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What is primary source verification (PSV) in maritime?

Last updated: 7 September 2026

By the Docka team · Reviewed 7 September 2026

Primary source verification (PSV) means asking the authority that issued the certificate (the flag state's official register) instead of trusting the PDF. Docka queries that register directly and returns a timestamped, PSC-ready result.

The rest of this page unpacks that sentence: what counts as a primary source, what does not, and why the same three letters mean a ship to half the industry.

Primary source, secondary source

A certificate of competency (CoC) in a seafarer's hand is a copy of a record. The record is the entry in the flag state's register. Everything printed on the paper, the expiry date included, is a claim about that entry.

The Danish Maritime Authority puts it plainly on its verification service: the STCW Convention requires that certificates and endorsements can be verified at the issuing administration. The administration is the primary source. A verification that stops at the paper, however careful, is a check of the copy.

Each authority decides what key opens its register. The Maritime and Coastguard Agency (MCA) wants a document ID and a date of birth. Cyprus wants the seafarer ID and the certificate number together. Denmark wants the certificate number alone. The method is the same; the key differs.

What primary source verification is not

• Reading the PDF, by eye or by OCR. That is transcription of the copy.
• Scanning a QR code that opens a PDF on a file host. Same copy, different route.
• Comparing the stamp and signature with a specimen. A good forgery is made to pass that test.
• Confirming with a training centre that it issued a course certificate. Useful, but the training centre is not the flag state, and Docka labels such a result one level below a government check.

PSV also means platform supply vessel

In shipping, PSV is the everyday abbreviation for a platform supply vessel, the offshore ship that carries cargo, fuel and drilling supplies out to rigs. This page is about the verification method, not the ship. If you searched for the vessel type, nothing here will help you; if you searched for how to check a seafarer's papers against the register, read on.

Because of the collision, Docka writes the phrase out in full before using the abbreviation, on every page.

How Docka does it

Docka queries eight flag-state registers directly: Estonia, Denmark, Cyprus, the United Kingdom, Norway, France, Ukraine's state registry and Azerbaijan. For Bulgaria the automatic check confirms that the document exists and nothing more. For every other country Docka opens the official portal, pre-fills what it can, and a person completes the check there. The registry coverage page lists each authority with its portal.

The result is labelled on a four-level ladder so nobody mistakes a weak check for a strong one:

• L0 Self-uploaded, not yet verified
• L1 Reviewed by staff
• L2 Registry-confirmed
• L3 Government-verified

Each answer is stamped with the time the register was asked, so a port state control (PSC) inspector sees when the check happened, as well as what it found. The mechanics are in how seafarer certificate verification actually works.

Frequently asked questions

Is primary source verification the same as certificate verification?

It is one method of it, the strict one. Certificate verification can mean anything from glancing at a stamp to phoning a training centre. Primary source verification means one thing: asking the authority that issued the document, through its own register.

Does a QR code on a certificate count as primary source verification?

Only when the code opens the issuing authority's own register. Estonia's validity check accepts a scan of the QR code printed on the document and answers from the register. A QR code that opens a PDF hosted anywhere else is a copy of a copy.

Can a seafarer run primary source verification on their own certificate?

Yes. The flag-state portals described on this site are public forms with no login. Docka is free for seafarers, so a seafarer can also keep the verified result on file and share it.

Is primary source verification possible for every flag state?

Not automatically. Docka checks eight flag-state registers live: Estonia, Denmark, Cyprus, the United Kingdom, Norway, France, Ukraine's state registry and Azerbaijan. For Bulgaria the automatic check confirms only that the document exists. For other countries Docka opens the official portal with what it knows and a person finishes the check.

What does PSV mean in shipping when it is not about verification?

Platform supply vessel, the offshore ship that carries cargo and supplies to rigs. The two uses share three letters and nothing else.