Sail Ship Yards
Spar is a general term for a round piece of timber, very long in proportion to its diameter, used for masts, yards, booms, gaffs, bowsprits, and so on.
A yardarm (often shortened to just yard) is a horizontal spar on a mast from which square sails are rigged. The yardarm is normally constructed of wood or metal. Numerous bits of standing and running rigging are attached to the yardarm to allow the crew to work aloft and to control the sails.
Sails are bent on to the yards, the horizontal timbers slung across the vertical masts. The yard arm could carry a maximum of 30 men so the size of the largest sail (the Main Course) was limited to the weight that could be lifted by 30 men working together on the main yard. Once the size of the main course was set, the sizes of the other sails followed, graded according to the mast and height above deck.
To allow the direction of the vessel relative to the wind to be changed the yard can rotate around the mast. When running directly downwind the yards are 'squared', pointing perpendicular to the ship's centre line. As the ship wants to sail closer to the wind the yards are braced around using the braces. When further rotation is obstructed by other bits of rigging (typically the shrouds), the yard is said to be braced hard round. This angle (normally about 45 degrees) limits how close to the wind a square rigged ship can sail.
The yards represent a considerable weight high above the vessel's centre of gravity. To increase stability, especially in heavy weather, some means is normally provided to lower the yards when they are not being used to set sails. In Nineteenth century warships (where a large crew was available) this was generally by physically taking the upper yards down from the masts and storing them on deck. Merchant ships in the age of sail would also do this before sailing in the Southern Ocean. On modern tall ships the yards are not designed to be brought down on deck, but 'lifting yards' that can be raised and lowered along a short section of mast are often used.
The yardarm allows square sails to be set to drive the ship. The top edge of the sail is 'bent on' (attached) to the yard semi-permanently. Clewlines (attached to the clews - the bottom corner of the sail) and buntlines (attached to the bunt - bottom edge - of the sail) run up the yard and from there to the mast and down to deck. These allow the bottom of the sail to be hoisted up to the yard, so the sail is effectively folded in two. In this state the sail is said to be "in its gear", that is ready for setting or stowing. To set the sail the clewlines and buntlines are let go, and the sheets (attached to the bottom corner of the sail and leading straight down to deck) are adjusted to shape the sail to best catch the wind. For lifting yards the yard must be hauled up to the top of its travel to set the sail.
To stow (hand) the sail the sheets are released and the clewlines and buntlines are pulled tight. The sail folds in half and no longer catches the wind. The crew must then go out along the yardarm in order to bundle the sail up tightly and tie it down with gaskets. To do this the crew stand in footropes suspended beneath the yardarm and balance themselves between that and the yard itself. The person working at the end of the yard has a separate footrope known as the flemish horse. On modern ships a steel wire jackstay runs along the length of the yard, onto which the crew clip their safety harnesses. During the age of sail no such provision was made, and falling from the yard was a real risk.
It is difficult to say what changes in the proportions of masts and yards took place in English ships between the early 17th and the 19th centuries. The difficulty arises largely not only from insufficient knowledge of the earlier period, but from the fact that a scale was fixed only after trials, and by degrees. The topmasts are ever half so long as the masts into which they belong; but there is no absolute proportion in these, and the like things, for if a man will have his mast short, he may the bolder make his topmast long.
It can be taken as an axiom at once that the main-yard will be somewhere about twice the beam of the ship. Long yards give the best results, low down. Higher up, it is different. For easing the ship, it is well to shelve in considerably. The main royal yard can be taken as being just about as long as the beam.
In some respects the change was certainly slight. In the early 17th century, in England at least, the length of the mainmast was fixed by taking four-fifths of the breadth of the ship and multiplying by three. Two centuries later the method was to take the length of the lower deck and the extreme breadth, add them together, and divide by two. If we take a 74-gun ship of about the year 1820, which was 176 ft. long on the lower deck and 48 ft. 8 in. wide, she would have, by the system then used, a mainmast of 112 ft. Manwayrings system would have given her one of 117 ft.
In the proportions of the masts to one another there was a change. In the 17th century the foremast was four-fifths of the main, and the bowsprit was of the same length as the foremast. In the 19th the foremast was eightninths of the mainmast, while the bowsprit was seven-elevenths of the mainmast in the largest ships, and three-fifths in the others. When we come to the relative proportions of masts and yards the difficulty increases, for the standard was not the same.
The seamen of the 17th century calculated the length of the mainyard not by the size of the mast but by the length of the keel. The mainyard, which was the standard for the others, ought according to the best and most absolute estimate to be five-sixths of the length of the keel. But the proportion is not absolute. If it was followed, the yards of a 17th-century ship must have been rather longer than in a vessel of a hundred and fifty and two hundred years later, when the mainyard was eight-ninths of the mainmast, and, a regular scale was fixed throughout. Even so, the proportion was not absolute. Changes were constant. The development of the famous American clippers made a considerable one. So has the growth of the vast four- and five-masted iron sailing ships of the late 19th century. Individual captains have fitted ships according to ideas of their own.
When coming into port, especially during the Tall Ships' Races many modern square riggers will 'man the yards'. All the crew not required on deck to handle the ship will go aloft and spread out along the yards. The Mexican Navy's training ship Cuauhtémoc is famous for manning its yards with its crew standing ontop of the yards, rather than in footropes.
|Join the GlobalSecurity.org mailing list|