The prestige ships of the British Navy were the three-deckers, carefully and lavishly built by the Royal Dockyards and requiring many years of work. Rarely commissioned in peace-time, and preserved with expensive overhauls and rebuilding, the few First Rates served as flagships, and they were the strongest units of the line of battle, even if they were very difficult to handle. Each 100-gun ship had an established complement of 850 men in addition to extras assigned when used as flagships.