Why triangular sails

Learn more. Why triangular sails make a boat to sail upwind? Ask Question. Asked 1 year, 8 months ago. Active 1 year, 8 months ago. Viewed times. What is so special about the triangular shape that helps when sailing upwind?

Improve this question. Add a comment. Active Oldest Votes. Improve this answer. Mike Dunlavey Mike Dunlavey Sign up or log in Sign up using Google. Sign up using Facebook. In order to sail on these seas, sailors had to constantly battle winds that blew against them. In this sort of setting the lateen sail was at its best. Secondly, the earliest evidence of the existence of lateens on the Mediterranean is in Greek Byzantine manuscripts of the late ninth century which show drawings of lateens.

Before this, in antiquity, only the square sail was found in this sea. This would lead us to suspect that the lateen came to the Mediterranean in the wake of the Arab expansion.

Bibliotheque Nationale, MS, grec. They were quite unstable, and were never used to attempt to make headway against an adverse wind and thus were unable to make long journeys to cross oceans. Then suddenly in the s, lateen sails burst on the scene, and ships developed into three masters with square sails complimented by lateen mizzens.

These ships were capable of making long ocean voyages and were used by Columbus, Diaz and Vasco da Gama. Lastly, it seems that during the Byzantine era, the forepart of the lateen sail was changed to a point, making it a complete triangle. The lateen eventually reached North European waters at the end of the Middle Ages, and there developed into every sort of fore-and aft rig.

Likewise, the lateen sail seems to have made its way from the Indian Ocean towards the seas of far south Asia. Since there are drawings from India, which demonstrate the use of the square sail there, and since the Chinese rigged their junks with square sails, it is safe to assume that the lateen sail was an Arab invention that most likely developed on the Red Sea.

The square sail was employed almost universally in the ancient world. It was only during the early Byzantine period in the eastern Mediterranean that any evidence emerges that triangular sails began to appear on the Mediterranean Sea. The square sail, though stable on heavy seas, is not very versatile to make much use of any headwinds. Square sails were still used until very recently on the sewn sambugs of Aden as well as lateen sails.

Many efforts must have been made to make the square sail better for sailing close to the wind, so it could utilize a head-wind. The simplest way was to set a square sail fore and aft, tilting it downwards at the fore end to make a balance lug illustrated here. From the lugsail it was an east step to shorten the luff fore part and heighten the sail aft to lengthen the leech, in order to catch more wind.

The Arab lateen or more correctly, the settee sail is a very effective fore-and-aft rig. It was developed in Arab waters well before the coming of Islam, and may have been the type of sailing ship that the Nabataeans would have used to sail on the difficult waters of the Red Sea.

The final step was taken on the Mediterranean before AD, turning the Arab sail into a triangular sail. This type of sail was used on the Mediterranean for small boats for many years. The methods of sailing an ancient dhow must have been much like those today, since the rig was much the same. In sailing with the wind the Arab lateen functions exactly as a square sail. When steering a course into the wind, the dhow would prefer to ear around, that is, to change tacks by going round stern to wind.

Tacking involves bringing the bow around into the wind, and since Arab vessels were built with small rudders it was difficult or impossible to bring the bow across the wind, if the wind was strong. Wearing around means losing way, but it is easier, to wear is to take the line of less resistance. When wearing, as when tacking, the yard must be transferred to the other side of the mast; but when wearing the wind aids this maneuver, whereas when tacking the wind tends to hinder it.

There was no reefing of sails in a strong wind, but the yard could be lowered, as today, and it is probably that a spare yard and sail of smaller size were carried, as in the vessels seen by Colomb in the nineteenth Century. I demonstrate how the Nabataean people took to sailing ships. The speed at which they did this might be considered remarkable, if it were not for the fact that navigating in a featureless desert is very similar to navigating on a featureless ocean.

Therefore, before the Arabs became seamen they were knowledgeable in navigation skills. In the section below, I will demonstrate the basics of this navigation, whether it be used on the high seas, or in the depth of the Arabian desert.

However, not all Arab tribes knew how to navigate by the stars. Indeed, only a very few had this skill, as even today only the Slayb tribe are known as the trackers and guides in the desert.

See: Where are the Nabataeans Today? Many early sailors sailed along the coast, always keeping land in site. In this way, they simply harbor-hoped along the coast. One wonders what sea captain would have committed himself to the emptiness of the open sea without a knowledge of navigation by the stars. It would seem a small step however, for desert traveling Nabataean merchants to move on to being ocean traveling merchants, if they had the occasion to own ships and the need to transport goods by them.

Modern navigation includes three aspects. Finding latitude, longitude and accurate time-keeping. To obtain their latitude, Arabs measured the altitude above the horizon to a known star, and then deduced from this the altitude of the Pole Star, since the Pole Star was the one star that did not move in the sky. In some cases ancient navigators measured directly the altitude of the Pole Star. This was the simplest method, and was known as the science of qiyas. The easiest method was to use the width of a finger.

Thus land distances were often measured in zams. A more accurate, but still simple instrument was known as a kamal. This was a small parallelogram of horn or wood measuring about one by two inches with a string inserted in the center. On the string were nine knots at measured intervals. The end of the string was held in the teeth. The lower edge of the horn was placed on the horizon while the horn was moved along the string until the upper edge touched the required star. The altitude of the Pole Star could then be deduced from the rahmani.

An alternative way of using a kamal was to move the knots through the teeth until the piece of horn or wood covered the required star altitude. Sometimes Arab and Indian seamen added extra knots marking the latitudes of particular ports of call, or they simply used a kamal on which all the knots indicated particular ports of call. The astrolabe was developed at a slightly later period.

It was a chart was based on the rising and setting of fifteen fixed stars. This sailor will need to replace sails every 2. The total cost of a sailboat mast replacement raises exponentially as you go up in boat size. Proper tension will leave the leeward upper shrouds taut with 15 degrees of heel and a full crew on the rail. The uppers should be tighter than the lowers; they have more load and also stretch more because they are longer. Check the rig periodically, particularly after sailing in heavy air.

Typically, for proper tension, the shrouds should be tightened using these guidelines; uppers are the tightest, and then fwd. Back to the original question about tightness of stays.