The third officer, also known as third mate or 3/M, is fourth-in-command and one of the licensed members on deck of a merchant ship. He reports directly to the Officer-of-the-Watch: either the first or second officer. On bigger vessels, a 3/M acts as co-navigator and - this depends on his level of experience - can be held responsible for the OOW at daytime.
The third mate is charged with a wide range of responsibilities, like emergency procedures and safety and awareness protocols. This highly depends on the type of the vessel. On most ships, the 3rd officer assists the Junior-Watch-Keeping-Officer, the OOW. Usually he is the ship's safety officer and watch stander. In this case, he informs the Master about the navigational progress and other relevant specifics, such as the ship’s location, speed and more. This means that the 3rd mate has to be familiar with the captain's standing and voyage plan.
IMO regulations stipulate that a qualified 3rd Officer - regardless of his country of origin - should at least speak English properly. There are good reasons for this: English makes it easier to read maps, nautical publications and charts, while it enables swift communication with other vessels, multilingual crew-members and coast stations. Therefore, some mastery of the Queen's language is crucial.
As soon as a ship sets its sails something can go wrong. In case of emergency any 3rd Officer needs to stay vigilant and well-prepared to execute a sound response plan. Needless to say that the 3rd mate has to understand internationally recognized distress signals and be conversant with the IMO Merchant Ship Search and Related Rescue Manual.
In an iminent situation, the third mate needs to be in position; being able to get hold of the situation. He certifies that panic or anxiety doesn't detoriate the situation. In cases of emergency, the third mate needs to be able to swiftly perform damage assessment, and most importantly, he knows how to act when someone needs to be rescued from the sea.
Throughout the voyage, the third mate has the task to ensure that the ship stays seaworthy. The 3rd Officer has to fully understand the trim, stress, mechanical stability of the ship as well as its construction. The mate should know what to do in cases of flooding, loss of buoyancy or when fire occurs. In all of these cases the third mate provides guidance, e.g., like when a man is overboard, or during a disease breakout or abandoning ship.
On larger vessels a third officer reports about the ship's direction, speed and the effects of the wind, sea tides and currents, and more. He also instructs the Helmsman in keeping track of all these and other external factors.
a.) Unlimited Officer of the Watch Certification and License.
b.) National Certificate of Maritime Competency, endorsed by the ship's Flag state.
c.) Diploma from an accredited maritime training institution or facility.
d.) Over one-year experience in the position of at least a Deck cadet.
e.) Good verbal and written command of English.
f.) Computer literate, being able to work with a few basic Windows O.S based programs.
The salary of a third mate ranges in the neighborhood of US $4500 and US $6300 per month, depending on the cruise line and vessel's country of operation.