For SC, build a mental map of the certification system first: the Convention sets requirements, the Code Part A makes them mandatory, certificates of competency and proficiency carry different meanings, and flag-state endorsements connect a mariner's documents to a specific ship's registry. Practice by tracing each scenario through that chain before answering.
Why Part A and Part B of the STCW Code Are Not Interchangeable
The STCW Convention sets the framework, and the Code attached to it carries the detail. Part A contains mandatory provisions; Part B contains recommended guidance. Distinguishing the two is a core reading skill for this credential.
When you read any statement about training, certification, or watchkeeping, classify it first: is it a binding minimum standard, or is it a suggested way a Party might implement the standard? Part A states the required outcome — for example, the standards of competence a candidate must demonstrate. Part B suggests methods, examples of evidence, and implementation approaches. A statement phrased as 'shall' or 'must' points toward Part A; language like 'should' or 'is recommended' points toward Part B.
Make this classification mechanical during study. On each flashcard or practice item, write 'A' (mandatory), 'B' (guidance), or 'Convention' (the treaty text itself) before answering the question. Then, in scenario practice, use the tag to decide weight: a scenario describing a recommended practice that was skipped is a weaker finding than one describing a missed mandatory standard. This tagging habit also helps you notice when an exam-style item blends the two layers in a single sentence.
- Convention: the treaty text and annex containing the obligations of Parties.
- Code Part A: mandatory standards of competence, training, and certification.
- Code Part B: recommended guidance on implementing Part A.
- Study tag: label every fact you learn as Convention, A, or B.
COC, COP, and Flag-State Endorsement: Three Documents, Three Jobs
A certificate of competency (COC) certifies a mariner's competence at a stated level and function. A certificate of proficiency (COP) certifies completion of specific required training. A flag-state endorsement authorizes service on ships of that flag.
The COC is the central document: it records the capacity (for example, officer in charge of a navigational watch) and the level at which the holder may serve. A COP attaches to a narrower training requirement — safety-related or role-specific training such as basic safety training or training for specific ship types — and it often attaches to, or supports, the COC rather than standing alone as proof of a full onboard role.
The endorsement is the connector between documents and ships. It is issued by the flag state of the vessel the mariner will join, confirming that the flag administration recognizes the competency certified by the issuing administration. The three documents differ in issuer (issuing administration, training provider path, flag administration), in scope (full role, specific training, permission to serve on that flag), and in what triggers their issue. Comparing them side by side, rather than memorizing definitions in isolation, is what makes scenario practice tractable.
| Document | Issued by | What it shows | Typical anchor in a scenario |
|---|---|---|---|
| COC | The administration of the issuing Party | Competence in a function at a stated level | The officer's rank and watchkeeping capacity |
| COP | Under the issuing administration's arrangements | Completion of a required specific training course | Safety training or ship-type training attached to a role |
| Flag-state endorsement | The flag administration of the ship joined | Recognition of a foreign COC for service on that flag | Cross-flag employment under the recognition procedure |
| Medical fitness certificate | Approved medical practitioner under the administration's rules | Fitness for sea service | A separate gate checked alongside the COC |
Matching Certificate Level to Onboard Role: Functions and Levels
Certification is organized by function — navigational, engineering, radio, and related areas — and by level of responsibility, commonly described as support, operational, and management. Duties claimed onboard must match the level shown on the COC.
Level describes responsibility: a support-level certificate covers duties performed under supervision; operational level covers officer roles with watchkeeping responsibility; management level covers senior roles with command or overall engineering responsibility. Function describes the department or domain: deck, engine, radio communications, and the other functions the Convention addresses. A capacity such as 'officer in charge of an engineering watch' therefore reads as function plus level plus role, and every scenario should be decomposed that way.
In applied practice, check the match explicitly. If a scenario describes a mariner performing a management-level task — for example, taking overall responsibility for an engineering department — verify whether the document described supports that role, or whether it is an operational-level certificate plus a COP. Training a habit of rewriting each scenario's first sentence as 'function: ___, level: ___, role: ___' forces the decomposition and exposes mismatches between the duties described and the certification presented.
Who Checks What: Issuing Administration, Flag State, and Port State
The issuing administration assesses competence and issues the COC. The flag state authorizes service on its ships through endorsement. Port state control verifies that documents exist and correspond to the crew's roles.
Each state in the chain has a distinct job. The issuing administration is responsible for the quality of certification: training approval, examination, assessment of competence, and issue of the COC. The flag administration of the ship takes responsibility for who serves on its vessels; when a mariner's COC comes from another Party, the flag state follows the recognition procedure and issues its endorsement. The two roles are related but not identical, and keeping them distinct is the point of the exercise.
Port state control sits at the verification end: inspectors visiting a foreign ship check that seafarers hold valid certificates and endorsements consistent with their positions. Use the state's role as a lens when you practice: if a stem concerns how a competency was assessed, the issuing administration matters; if it concerns permission to serve on a particular ship, the flag state matters; if it concerns a ship being inspected, port state verification is the frame. When a scenario names more than one state, decide which state's obligation the stem describes before answering — that decision is faster than rereading the stem.
Revalidation and Renewal: Keeping the Chain Current (Worked Scenario)
COCs are revalidated periodically — every five years under Regulation I/11 — subject to requirements such as medical fitness and continued professional competence. COPs for safety-related training follow their own refresher cycles. Track each document separately.
Worked scenario: A second officer holds a valid COC with a revalidation date two years away, and a basic safety training COP with a refresher due in four months. The employer schedules the officer's document review and the officer says no action is needed because the COC is valid for years. The mistake here is treating the COC's validity cycle as covering the COP. Revalidation of the COC and refresher training attached to a COP are separate requirements with separate triggers, and an expired safety-training COP undermines the very function the COC supports.
The better decision is a per-document review: the officer confirms the COC revalidation date, books the basic training refresher before expiry, and checks that the medical fitness certificate will remain valid through the upcoming tour. Why it matters: a valid COC does not substitute for a current COP on a required training element, and service on safety-critical duties depends on the whole chain being current — not on the central document alone. In practice items, always ask which document's clock the stem is describing.
Worked Scenario: Joining a Ship Flagged in Another Country
A COC issued by one Party does not by itself authorize service on a ship flagged by another Party. The mariner needs an endorsement from the flag state confirming recognition of the certificate before taking up the role.
Worked scenario: A marine engineer holds a COC issued by Country A and is offered a position on a tanker flagged in Country B. The joining date is set, travel is booked, and the engineer assumes the COC is sufficient because it is internationally recognized. The plausible mistake is stopping the trace at the issuing administration and never reaching the flag state. Under the recognition arrangement in Regulation I/10, the flag administration confirms the certificate and issues its endorsement, and that endorsement is what authorizes service on ships of that flag.
The better decision is to request the endorsement from the Country B administration before joining, allowing time for the application, and to carry both the COC and the endorsement onboard. Why it matters: during a port state inspection, the correspondence between each crew member's role and their flag-endorsed certificates is verified; a missing endorsement leaves the mariner's authorization to serve in question regardless of the underlying COC's quality. In scenario drills, train yourself to name every state in the chain — issuing, flag, and inspecting — and to place each document with its state.
Document Audit Exercise, Rubric, and an Adaptable Study Sequence
Run a one-page document audit on paper, score yourself against a rubric, then follow a four-step sequence: map the framework, drill definitions, work scenarios, and finish with mixed sets that force you to switch between document types.
Exercise: draw a table with columns for Document, Issuer, Function and Level, Validity Trigger, and What an Inspection Checks. Fill it for a COC, one safety-related COP, a flag-state endorsement, and a medical fitness certificate, using a paper scenario of your own construction — for example, a chief mate joining a foreign-flagged bulk carrier. Expected observations: endorsements never change what the COC says, they only connect it to a flag; COPs recur on their own cycles and must be tracked separately; the medical certificate is a gate that sits outside the COC entirely; and each document belongs to exactly one state in the chain.
Self-check rubric (learning milestones, not score predictions): you can define COC, COP, and endorsement in one sentence each without notes; you can decompose any scenario into function, level, and role; you can identify which state issues and which state checks each document; and you can explain the difference between revalidation of a COC and refresher training attached to a COP. Adaptable sequence: (1) two sessions mapping the Convention and Code structure, tagging facts as A or B; (2) two sessions on document definitions using the table format; (3) two sessions on scenarios, one per document type, written as the worked examples above; (4) mixed sets where stems switch documents mid-question. Readiness checks: complete a fresh audit from memory, explain both worked scenarios aloud in under two minutes each, and score your tagged flashcards until the A/B split is automatic. For administrative details such as application procedures, refer to your administering authority, for example the USCG National Maritime Center for US mariners.
- Audit five documents, not one: COC, COP, endorsement, medical, and the flag connection.
- Write scenarios yourself — a role, a flag, and a joining date create all the friction you need.
- Readiness is a described chain, not a memorized list: state the issuer, scope, and check for each document.
References and further reading
Use these references to explore the concepts and check the latest information from the relevant organizations.