What are MIN, MGN, MSN

Legal Structure


Marine information notes (MINs) tend to give information that’s valid for a short period of time, such as timetables for MCA exams relevant to a small group of people, such as training establishments or equipment manufacturers.

EXAMPLE MIN 442 Training for ECDIS as primary means of navigation

MIN have a limited life, the expiry date is shown in the notice.


Marine Guidance Notes give advice on how to comply with MSN or other safety advice.

EXAMPLE MGN 315 Keeping a safe navigational watch on merchant vessels

MGN remain in force until replaced.

The letter suffix after the M-notice number tells you if it relates to merchant ships and/or fishing vessels:

  • (M) for merchant ship
  • (F) for fishing vessels
  • (M+F) for both merchant ships and fishing vessels


MSNs contain the technical detail of regulations called ‘statutory instruments’ (SIs). This is mandatory information, and must be complied with under UK legislation.

EXAMPLE MSN 1858 Training & Certification Guidance: UK Requirements for Deck Officers on Large Yachts (over 24m)

MSN remain in force until repealed.

Most of the UK’s law is made not via Acts passed through Parliament  but instead via delegated legislation. The most common form of delegated legislation is a Statutory Instrument.

The content of Statutory Instruments is normally prepared by Government Departments and this means that the Government can fill out the details of primary legislation or sometimes even change primary legalisation without having to pass another Act through Parliament. Delegated legislation is necessary to regulate modern British society, it would be impossible for Parliament to pass all the laws written via delegated legislation in ordinary Parliamentary sessions. Each year delegated legislation exceeds primary legislation by between two and five times.

Statutory Instruments are almost never debated on the floor of the House of Commons and less than 0.001 Statutory Instruments have ever been voted down by Parliament

Statutory Instruments can be laid by either the negative or affirmative resolution procedure. If a Statutory Instrument is laid as a negative instrument then it is presented to Parliament and if no member votes to annul it in the following 40 days then it becomes law. If a Statutory Instrument is laid as an affirmative instrument then a Committee  in each of the House of Lords and Commons must debate and approve it before it becomes law. Committees however, are  generally only made up of 15 members of Parliament in comparison to primary legislation which is debated on the floor of the House of Commons.

Lots more on UK Law can be found here but do not spend time on this if studying for a CoC