Able Seaman (AB)

Able Seaman (AB)
Able Seaman (AB) is a USCG rating required for deckhands on most seagoing boats over 100 GRT. More importantly, getting the AB is about learning traditional seamanship skills.

Able Seaman (AB)

Able Seaman (AB), is an MMC Rating issued by the USCG. More important, most seagoing vessels greater than 100 GRT need their crew to have an AB. To get an AB the mariner must: Firstly, have sea time on boats. And secondly, complete an approved AB course.

On the other hand, if you don’t have sea time, apply for an OS. To clarify, the OS is an entry level rating. With this rating you can get an entry level job to gain experience.

Which is for you: AB or OS?

Able Seaman (AB): Level & Sea time

There are six AB ratings. Each is a different level. The higher the level, the more vessels the AB is qualified to work on. To explain, AB levels are based on the mariners sea time only. Therefor, advancement to a higher level AB is base of sea time alone.

The highest level is AB Unlimited. This AB requires 1080-days of sea time, on oceans. And, additionally can work on any type of size vessel.

AB Limited is one level lower. This AB requires 540-days of sea time, on oceans. And, can work on any type of vessel less than 1600 GRT.

One level lower is AB Special. This AB requires 360-days sea time on ocean, or navigable inland waters. Additionally, this AB can work on any type of vessel less than 500 GRT. To clarify, this AB is good for any towing vessel.

AB Fishing, AB Offshore Supply Vessel (OSV), and AB Sail are the lowest AB level. Each requiring only 180-days of sea time. And additionally, limited to one type of vessel.

Able Seaman Checklist >>


The AB must skilled in the use of survival craft. Therefore, the AB must also have a rater of either: Lifeboatman, or Lifeboatman Limited. To explain: Firstly, Lifeboatman is for vessels with any type of survival craft. And secondly, Lifeboatman Limited is for vessels with life-rafts only.

Lifeboatman Checklist >>

ColPac does not offer either course at this time. But, we do recommend two schools, both offer AB courses too:

Compass Courses in Edmonds, Washington.

Seafarers Worldwide in Anacortes, Washington.

Able Seaman (AB): Course

5-days / $700

This approved course will satisfy the exams for any level of AB.

Course Schedule

Call 503-841-6066 for more schedule options.

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Feb 7 AB


Mar 21 AB


More Info

Sea Service Bench Mark Checklist

Frequently Asked License Questions

Use your AB sea time to get a captain license:

Master or Mate 100 and 200-ton

Apprentice Mate (steersman) of Towing.

Master or Mate of Fishing 500 to 5,000-ton.