In theory the Navy, like the Army, was a volunteer force, but with the Navy's worldwide commitments always increasing and its ship-building programme seemingly perpetual,
The younger sons of the middle class - as opposed to the aristocracy, which preferred the Army since only there could wealth secure an instant commission - entered the Navy as aspiring officers, and often did so from a young age. A boy of 12, for instance, might begin in the capacity of a captain's servant, which only meant that he was in effect a trainee and not an actual servant. After a few years at sea he could become a midshipman, a type of non-commissioned officer immediately below the rank of lieutenant. A few men spent time at the Royal Naval Academy, Portsmouth, but most young officers received their education and training aboard ship under the tutelage of the ship's schoolmaster or chaplain, who guided them in mathematics, navigation and other subjects. Once he reached the age of 20 (and the required six years' service at sea), a midshipman took the lieutenant's examination, the passing of which entitled him to that commissioned rank and enabled him thereafter to work his way up the ladder of promotion. While this could be an extremely slow process, in wartime it was not necessarily so, owing to deaths in combat and, above all, from sickness and disease. One could also achieve promotion through patronage - what contemporaries called 'interest'. Since, in marked contrast to the Army, a commission could not be purchased nor promotion secured by financial means, making the best use of one's personal connections was the next best option.
Britain was chronically short of men, with only 65,000 men available in 1794, gradually rising to 140,000 men in 1815. Losses, of course, had to be replaced, and could result from a combination of factors: combat deaths and injury, disease, desertion and injuries sustained in the ordinary course of what was a hazardous duty even without an enemy in sight. The number of volunteers was never sufficient for the nation's needs because conditions aboard ship were so poor, with considerable periods spent at sea, dreadful food, harsh discipline and low pay.
A solution was found in the practice of impressment, whereby the state maintained the right to seize men for service as the need arose. Even contemporaries regarded this legacy of medieval times as an assault on the liberties of free men - not to mention an inefficient method of raising crews - but as Parliament refused to introduce conscription either in the Army or the Navy, the practice was regularly and shamelessly employed. Men in port towns were the most vulnerable to impressment, for they were the most likely to have served at sea, usually aboard merchant vessels or as discharged sailors from the Navy. Some men were exempt: men of sufficient means, i.e. 'gentlemen', seamen already serving in the Royal Navy, fishermen, tradesmen, apprentices, those under 18 or over 55, and a few other categories of men. Anyone else who appeared reasonably fit could potentially fall prey to a press gang, a party of ruffians assembled by a lieutenant, who proceeded to collar those who looked of some use aboard ship. Not only were men taken on the streets, but merchant ships were often stopped as they returned to home waters and stripped of their best sailors. Men were often offered the chance to 'volunteer' so that they could claim the bounty (this varies throughout the wars from between £1 10s and £10) offered to those who willingly enlisted, and thus it is difficult to determine precisely how many men joined the Navy as genuine volunteers. Such men may have accounted for as little as a quarter of a ship's company.