MANUAL OF YACHT AND BOAT SAILING AND ARCHITECTURE DIXON KEMP (11th and final edition, 1913)
A. Aboard.-Inside a ship or on the deck of a ship. "Come aboard, sir," is a sailor's way of reporting himself on board after leave of absence. To run or fall aboard a vessel is for one vessel to come into collision with another. A sail is said to fall aboard when, from the lightness of the wind or other causes, it ceases to blow out. To haul the boom aboard is to haul the boom in by the mainsheet from off the lee quarter. About.-Having tacked. "She's about!" she is going to tack or has tacked. "Ready about" is the signal given for the men to prepare to tack the ship. "About ship!" or "'Bout ship !" is the order given to tack, that is to put the vessel on the opposite tack to the one she is on when the order is given to tack. To go about is to tack. Abreast.-Synonymous with "Abeam." Side by side. To Breast.-- To come abreast.
Absence Flag.-A rectangular blue flag hoisted below the starboard crosstree to denote that the owner is not on board the yacht. When the owner steps on board the flag is lowered. This is an American custom which is gradually being adopted in Europe. It is a most useful regulation.