Many things in this world are recognized as being of a particular national or cultural origin by the way they look. A teepee will immediately be identified as a Native American dwelling, and everybody knows pagodas are unique to particular parts of East Asia.
The same is true of ships at sea. Certain characteristics identify them as having been designed and built in a particular country or region. An obvious example is the junk, peculiar to Asian nations, especially China and Japan. These high-pooped wooden vessels, perhaps with eyes painted on their bows and with sails made of split bamboo, are unique vessels of the region.
In the days of sail, ships seen at a distance were most quickly identified by observing with sails and rigging. Some nations favored proportionally longer yardarms, and therefore their ships had a wider spread of canvas, even without studdingsails. Ships of Middle Eastern origin likely were fitted with triangular lateen sails, suspended from long, drooping yards rigged fore and aft on one, two, or three masts. Other nations favored installing (“steeving”) bowsprits more steeply than others. But one of the readiest identifiers was the shape and size of a ship’s head sails, those fore and aft sails rigged between the bowsprit and the foremast, and so it came to be that one was known “by the cut of his jib.”