Prerequisites
Read the earlier lessons in this course. The Yachtmaster Offshore security lesson introduces ISPS, and the safety lessons introduce SOLAS Chapter V, which already applies to every yacht at sea.
Learning Objectives
- Explain how international maritime law is made and enforced: the IMO and ILO, flag states, recognised organisations and port state control.
- Explain in plain terms what SOLAS, MARPOL, the ISM Code, the ISPS Code, STCW, the MLC, the COLREGs and Load Lines each cover.
- Know which certificates and records a ship carries to prove compliance.
- See how these conventions shape the daily work of a junior officer.
How Shipping Law Works
The International Maritime Organization (IMO), a United Nations agency in London, writes the main technical conventions. The International Labour Organization (ILO) in Geneva wrote the Maritime Labour Convention. A convention binds only the states that ratify it, and each country puts it into national law. In the UK that is done through Merchant Shipping regulations, explained in MCA notices: MSNs (Merchant Shipping Notices, which carry mandatory detail), MGNs (Marine Guidance Notes) and MINs (Marine Information Notes, often time-limited).
Enforcement has two layers:
- The flag state (the country the ship is registered in) surveys and certifies its ships, often delegating surveys to recognised organisations such as classification societies, and investigates casualties (MLC Reg 5.1).
- Port state control (PSC) lets any country inspect foreign ships in its ports. If conditions are clearly hazardous to safety, health or security, or there are serious or repeated breaches, the inspector can detain the ship until they are put right (MLC Standard A5.2.1). Regional agreements such as the Paris MoU share inspection results and target ships with poor records.
A ship that sails under a flag with weak enforcement still faces PSC everywhere it trades, which is why the system works.
SOLAS: Safety of Life at Sea
The first SOLAS convention was adopted in 1914 after the Titanic sank; the current version is SOLAS 1974, kept up to date by amendment. It is the most important maritime safety treaty. Its chapters cover:
| Chapter | Subject |
|---|---|
| II-1 | Construction, subdivision, stability, machinery and electrical |
| II-2 | Fire protection, detection and extinction |
| III | Life-saving appliances and arrangements |
| IV | Radiocommunications (GMDSS) |
| V | Safety of navigation |
| VI and VII | Carriage of cargoes and dangerous goods |
| IX | Management for safe operation (makes the ISM Code mandatory) |
| XI-2 | Maritime security (makes the ISPS Code mandatory) |
Chapter V applies to all vessels, including yachts: passage planning, reporting dangers, assisting those in distress and the use of signals. For larger ships it also requires equipment such as AIS, ECDIS (phased in from 2012 to 2018), BNWAS and a VDR. Ships carry a Safety Construction, Safety Equipment and Safety Radio certificate, or a single Passenger Ship Safety Certificate.
Large yachts are built to codes based on SOLAS. The Red Ensign Group Yacht Code applies to yachts of 24 m load line length and over, in commercial use, carrying no cargo and no more than 12 passengers; above that number a vessel counts as a passenger ship under SOLAS (REG Yacht Code 2024, Part A).
MARPOL: Pollution
MARPOL 73/78 has six annexes:
| Annex | Covers | Key record |
|---|---|---|
| I | Oil | Oil Record Book |
| II | Noxious liquid substances in bulk | Cargo Record Book |
| III | Harmful substances in packaged form | Dangerous goods documents |
| IV | Sewage | Sewage system certificate |
| V | Garbage | Garbage Record Book and placards |
| VI | Air pollution: sulphur limits, NOx, emission control areas | Bunker delivery notes |
Officers must know what may be discharged where. For example, under Annex V almost all garbage, including all plastics, may not be discharged anywhere at sea; food waste may be discharged only at set distances from land. Outside emission control areas, fuel sulphur is limited to 0.50%, and inside them to 0.10%. False entries in an Oil Record Book (the "magic pipe" cases) have led to multi-million dollar fines and prison sentences for officers.
ISM Code: Safety Management
The International Safety Management Code became mandatory through SOLAS Chapter IX from 1998. It requires each company to run a safety management system (SMS):
- A safety and environmental protection policy and written procedures for key shipboard operations.
- Clear lines of authority, stating the master's overriding authority and responsibility to make decisions for safety and pollution prevention.
- A designated person ashore (DPA) with direct access to the highest level of management, who monitors the safety of each ship.
- Emergency preparedness, with drills.
- Reporting and analysis of accidents, hazardous occurrences and non-conformities.
- Planned maintenance, internal audits and management review.
The company holds a Document of Compliance and each ship a Safety Management Certificate, both verified by audit. In the UK the Code of Safe Working Practices (COSWP), whose 2026 edition rewrote its ISM sections, sits alongside the SMS as the reference for safe working (MIN 688 Amendment 5).
The MGN 315 principle that the master must not be constrained by the owner, charterer or anyone else from decisions needed for safe navigation (MGN 315, para 1.3) is the same idea seen from the bridge.
ISPS Code: Security
The International Ship and Port Facility Security Code, introduced through SOLAS Chapter XI-2 after the attacks of 11 September 2001 and in force from 2004, requires:
- A ship security plan approved by the flag state, and an International Ship Security Certificate.
- A ship security officer (SSO) on board and a company security officer ashore.
- Security levels 1 (normal), 2 (heightened) and 3 (exceptional), set by the state.
- Access control, restricted areas and monitoring of cargo and stores.
- Records of the last ten port calls and security drills, and a ship security alert system.
STCW: Training and Watchkeeping
The STCW Convention sets minimum standards for certificates of competency and for watchkeeping. The MCA's MSN 1856 applies it to UK deck officers (OOW under II/1, Chief Mate under II/2, Master under II/2), and MGN 315 applies its watchkeeping principles to the bridge. STCW also contains rest hour rules that match the MLC: 10 hours in 24 and 77 in 7 days.
MLC 2006: Seafarers' Rights
The Maritime Labour Convention, in force since 2013, is often called the seafarers' bill of rights. Its five titles cover minimum requirements (age, medical certificate, training, recruitment), conditions of employment (agreements, pay, hours of rest, leave, repatriation), accommodation and food, health protection and welfare, and compliance and enforcement.
Ships of 500 GT and over on international voyages carry a Maritime Labour Certificate and a Declaration of Maritime Labour Compliance (MLC Reg 5.1.3). Every ship must have an on-board complaint procedure (Reg 5.1.5), and seafarers can also complain to port state inspectors ashore (Reg 5.2.2). Shipowners must hold financial security to cover repatriation if a crew is abandoned (Standard A2.5.2).
Others to Know
- COLREGs: the collision regulations, the same rules you learned for yachts.
- Load Lines: how deep a ship may load in each zone and season, marked by the Plimsoll mark.
- SAR Convention: search and rescue regions and coordination.
- Ballast Water Management Convention: stopping the spread of invasive species.
Worked Example: A Port State Control Inspection
A bulk carrier arrives in a European port and is boarded by PSC. The inspector:
- Checks the certificates: safety, ISM (Safety Management Certificate), ISPS (International Ship Security Certificate), MLC (Maritime Labour Certificate and declaration), load line and MARPOL certificates, and crew certificates of competency.
- Inspects records: Oil Record Book, Garbage Record Book, hours of rest records, drill records.
- Walks the ship: lifeboats, fire doors, emergency generator, accommodation and galley.
Rest records show the Chief Officer working through every port call with less than 77 hours of rest in seven days, and a fire door is wedged open. The inspector records deficiencies. Because the fire door affects safety directly and the rest records suggest a manning problem, the ship could be detained until the door is fixed and the company shows how it will comply with hours of rest, for example by adding a third mate. The deficiencies also feed the ship's risk profile, so it will be inspected more often.
Common Mistakes
- Thinking conventions apply automatically. They apply through the flag state's law and are enforced by flag and port states.
- Confusing ISM and ISPS. ISM is safety management; ISPS is security.
- Treating records as paperwork. Oil, garbage and rest records are legal documents; falsifying them is a crime.
- Forgetting SOLAS Chapter V applies to yachts. Passage planning and assisting those in distress apply to every vessel.
Summary
- The IMO and ILO write the conventions; flag states implement and certify; port state control inspects and can detain.
- SOLAS for safety, MARPOL for pollution, ISM for safety management, ISPS for security, STCW for training and watchkeeping, the MLC for seafarers' rights.
- The ISM Code requires an SMS, a designated person ashore and the master's overriding authority.
- Ships prove compliance through certificates and records, which PSC checks.
Check Your Understanding
- Which convention covers garbage disposal at sea?
Answer: MARPOL, Annex V. Discharge of plastics is prohibited everywhere at sea.
- What is the designated person ashore?
Answer: Under the ISM Code, the person in the company with direct access to the highest level of management who monitors the safety and pollution prevention aspects of each ship.
- What can port state control do with a substandard ship?
Answer: Detain it until the deficiencies are put right, when conditions are clearly hazardous or breaches are serious or repeated.
- Which SOLAS chapters make the ISM and ISPS Codes mandatory?
Answer: Chapter IX (ISM) and Chapter XI-2 (ISPS).
- Which SOLAS chapter applies to yachts as well as ships, and what does it cover?
Answer: Chapter V, safety of navigation, including passage planning and assisting those in distress.
- What certificate shows a ship complies with the MLC?
Answer: The Maritime Labour Certificate, with a Declaration of Maritime Labour Compliance, carried by ships of 500 GT and over on international voyages (MLC Reg 5.1.3).
- What are the three ISPS security levels?
Answer: Level 1 normal, level 2 heightened, level 3 exceptional.
- Why does a weak flag state not protect a substandard ship from enforcement?
Answer: Port state control can inspect and detain foreign ships in any port they visit, whatever their flag.
Sources
- International Labour Organization, Maritime Labour Convention 2006, as amended (Regulations 2.5 and 5.1 to 5.2).
- MCA, MGN 315 (M): Keeping a Safe Navigational Watch on Merchant Vessels.
- MCA, MSN 1856 (M) Amendment 1: UK Requirements for Master and Deck Officers.
- MCA, MIN 688 (M) Amendment 5: Code of Safe Working Practices for Merchant Seafarers, 2026 Edition.
- Red Ensign Group, Yacht Code 2024, Part A.