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Ship & Crew



SEA’s Guide to USCG Endorsements – Introduction
Entry-Level Mariners: OS, AB, RFPNW, Lifeboatman/PSC
Getting a Mate/Master Endorsement
Completing Practical Assessments (for STCW endorsements)
Steps to Apply for a Merchant Mariner Credential (MMC)
Testing for your endorsement

SEA’s Guide to USCG Endorsements – Introduction

The process to earn USCG credentials has become more complicated over the past few years as the US works to align domestic licensing with international standards (referred to as Standards of Training, Certification, and Watchkeeping, or STCW) .

For a long time, mariners applied for “Licenses,” but recently the Coast Guard shifted vocabulary.  Now, mariners are issued a red passport-sized book called a “Merchant Mariner Credential,” in which are printed various endorsements:

  • Deck Department Officer Endorsements include the title of Mate or Captain for domestic routes (National), and Officer in Charge of Navigational Watch or Master (Management level) for international routes (STCW).
  • Deck Department Rating Endorsements include Ordinary Seaman and Able Seaman for domestic routes (National), and Rating Forming Part of a Navigational Watch (RFPNW) and Able Seafarer–Deck (AS-D) for international routes (STCW).
  • Engine Department Officer Endorsements include Designated Duty Engineer and Chief Engineer (HP indicates domestic, while kW indicates international)
  • Engine Department Rating Endorsements include RFPEW (international) and Qualified Member of the Engine Department (QMED) (Domestic and/or International).

Because the USCG continues to make changes and additions as it works to implement STCW regulations, online links and resources may change. You should always do your own research on the National Maritime Center website for the latest information. If any of the links on this page are broken, it may be because the USCG has updated their pages. Use a search engine to find the updated document or website. Please let the SEA Marine Department know if you find a broken link or if you have updated information you would like to share:

National Maritime Center Checklists
For each endorsement that is issued by the USCG, there is a checklist that details all of the requirements for that endorsement. These checklists are used by the USCG evaluation team when they look at your credentials. The USCG makes these checklists available on the National Maritime Center website under the “Checklists” tab. You should look through these checklists to find out what endorsements you qualify for.

Entry-Level Mariners: OS, AB, RFPNW, Lifeboatman/PSC

The most basic credential you can apply for is Ordinary Seaman / Wiper (OS is a deck rating, and Wiper is an engine rating). OS/Wiper requires no sea service. This is a national rating endorsement, which means you can only use it in domestic waters. The STCW equivalent (allowing you to sail internationally) requires a few extra steps (you will find this is always the case, as international regulations are more stringent than US regulations). The STCW equivalent is called Rating Forming Part of a Navigational Watch, or RFPNW. The RFPNW endorsement requires the following:

  • 180 days of sea service
  • USCG approved Basic Training course
  • Skills Assessments that you can do onboard with your captain or mate.

The next level of credential is a national Able Seaman (AB) and an international Able Seafarer – Deck (AS-D). There are various levels of national AB that you can earn depending on how much sea service you have:

  • AB Sail – 180 Days
  • AB Special – 360 Days
  • AB Limited – 540 Days
  • AB Unlimited – 1080 Days

As you can see, the level of AB depends on your experience. If you have 540 days, apply for the AB Limited! It’s a higher level of qualification than the AB Sail. You can still use it to work as an AB on a sailboat. Any of these AB’s qualify a mariner to work on the SEA vessels in the capacity of and AB, including AB Sail. Besides the sea service requirement, you must also qualify as Lifeboatman or Lifeboatman-Limited (also referred to as Proficiency in Survival Craft) .

The international AS-D requires 540 days of sea service as well as already hold the RFPNW rating (before you start to earn your 540 days). In addition, you must have Proficiency in Survival Craft (limited or full).

Lifeboatman / PSC
This endorsement requires that you have experience dealing with abandon ship equipment including life rafts and lifeboats.  Lifeboatman is the domestic term for the endorsement, while PSC is the international term. It’s the same qualification in this case though. The full lifeboatman/PSC endorsement requires taking a training course. The full endorsement means you can work on vessels equipped with gravity-davit launched lifeboats and requires 180 days of sea service (and the course). Meanwhile, the limited endorsement restricts mariners from working on ships with those large lifeboats but is a suitable endorsement for working on the SEA vessels (and every other tall ship in the fleet). The limited endorsement can be earned by completing practical assessments, taking a test at the Regional Exam Center, and having 360 days of sea service. There is a checklist on the NMC website for Lifeboatman and Lifeboatman Limited.

Getting a Mate/Master Endorsement

Officer endorsements are determined by the tonnage of the vessels you have sea service on as well as the waters that you sailed on (Great Lakes, Inland, Near Coastal or Oceans). To work for SEA as a mate, you will need a national (domestic) Near Coastal Mate 200 Ton at minimum. Combine this officer endorsement with an AB (domestic) and RFPNW (international) to maximize your qualifications.

As you work to upgrade your MMC, you can move up to Oceans with the STCW endorsement of Officer in Charge of a Navigational Watch (OICNW). This endorsement requires completion of extensive coursework (Medical First Aid Provider, Watchkeeping, Advanced Firefighting, PSC or PSC-Limited, Visual Signaling, Bridge Resource Management and Leadership and Teamworking Skills), as well as practical assessments and sea service requirements. The National 200 Ton Ocean Mate with OICNW <500 GRT is a recommended route given that the coursework is much less than increasing in scope greater than 500 GRT on the international level. This blog by Bluewater Maritime Consulting offers a detailed look at the 200 Ton with OICNW <500 GRT.

Completing Practical Assessments (for STCW endorsements)

If you are applying for an international rating, you will need to complete the STCW assessments for RFPNW (watch standing) and PSC (lifeboats). Each of these forms needs to be filled out by a mate or captain on a boat you have been working on. Many mariners already have this filled out in anticipation of submitting an application for a credential. If you have not completed the assessments yet, you will have to contact a previous employer to see if they can assess you or have them completed at your current position.

Steps to Apply for a Merchant Mariner Credential (MMC)

Apply for a TWIC card
Get a physical using form CG-719K
Pay application, exam and issuance Fees
Complete a drug screen
Complete application form CG-719B
Provide letters of Sea Service
Submit all materials to your Regional Exam Center as an “application package”

Apply for a TWIC card

  1. To apply for a TWIC Card, complete this online application. As part of the application, you will be asked to schedule an in-person appointment and will be given a list of TWIC centers to choose from in your area. You only need a TWIC card for your first application. If you are renewing or upgrading, your TWIC card can be expired.
  2. At your appointment, you will need to provide required documentation, be fingerprinted and take a facial photo. The cost for a TWIC card is$125.25, valid for five years.
  3. You can submit your application package before you receive your TWIC card. If you choose to do this, you must include a copy of the paperwork given to you at the TWIC center following your in-person appointment to prove you have completed this step. If you have your TWIC card in-hand, submit a photocopy of the card with your application.

Get a physical using form CG-719K

  1. Here is the link to the current USCG Application for Merchant Mariner Medical Certificate.
  2. Concentra, an occupational health clinic with locations around the US, will complete the physical for about $100. If you decide to go to your own doctor, make sure they are able to perform the vision and hearing tests.
  3. On the NMC website you can find a list of errors commonly made on the medical form. If you send your form in with errors, it will delay the processing of your application
  4. Submitting your completed form: The NMC very recently (2018) created a method to submit the medical form directly to the medical evaluation team. When your Medical form is complete, email it to . Include your full name in the subject line and make sure all attachments are in PDF format. Do not submit any other parts of your application to this address (sea service, drug test letter, etc). This will all go together to a different email address.

Pay application, exam and issuance Fees

  1. Visit
  2. Go to “Common Payments” on the right side of the page, then choose USCG Merchant Mariner User Fee Payment.
  3. Fill out the payment form, selecting the type of endorsement that you are applying for. You can choose to pay for all fees at once or wait to pay for your exam and issuance fees later.

Complete a drug screen

  1. If you are drug tested because you are an employee or volunteer on a boat, ask for a letter from the company or organization that states you are part of a USCG approved testing program.
  2. If you are not already part of a drug testing program, you can go get tested at a facility such as Concentra or Labcorp. Bring the Coast Guard’s Periodic Drug Testing Form GC-719P.

Complete application form CG-719B

  1. Print or download the Application for Merchant Mariner Credential Form CG-719B
  2. Instructions for how to complete this form are on the first three pages of the form itself. In addition, the National Maritime Center has a helpful YouTube video on how to fill out the form.
  3. If this is your first time applying for an MMC, you will need to take the Mariner’s Oath in front of a certified witness. This can be any Notary Public (banks often have this service), or you can take the oath at a Regional Exam Center. The same person who witnesses your oath also needs to witness you signing the application form on page 5 so wait to sign until you are present at the Notary Public or REC.
  4. In the section that asks if you’d like to include a “Third Party,” it is recommended that you list someone here who can help move your application along in the case that you are at sea or otherwise unable to contact the Coast Guard yourself. By selecting someone to act on behalf of you, you are giving them permission to call the Coast Guard to talk about your application.

Provide letters of Sea Service

  1. If you have sailed on the Robert C. Seamans or Corwith Cramer, request a sea service letter from SEA here.
  2. If you were an employee or volunteer for a boat, ask the owner or company for a sea service letter. It is recommended that you ask for this before leaving the vessel at the end of the season/contract.
  3. If you have time on a privately owned boat, including a boat you own yourself, you can document it using the Small Vessel Sea Service Form CG-719S

Submit all materials to your Regional Exam Center as an “application package”

  1. Select a Regional Exam Center (you can find REC locations and email addresses on the National Maritime Center website). You don’t have to go into the REC to submit your application – you can do it online!
  2. Email your application to the REC that you chose: Include a copy of your TWIC, TWIC application receipt, or TWIC exemption statement in your e-mail attachment(s).
  3. User fees (if applicable) must be paid using Include a copy of your user fee receipt in your e-mail attachment(s).
  4. Completed applications must be scanned at a resolution not exceeding 300 dpi, saved in PDF format, and cannot exceed 8 MB in size. If e-mail size (including attachments) exceeds 8 MB, send documents in multiple e-mails.
  5. The subject line of your e-mail must be: Last name, First name, Middle name, mariner reference number. NOTE: New applicants will not have a reference number.
  6. Ensure all attachments are included, then send. Please use the minimum number of e-mails to send your application and attachments.

Testing for your endorsement

After you apply for your rating or officer endorsement, the NMC will review your application. Once approved, they will send you a “letter to test.” This letter will list all of the tests that you are required to take. You can choose to take these tests at a Regional Exam Center (REC) or you can take a USCG approved class and earn certificates to submit to the Coast Guard (if you choose this route, you can send your certificates in with your application). If you choose to study on your own and test at the REC, here are some resources to get you started:

  • National Maritime Center Examinations Page – here you will find links to a list of reference material for studying, a list of books that are provided in the exam room, and a sample exam for each topic you might see on your letter to test.
  • Get Your Captain’s License, by Charlie Wing – This book is the perfect resource for self-study for the 100 Ton level, and paired with a few additional resources, works great to study for the 200 Ton and AB as well.
  • Upgrade U – This app costs about $30. It has test questions for all levels of licensing and works off-line so you can take it to sea.
  • LAPWARE – this is an online study program that is one of the most commonly recommended for upper level (Oceans) studying. This program includes solutions for diagrams and math problems so that you can learn how to solve these problems.
  • – This is another online study program that’s widely used.
  • Navigation Rules - This is a PDF of the Rules of the Road book. All levels and types of endorsements require you to know the Rules of the Road and it’s recommended that you actually read the book, not just run through multiple choice quizzes.
  • Nav Rules app by Mintaka Innovations – this Rules of the Road study app includes the Rules of the Road book so that you can review the actual book when you miss questions.
  • Seamanship Techniques by D.J. House – This book was written for international ratings and officers but is a great overview of the information needed to pass the AB exams.