How to Become an Ordinary Seaman (OS): Your Guide to a Starting a Maritime Career

The maritime industry offers a rewarding career path, and the first step aboard a large vessel for many aspiring mariners is becoming an Ordinary Seaman (OS), also known as an Ordinary Seafarer. The OS rating is the foundational, entry-level position that requires no prior sea experience, making it the perfect starting point for your maritime career and eventually earning an Able Seaman credential.

Here is a comprehensive guide to understanding the role and securing your Ordinary Seaman rating.

What is an Ordinary Seaman (OS)?

An Ordinary Seaman holds the lowest unlicensed rating on a ship. This is a vital position that provides essential support to the deck department. While the work can be demanding, it is the crucial training ground where you learn the ropes of the seafaring trade.

Ordinary Seaman Duties and Responsibilities often include:

General Maintenance: Assisting with the upkeep of the ship’s structure and equipment.
Cleaning and Sanitizing: Keeping communal and working areas clean and orderly.
Painting and Scaling: Performing chipping, scaling, and painting work to prevent corrosion.
Cargo Handling: Assisting with the loading, unloading, and securing of cargo.
Watch Duties: Standing lookout and performing general deckhand tasks as directed by superiors.

This role provides hands-on experience that is essential for progressing your career and earning the sea service needed for higher ratings. Again, although the work can be demanding, it can be a lot of fun and is a stepping stone in the industry!

The First Step: Obtaining Your Merchant Mariner Credential (MMC)

Before you can work on most commercial vessels in the United States, your first goal must be to secure a valid U.S. Merchant Mariner Credential (MMC) from the National Maritime Center (NMC) which is part of the U.S. Coast Guard (USCG). This credential serves as your professional maritime license, and the Ordinary Seaman rating is included in your MMC.

To obtain your entry-level MMC, you must meet the below criteria.

6 Essential Requirements for Your Entry-Level MMC:

Citizenship Status: You must be a U.S. Citizen or an alien admitted for permanent residence.
TWIC Card: You must hold or have applied for a Transportation Worker Identification Credential (TWIC).
Age Requirement: You must be at least 16 years old (applicants under 18 require parental or guardian consent).
Drug Testing: You must pass a drug test administered within the last six months (documented on Form CG-719P).
Medical Certificate: You must hold or be approved for a USCG Medical Certificate (Form CG-719K or CG-719KE), demonstrating you are fit for duty.
Application Fees: You must pay the required Mariner’s Fees via the designated government payment site (Pay.gov).

Once you have completed these pre-requisites, the final step is to complete and submit the USCG MMC application form, CG-719B.

Sea Service and Endorsements

How many Sea Days are needed apply for an Ordinary Seaman credential?

The good news is that there are no sea service requirements for the OS endorsement. This means you can secure your MMC and break into the industry without any prior maritime work experience.

What Endorsements are Included in an Entry Level Rating?

When you successfully apply for an entry-level MMC, you will receive several key endorsements, which include:

Ordinary Seafarer (OS)
Wiper (The entry-level position in the engine department)
Steward’s Department (FH) (Food Handler/Messman duties)

These ratings allow you to work in various capacities on a vessel, opening up a wider range of job opportunities as you begin your career.

Setting Sail on Your Career

Getting your Ordinary Seaman rating is the critical first step in starting a career at sea. While securing your MMC is not a guarantee of employment, it is essential as it proves you are certified and eligible to work in the professional maritime industry. Once you have your MMC in hand, you are ready to start searching for your first opportunity. Once you have some experience under your belt, you’ll be able to advance your career by earning credentials like Able Seafarer (aka Able Seaman).