A second mate or second officer (2/O) is a licensed member of the deck department of a merchant ship holding a Second Mates Certificate of Competence, by an authorised governing state of the International Maritime Organization (IMO). The second mate is the third in command and a watchkeeping officer, customarily the ship's navigator. Other duties vary, but the second mate is often the medical officer and in charge of maintaining distress signaling equipment. On oil tankers, the second mate usually assists the chief mate with the cargo operations.
While a ship is under way, the officers navigate it, typically in three shifts or watches.
Mates were in high demand during World War II.
2nd Mate of a cargo ship of the NDL, 1966. During this time, he was responsible for all freight operation of the cargo freighter
A second mate must have a number of qualifications, including a license.
A licensed mariner is a sailor who holds a license from a maritime authority to hold senior officer-level positions aboard ships, boats, and similar vessels. Qualification standards for licensed mariners are universally set by the STCW Convention adopted and promulgated by the International Maritime Organization (IMO), while the licenses of individual sailors are issued by the delegated maritime authorities of the member states of the IMO; these may vary in the details of the implementation, including the government agency responsible for licensing and the local names of the grades and qualifications in each particular country.
A sample United States Merchant Marine license issued by the United States Coast Guard in 2006
Mariners (Captain, first officer and second officer) at the controls of the Kristina Regina
