The Seafarer Medical Examination and the Certificate of

A seafarer's pre-joining medical examination is a structured check of vision, colour vision, hearing, chest, heart and blood, and the certificate of fitness that follows is signed by an approved doctor. The examination is judged on what it measures, not on a general opinion, and the certificate states any limitation in plain terms. The sections below set out what each part looks for, what imaging adds, and how long the document remains valid. How such images are produced and interpreted is described in plain language on inside the scanner, which covers the difference between a shadow on a film and a computed cross-section.

What the examination checks

The examination is built around the tasks a seafarer performs on board: keeping a lookout, reading gauges and alarms, hearing instructions over machinery noise, and working in enclosed or remote spaces where a sudden incapacity endangers others as well as the person concerned.

Vision is recorded as distance acuity for each eye, with and without correction, and near vision for reading charts and labels. Colour vision is tested separately, because navigation lights, pipe markings and alarm indicators depend on distinguishing red from green. Hearing is measured by audiometry across the speech frequencies, and the result is compared with a threshold rather than with the examiner's impression. The chest is examined by auscultation and by history of previous disease. The heart is assessed by pulse, rhythm, blood pressure and history of cardiac events. Blood and urine tests screen for anaemia, diabetes and kidney function. Height, weight and, where relevant, body mass index are recorded.

The pattern is the same throughout: a measurement is taken, a threshold is applied, and the result is written down. A finding that falls outside the threshold does not automatically end a career at sea, but it must be addressed before the certificate is issued.

What does the chest X-ray in a seafarer's medical examination look for?

The chest X-ray looks for active pulmonary tuberculosis and for other significant lung or heart shadowing that a consultation alone would not reveal. It is a screening image, not a diagnostic report, and it is read for patterns that matter at sea: consolidation, cavitation, effusion, an enlarged heart silhouette, or evidence of previous disease that has left scarring.

Imaging is used instead of consultation alone when the history or the examination raises a question that cannot be answered by listening and asking. A seafarer with a persistent cough, a history of tuberculosis, a positive skin or blood test, or a recent stay in a high-incidence area may be sent for a chest film even when the chest sounds clear. The same applies where an employer or a flag state requires a baseline image at defined intervals. A clear chest on auscultation does not exclude a small lesion, and a film does not replace the clinical assessment; the two are read together.

What an ECG adds to the examination

An electrocardiogram records the electrical activity of the heart over a short period and is used when the pulse is irregular, when there is a history of chest pain, fainting or palpitations, or when the seafarer is above a certain age set by the administering authority. It detects rhythm disturbances and conduction defects, and it can show evidence of a previous myocardial infarction that the seafarer did not report.

An ECG is a tracing, not a diagnosis. A normal tracing does not exclude structural heart disease, and an abnormal one may be a normal variant for that person. The value of the test lies in comparison: a tracing taken now can be set against one taken at the next renewal, and a change over time is more informative than a single record. Where the tracing is abnormal, the case is usually referred to a cardiologist before the certificate is decided.

Who signs a certificate of fitness?

A certificate of fitness is signed by a doctor approved by the flag state or by the administration that issues the seafarer's documents. In the United Kingdom the approved doctor works under the maritime medical standards set by the Maritime and Coastguard Agency, and the certificate is issued on the approved form. The signature is personal: it certifies that the holder has been examined against the published standards on the date shown, and it is not a general statement of good health.

The certificate normally carries the seafarer's identity details, the date of examination, the date of expiry, and any limitation. It is valid for a defined period, commonly two years for a seafarer under a certain age and one year above it, though the exact period depends on the issuing administration and on the outcome of the examination. A certificate issued after a restricted examination, or one that requires review, may be valid for a shorter time.

What does a limitation on the certificate actually restrict?

A limitation restricts the duties or the conditions under which the holder may serve, and it is written so that a master or a crewing office can apply it without interpreting a medical opinion. Typical limitations concern vision without corrective lenses, service in a particular department, the carriage of a specific medical supply, or the need for a review before a stated date.

A limitation is not a bar to employment. It is a condition attached to the certificate, and it travels with the document. A seafarer cleared only with corrective lenses must wear them on watch; one restricted from solo watchkeeping must be paired. The limitation is read at the same time as the certificate, and a certificate presented without its limitation, or after its expiry date, is not valid.

How long the certificate lasts and what renewal involves

The certificate expires on the date printed on it, and a seafarer cannot sign on after that date without a new examination. Renewal repeats the core checks: vision, colour vision, hearing, chest, heart and blood, with imaging or an ECG added where the standards or the history require it. A renewal is not a formality; a change in vision, hearing or cardiac status since the previous examination is exactly what the process is designed to catch.

Where a seafarer has been ill or injured between examinations, the approved doctor may require a shorter validity or a specific review. The certificate is a working document, and its dates and limitations are as important as the signature.

Why the measurements matter more than the opinion

The examination is a set of measurements against published thresholds, and the certificate is the record of those measurements. A seafarer who understands what is being tested, and what a limitation means in practice, can prepare for the examination and can read the certificate without ambiguity. The document does not describe a person; it states what that person has been cleared to do, until a stated date, under stated conditions.