Nautical terminology is dangerous, moving water. As soon as you think you understand a word you’ll read something which gives a different interpretation.
A vang, in the British mind, is a line which controls a gaff or a sprit. It is attached to the upper end of the gaff or sprit and can be made fast at one or other quarter. A large vessel may have two vangs, one for each quarter.
But North American people call a kicking strap a vang, and this usage is spreading among other English speakers. It now becomes difficult to define vang in simple terms: it has two meanings.
A gaff is a spar which carries the head (the upper edge) of a 4-sided fore-and-aft sail. Unless, of course, the gaff is vertical, when it becomes a gunter yard and the sail may be 3-sided or 4-sided. And unless the 4-sided sail is a lug-sail, the upper edge of which is supported by a yard not a gaff.
Traditionally a yard supported the upper edge of a square sail (never square, of course; usually rectanguloid!), and was symmetrical on either side of the mast to which it was attached. In use, it was horizontal (square to the mast). A lug-sail yard is almost never symmetrical at the mast and is rarely horizontal.
Incidentally, fishermen use an entirely different gaff to spear and land big fish.
If meanings are turbulent, then spelling is a maelstrom. The debate between balance lug and balanced lug is fierce; blood has been spilled. The debate between Dead Reckoning and Ded(uced) Reckoning has consumed countless kilobytes and illuminated nothing but pixels. I have watched two foredeck hands arguing endlessly about whether to fake the anchor rode or to flake it, while the ship sailed empty-headed into the anchorage.
Through the centuries the overfalls have been illiteracy and babel.
During the Middle Ages, and even into the early 20th Century, spelling was virtually irrelevant. Illiteracy was normal, and even more usual aboard ship: sailors were recruited, not for their three Rs, but for their ability to work hard and obey orders. When asked to “Set the mizzen topgallant staysail” they cared only about handling the correct haulyards, downhauls and sheetlines, while watching out for the boatswain’s starter and the midshipman’s rattan cane. The men who spoke no English learned the words parrot-fashion, following the dialects and accents of those who purported to speak English. Small wonder that haulyard became ha’lyard (and that it’s now often spelled halliard). Easier for the foreigner (or even the pressed Cornish yokel) to say bo’s’n than boatswain (and easy for us now to spell it bosun).
The bane of modern grammarians (and the delight of philologists) is the process of losing the noun described by the adjective: mizzen is a classic (!)
The mizzen mast is the aftermost mast of the ship; it’s often called the mizzen. The mizzen sail is often, simply, the mizzen. The adjective is spoken and the context provides the noun. Similarly, the lines which control the mizzen sheet (or sail) (the mizzen sheet lines) have become mizzen sheets. Indeed, the adjectival sheet to describe a line has become sheet, as a noun, everywhere on the boat.
It’s even become a verb: “Would you sheet in the main, please Fred?”
What follows shines a flickering light on some meanings of some words: the darkness hides shoal waters.
These words are clickable!