An Able Seaman is also called an Able-Bodied Seaman. This is probably the reason the initials commonly used for able seaman are “AB” rather than “AS.” An Able Seaman has more knowledge and experience than an Ordinary Seaman (OS). The differentiation between the titles “Able Seaman” and “Ordinary Seaman” first occurred in the mid 1800s as a means of creating pay scales. Able Seamen were paid about 25% more than Ordinary Seamen in the Merchant Marines. The Merchant Marines refers to a country's commercial ships that are both publicly and privately owned.
A Merchant Seaman in the United States Merchant Marines must have a Merchant Mariner's Document (MMD), also called a Z-card, issued by the United States Coast Guard. The MMD will have the merchant mariner's “endorsement,” or list of positions he/she is qualified to hold, printed on the back of the document. Able Seaman is one of many endorsements a mariner could hold.
The number of Able Seamen who are required by the US Coast Guard to be employed on a ship depends greatly on the size of the ship. As few as three or as many as ten Able Seamen may be required to legally operate a US flagged merchant ship. If a ship is caught operating without the proper number of Able Seamen, or of any other position, it will be “arrested,” fined, and not permitted to leave port until it has a sufficient crew for its size.
An Able Seaman's job typically includes standing a navigation watch on the bridge, or wheelhouse, of the ship, assisting the deck officer on watch by steering the ship according to the deck officer's instructions. On his off-watch hours, he may be required to perform routine maintenance; painting, cleaning, repairs to ship's deck equipment, or any other tasks that deck officers see fit for him to do.
The life of a merchant marine is a difficult one to choose. Many Able Seamen have difficulty balancing their family and work lives, as they can be at sea for much of the year. It is also a dangerous job, and the wages are generally less than the working conditions may warrant. However, a love of the sea draws people back, convincing them to work as Able Seamen, or a variety of other positions upon a merchant ship.