3. The rectangular flag is chiefly used for a flag officer's signal.
4. The shape, consequently, at once denotes whether a flag is that of a club, a flag officer, or a member.
5. The majority of flag officers' signals are coloured: Blue for commodore, red for vice-commodore, and white for rear-commodore.
6. The international code of signals enables yachts to communicate with each other, and is also used for dressing ship.
The ensign should be flown from the peak of the main-sail on a sailing yacht, when under way, and from a stern flag pole when moored.
On a yawl, it should be hoisted at the mizzen truck.
On a steamer, launch, or dinghy, it should be flown from a stern flag pole, when under way or at anchor.
Club Burgee.—The burgee should measure in length about one-half inch for each foot of height of truck from the water; width to be two-thirds of the length. Private signals may be smaller.
The burgee should be flown from the mast-head or truck of a cutter, sloop, or cat-rigged yacht, the main truck of a yawl, the fore truck of a schooner and steamer, and from the bow pole of a launch or dinghy.
Flag officers' and private signals should be flown from the truck of a cutter, sloop, or cat-rigged yacht, the main truck of a schooner, yawl, or steamer, and from the bow pole of a launch or dinghy.