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What is a Continuous Discharge Certificate (CDC) or Seaman’s book?

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Does your dream job involve working on a ship? If yes, one of the most important documents you will need is a Continuous Discharge Certificate (CDC). This document speaks volumes about your professional life at sea and records your journey as a seafarer.

Commonly referred to as a Seaman’s Book, the CDC is often described as a “passport for the sea” — not because it replaces a passport, but because of how essential it is for anyone working onboard a merchant vessel. This article explains what a CDC (or Seaman’s Book) is, what purpose it serves, and why it remains a critical document for seafarers worldwide.

What is a Continuous Discharge Certificate (CDC), and what purpose does it serve?

A Continuous Discharge Certificate (CDC) is an official sea service record document issued by the maritime administration of a country. It certifies a person’s status as a seafarer and maintains a continuous, verifiable record of their service at sea.

In India, the CDC is issued by the Shipping Master under the authority of the Directorate General of Shipping (DG Shipping).

This document primarily serves two important functions:

1. Proof of Seafarer Status

The CDC establishes that the holder is a recognized seafarer under the flag state’s maritime system. It contains essential personal details such as the seafarer’s name, date of birth, nationality, CDC number, and other identifying particulars.

While it confirms a person’s status as a seafarer, compliance with STCW requirements is demonstrated through valid STCW certificates, not by the CDC itself.

2. Continuous Record of Sea Service

The CDC functions as an official service record. Each time a seafarer joins or leaves a vessel, the ship’s Master records the engagement and discharge in the CDC. These entries typically include the vessel’s name and details, the seafarer’s rank, dates of joining and signing off, and voyage information.

Over time, this creates an authoritative and verifiable history of a seafarer’s career at sea, which is essential for promotions, certification upgrades, and employment verification.

Additionally, in most countries (with the notable exception of the United States), a valid CDC allows seafarers to go ashore without requiring a separate visa, thereby facilitating shore leave when a ship calls at port.

Are Continuous Discharge Certificates (CDCs) and Seaman’s Books separate documents?

The short answer is no — in most maritime administrations, they are not separate documents.

In countries such as India, the UK, and the Philippines, the terms “CDC” and “Seaman’s Book” are commonly used interchangeably to refer to the same sea service record document. The term Seaman’s Book is widely used because the document records every discharge (sign-off) and engagement throughout a seafarer’s career.

More than just an official booklet, a CDC represents a seafarer’s professional life at sea. It is not a travel document like a passport, but it is legally required for working onboard merchant ships under most flag states.

Why is a Continuous Discharge Certificate (CDC) needed?

Internationally, there was no single convention that explicitly mandated a CDC until the introduction of the Seafarers’ Identity Documents Convention, 2003 (ILO C185).

Before ILO C185, different international conventions required seafarers to be provided with:

An identity document (ILO Convention No. 108)
A service record document (ILO Conventions No. 22 and No. 23)
Documentation supporting port state control and welfare standards (ILO Convention No. 147)

To meet these combined requirements, maritime administrations worldwide adopted the practice of issuing a single document that functioned as a continuous service record — leading to the widespread use of the CDC.

With the adoption of ILO C185, the international community moved towards issuing dedicated Seafarer Identity Documents (SID), separate from service record books. As a result, many countries — including India — now issue separate identity documents, while the CDC continues to serve as the official record of sea service.

In India, the use and issuance of a Continuous Discharge Certificate (CDC) is governed under the Merchant Shipping Act, 1958 and the relevant Merchant Shipping (Continuous Discharge Certificate) Rules, administered by the Directorate General of Shipping. Seafarer identity verification is now handled separately through the Biometric Seafarer Identity Document (BSID).

Conclusion

For anyone aspiring to build a career at sea, a CDC remains an essential document, alongside a valid passport and Seafarer Identity Document. It is the official record of your time at sea and a key requirement for employment, career progression, and certification in the maritime industry.

To apply for a CDC, a seafarer must complete the mandatory STCW basic safety courses and meet the eligibility criteria prescribed by the maritime administration.

If you would like to understand how to apply for a CDC or need guidance on the application process, documents required, or common mistakes to avoid, you can read our subsequent articles.

This Blog is authored by Akshay Shrivastav

Details about the Author

Akshay Shrivastav holds a Bachelor's degree in Nautical Science from Indian Maritime University, complemented by pre-sea training at the International Maritime Institute. He currently serves as a Navigation and Operations Officer at Anglo-Eastern, managing ship navigation, cargo operations, and logistics with expertise in vessel oversight, tank cleaning coordination, and safety compliance during loading and unloading. At Anglo-Eastern, Akshay Shrivastav collaborates with teams to command vessels, streamline maritime operations, and assist senior officers in preparing for inspections and audits to uphold top standards. Driven by safety and precision, he seeks to apply a structured, detail-focused mindset to drive organizational success, while promoting teamwork and operational efficiency.

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