Splice the Mainbrace is an "order"
Splice the mainbrace is an order given aboard naval vessels to issue the crew with a drink. Originally an order for one of the most difficult emergency repair jobs aboard a sailing ship, it became a euphemism for authorized celebratory drinking afterward, and then the name of an order to grant the crew an extra ration of rum or grog.
The phrase is a mainstay of pirate vernacular in popular culture.
Braces are the lines which control the angle of the yards. On the first rate men-o-war, the mainbrace was the largest and heaviest of all the running rigging; the mainbrace on HMS Victory was 5 inches (13 cm) in diameter. Gunners commonly aimed for the braces during naval battles, with the mainbrace being the prime target. If the mainbrace was shot away, it was usually necessary to repair it during the engagement; the ship was unmanoeuvrable without it and would have to stay on the same tack. Even repairing it after the battle was a difficult job; the mainbrace ran through blocks, so it could not be repaired with a short splice or a knot. Splicing in a large run of hemp was strenuous work, and generally the ship's best Able Seamen were chosen to carry out the task under the supervision of the Bosun (Boatswain).
On completion of the task, it was customary for the men to be rewarded with an extra ration of rum.
The Bosun would take a sip from the ration of each of the men he had selected for task. Eventually the order "Splice the mainbrace" came to mean that the crew would receive an extra ration of rum, and was issued on special occasions: after victory in battle, the change of a monarch, a royal birth, a royal wedding or an inspection of the fleet. In cases where the whole fleet was to receive the signal, it would be run up with a lift of flags or signalled by semaphore.
A ration of rum a day was standard issue in the Royal Navy until 1970, when concerns over crew members operating machinery under the influence led to the rum ration being abolished. Restrictions were placed on those who could "Splice the mainbrace": any man or officer over the age of 20 who desired to take it received an extra issue of one-eighth of a pint of rum. Lemonade was issued those who did not wish for the rum. The rum was mixed with water to make grog for all ratings below Petty Officer. Only ratings marked "T" in the ship's books could draw rum, grog or lemonade when the main brace was spliced and no payment in lieu was available. Those under 20 were marked "U.A." (for under age) in the ship's book; they were similarly barred from drawing the daily rum ration. The issue of rum to Wardroom and Gunroom officers was stopped in 1881 and ended for Warrant officers in 1918; splicing the mainbrace was the only time that officers could be issued with rum.
Other navies abolished the grog allowance far earlier (the United States Navy after the American Civil War), but the order persisted, allowing the crew to take another drink in place of rum or grog; in 1845 it is recorded as being substituted for the more rowdy "Crossing the Line" ceremony. Nowadays, the Canadian Navy is more generous with the allowances, allowing crew members to take 87.5 millilitres (3.08 imp fl oz/2.96 US fl oz) of sprits compared with the 62.5 millilitres (2.20 imp fl oz/2.11 US fl oz) allowed by the Royal Navy, although the Royal Navy does make allowance for paucity of supplies, permitting two 350 millilitres (12 imp fl oz/12 US fl oz) cans of beer may be issued if commercial spirits are not available.
Permission to issue the order to splice the mainbrace is heavily restricted - the Royal Navy allows only the Queen or the Admiralty Board to do so; the Canadian Navy permits the Queen, the Governor General of Canada or the Chief of the Defence Staff to issue it. When the Mediterranean fleet received the order from the Prince of Wales (the future Edward VIII) in 1932 it was the first time it had happened since 1918; it was accompanied by the order to "Mend and make clothes", another archaic signal which grants the crew a half-day holiday. Ships in most of the victorious fleets received the order at the end of the Second World War; one ship received the order while still under attack. Nowadays, the order is somewhat more freely given (the Queen issued it after reviewing the fleet off Portsmouth in 2002). documentation_license