN, MIN
The UK Maritime and Coastguard Agency (MCA) publishes three overlapping series of maritime circulars: MSN (Merchant Shipping Notices), MGN (Marine Guidance Notes), and MIN (Marine Information Notes). Together they constitute the practical implementation of UK Merchant Shipping Act statutes + SOLAS/MARPOL/STCW obligations for UK-flagged vessels + UK port-state control. Foreign-flag vessels calling UK ports rely on MSN/MGN content for PSC compliance expectations. Every UK-flag Master and DPA maintains a current subset of these notices relevant to the vessel type.
The three series distinguished
MSN (Merchant Shipping Notice)
Have mandatory legal effect where cited by UK statutory instrument. Numbered MSN 1801+ (continuing from historical series). Examples: MSN 1789 crew accommodation on UK-flag vessels, MSN 1858 STCW correlation table, MSN 1848 pilot transfer arrangements. When UK Merchant Shipping (Various) Regulations reference an MSN, the referenced content is binding.
MGN (Marine Guidance Note)
Best-practice guidance without direct legal force but frequently referenced in prosecutions + used as evidence of standard-of-care in liability cases. Numbered MGN 1+. Examples: MGN 315 fatigue, MGN 320 shipboard exercises, MGN 528 anti-piracy, MGN 654 cyber security best practice.
MIN (Marine Information Note)
Temporary or limited-duration information, typically superseded within 12-24 months. Announcements of new regulations, industry consultations, temporary operational restrictions.
Selected operationally-important notices
| Notice | Subject | Cross-link |
|---|---|---|
| MSN 1848 | Pilot transfer arrangements — SOLAS V/23 UK implementation | Pilotage |
| MSN 1858 | STCW model course correlation table — UK CoC equivalences | Model courses |
| MSN 1789 | Crew accommodation on UK-registered vessels | MLC 2006 |
| MSN 1809 | Hours of rest + record-keeping | Hours of rest |
| MGN 315 (M) | Fatigue guidance for shipowners and officers | Fatigue management |
| MGN 320 (M) | Shipboard drills + exercises minimum requirements | SOLAS III |
| MGN 371 (M) | Entering enclosed spaces — safety guidance | Enclosed space |
| MGN 528 (M) | Anti-piracy: transiting high risk areas | Piracy |
| MGN 636 (M) | Passage planning guidance — including UKC calculation | Passage planning |
| MGN 654 (M) | Cyber security onboard ships — best practice | Cyber security |
| MGN 669 (M) | Ballast water management — UK application | BWM |
| MGN 682 (M) | MARPOL 0.10% ECA sulphur — UK enforcement | ECA checker |
| MGN 691 (M) | CII rating + SEEMP Part III UK implementation | CII |
| MGN 706 (M) | IMO 2020 sulphur cap — carriage prohibition + non-compliant fuel handling | MARPOL VI |
| MGN 731 (M+F) | Piracy + armed robbery — updated BMP5 references | Bab-el-Mandeb |
Finding + citing an MCA notice
- Full catalog at gov.uk/collections/msn-mgn-and-min — collections by year + subject.
- Individual document pages carry PDFs (typically 5-20 pages).
- Citation format: "MGN 528 (M) (2018) — Anti-piracy" where (M) = merchant vessels, (F) = fishing vessels, (M+F) = both.
- Superseded notices remain findable but are flagged; check the "This notice supersedes..." block.
- UK-flag vessels: Master should maintain the current subset relevant to vessel type + trade in the SMS document reference library.
See also
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