Deck Rating AB or OS

Able Seaman (AB)
The deck rating AB or OS is required to work as a deckhand on seagoing vessels greater than 100 GRT.
The deck rating AB or OS is required to work as a deckhand on seagoing vessels greater than 100 GRT.

There are two deck rating AB or OS (Able Seaman and Ordinary Seaman). To clarify these are Merchant Mariner Credential (MMC) National Rating Endorsements. And seagoing vessels greater than 100 GRT require deckhands to hold rating endorsements. At the conclusion of this article you will know which deck rating AB or OS is for you.

It must be stated that Master or Mate is not the same AB. While the Master or Mate may have the knowledge and skills to serve as AB. Unless their MMC says AB they may not legally serve as AB. However, the same experience used for Master or Mate may also be used to qualify for AB.

Deck Rating AB or OS: Able Seaman (AB)

Able Seaman (AB) is for experienced sailors. That is to say to qualify for AB the mariner must document their sea service experience. And, in addition, they must demonstrate knowledge of seamanship terminology and skills by passing both written and practical exams. Lastly, the AB must also hold the rating of Lifeboatman; or Lifeboatman-limited.

There are several AB ratings. And since all AB exams are the same, a mariner may advance to a superior AB rating by documenting sea service experience alone.

  1. Unlimited (AB Unlimited) requires 1080-days (3-years) of experience on seagoing vessels. And may serve as AB on any size or type of vessel.
  2. Limited (AB Limited) requires 540-days (18-months) of experience on seagoing vessels greater than 100 GRT. And may serve as AB on any type of vessel less than 1600 GRT.
  3. Special (AB Special) requires 360-days (1-year) of experience on any type or size of vessel on ocean or any navigable waters. And may serve as AB on any type of vessel less than 500 GRT.
  4. Offshore Supply Vessel (AB OSV) requires 180-days of experience. And they may serve as AB on any oil industry vessel.
  5. Fishing (AB Fishing) requires 180-days of experience. And may serve as AB on any fishing industry vessel.
  6. Sail (AB Sail) requires 180-days of experience on sail or auxiliary sail vessel. And may serve as AB on any sail or auxiliary sail vessel.

Columbia Pacific (ColPac) Maritime offers a 5-day ($700) AB course. However we do not offer Lifeboatman courses. For Lifeboatman we recommend the following schools. Both offer AB courses in addition to Lifeboatman.

Compass Courses in Edmonds, Washington.

Seafarers Worldwide in Anacortes, Washington.

Deck Rating AB or OS: Ordinary Seaman (OS)

Ordinary Seaman (OS) is an entry level rating endorsement. That is to say, it is an apprentice rating. Consequently there are no sea service or exam requirements. Follow the steps listed to get an OS.

Firstly, enroll in the TWIC (Transportation Workers Identification Program) program. Most importantly, print and save your receipt.

Secondly, complete Coast Guard form 719KE, Application for a Medical Certificate Short Form. That is to say, follow the instructions to complete the applicants portion. And then have the medical practitioner review and complete the form.

Thirdly, use Coast Guard form 719P DOT/USCG Periodic Drug Testing Form to get a DOT/USCG drug screening.

Fourthly, pay the Coast Guard evaluation and issuance fees of $145 at the Gov.Pay website. Most importantly print and save your receipt.

Fifthly, complete Coast Guard form 719B Application for a Merchant Mariner Credential. That is to say, follow the instructions exactly as written. When completing Section II be sure and check the box for a the original issue of an entry level rating. And then write in OS as the description.

Lastly, scan all forms and receipts. And then email them to a US Coast Guard Regional Exam Center (REC).

Email Instructions

Locate an REC near you

Conclusion

In conclusion the OS is an entry level apprentice rating. While the AB is a journeyman rating. In contrast, holding a Master or Mate does not qualify you as an AB. Your MMC must say AB to work as a deckhand on seagoing vessels 100 GRT and greater. The biggest mistake that a mariner can make is NOT getting an AB. The result being that too many career opportunities are missed without it.

Please contact us if you have any questions. Columbia Pacific (ColPac) Maritime is here to help you meet your professional maritime goals.