Ships have probably always had someone designated as “second in command”. From the first Sea People through the Roman fleets to the Barbary galleys, there was someone to fall back on should the Captain lose his wits, succumb to illness or fall in battle. When Columbus set out to find his passage to India his second would have been known as a master aboard ship and would have had the duties later divided into the purview of three or four men. He was First Lieutenant, quartermast/purser and bosun all in one.
As the great age of sail dawned and ships, along with their companies, grew ever larger, responsibility had to be delegated. The purser began to control the stores, the master became the expert navigator, the bosun looked after the men and so on. The Lieutenant, though, remained second in command and that tradition was almost universal in European and American navies by the 18th century.
The Royal Navy in its Golden Age took stratification of rank to the highest degree. A ship of the line could carry multiple Lieutenants, each in charge of their own gun crews and a division of up to 100 men. Aside from the First Lieutenant, they also took command during certain watches, particularly at night. This put a lot on the shoulders of sometimes very young men, but the Navy had its own way of separating the wheat from the chaff when it came to leaders. No one who held the title of Lieutenant had avoided the dreaded Examination.
Much like that rite of passage for modern teenagers, the driver’s test, Examination for Lieutenant was a cause for much anxiety and potential elation or despair among the population of Midshipmen. The test was taken in two parts. One was a written piece and the other was entirely oral with the young man standing before a board of officers with a rank no lower than Captain and quizzed until the board was satisfied. In his engrossing book Jack Aubrey Commands, An Historical Companion to the World of Patrick O'Brian, Brian Lavery gives a few sample questions from this particularly feared portion of the test and just looking at them hints at how difficult passing must have been:
You are sent in a ship ordered to be fitted out, the Captain not having appeared; the lower masts and bowsprist are in but not rigged: What part of the rigging goes first over the mast heads?
Upon receiving orders to sail from Spithead with a south-east wind, at what time of tide will you begin to unmoore that you may have the advantage of it in plying down to St. Helens?
Your sails are still all set; the wind beings to freshen. What sails will you take in first?
There were also questions about altitude, amplitude, bearings and distances that would certainly make even the most knowledgeable seaman question his abilities at some point. The board knew how the young man had done on his written examination so there was no mincing words at the end of the oral portion. Much like the teenager at the DMV, a man was either congratulated for his capabilities and handed his Lieutenancy, or told he failed. In the latter instance, a Mid could take the examination all over again in six months.
Aboard a successful privateer, good Lieutenants were in high demand. Since the very nature of privateering necessitated having men who could command prize crews, more than one Lieutenant aboard was the norm. Given the fact that more men passed the examinations of many navies than there were positions for, it was not uncommon for good men to sign up on a privateer and make their way at sea in a less formal manner. The chances for actual command were almost guaranteed as well. Sooner or later a prize would be caught and, if the ship was seaworthy, she would most likely be sent back to the privateer’s home port for libel with a Lieutenant at her helm. Under a successful Captain it was lucrative work; men like Francis Drake, Jean Bart, John Paul Jones and Renato Beluche made it worth their First Lieutenants’ while to stay loyal to their ships.
Standing in the stead of any commander has long been the jumping off point from which a career could be made, or broken. Ambition not withstanding, many men were good at being Lieutenants and stuck with it throughout their careers. Whether aboard a man-of-war or a freebooting schooner, a knowledgeable, loyal and capable First mate was always welcome.