Why Two Layers of Control Exist
A ship at sea owes its legal existence to its flag state. The flag state grants the right to fly its ensign, issues certificates, and is responsible under UNCLOS for ensuring its ships comply with international conventions. The master is the flag state's representative on board in practical terms — every certificate, every log entry, every drill record is an exercise of that relationship.
The problem is that a flag state cannot physically inspect its ships in every port worldwide. Port state control (PSC) exists to fill that gap. Under UNCLOS Article 94 and the MOU framework, a coastal state may inspect any foreign-flag vessel in its port to verify that the ship and its crew meet the standards of the international conventions the port state has also ratified — SOLAS, MARPOL, MLC 2006, STCW and others. The port state is not enforcing its own law; it is verifying compliance with conventions that both states have accepted.
Flag State: The MCA's Role for UK-Flagged Yachts
The MCA acts as flag state authority for Red Ensign Group vessels. For yachts, the applicable code is the Red Ensign Group Yacht Code (REG YC Part A, which superseded LY3). The MCA issues the ship's statutory certificates (if applicable), approves the SMS under ISM, and may conduct flag state inspections. The master must ensure all flag state certificates are valid, held on board in their correct form, and available for inspection at any time.
Port State Control in Practice
A PSC officer (PSCO) may board at any port of call. Their authority is to inspect certificates first; if these are in order and there is no clear ground for further inspection, the boarding should be brief. If certificates are deficient or there are clear grounds — crew complaints, visible pollution, an obvious hazard — the PSCO may conduct a more detailed inspection.
Deficiencies are categorised. Minor deficiencies are noted and must be rectified. A detention occurs when the ship is unsafe to proceed to sea. Detention is a serious commercial and reputational event and the master must notify the owner/manager and flag state immediately.
The Master's Readiness Posture
At command standard, readiness for PSC is not a reaction to a boarding — it is the default state of the vessel. Practically, the master should maintain:
- All statutory certificates valid, originals on board (SMC original; DOC copy is acceptable).
- Logs current: ORB, Garbage Record Book (if applicable), hours of rest records, Official Log Book drill records.
- Crew documents valid: STCW certificates, medical certificates, watchkeeping records.
- Safety equipment serviced and within survey dates.
- Familiarity with Paris, Tokyo, or relevant regional MOU targeting criteria — a vessel with a poor PSC history is more likely to be selected for detailed inspection.
The master who cannot produce a document on demand has already failed the first test.