The analysis of the movements of celestial bodies and distance- measuring techniques which constitute the basis of navigation science has been known to sailors since ancient times. The 360° Research Group will create a scientific broadcast in which the ancient navigational tools re-manufactured by the Group are utilized during the journey of Uluburun II, thus comparing ancient and modern navigation science.
The science of navigation has been very important and confidential in every period of the history of man. The confidentiality of the navigation science avoided the transfer of the information to current times. It is hardly possible to navigate safely for a captain without the knowledge of open sea and navigational information even if in the Mediterranean Sea . It is seen that the courses and the journey durations signals long-distance journeys when ancient courses are considered.
The instability of weather conditions especially in East Mediterranean and the Aegean Sea increased the necessity of navigation.
The reflective questions relating to this matter that we hope to illuminate;
The navigation of a trade ship sailing port to port could not be based on incidental knowledge of questions concerning course, directions, loads or weather conditions. For this reason the tradition of transferring information and recording was very vital. However the secrecy of the information prevented us to obtain it today. Until recently the captains of galleys and trade ships has saved their maps or logbooks in lead boxes avoiding anyone to reach.
The night navigation was obligatory due to many reasons even if the navigation was mainly shore based. The wind changes and the distance of the course made night navigations very frequent. The need to navigate at night brought the necessity of interpreting sea astronomy. However it is still a wonder how the angles of the celestial bodies were interpreted or a reference was determined. The instruments used for, measuring angles of the celestial bodies are a subject of research. We assume that distance-measuring instruments were invented to explore shores, measure roughly long-distances for a safe journey during day navigation. However these are also separate subjects of research.
• The necessity of sketches and designs emerged with the consideration of these facts. This lead to the invention of the primitive maps. (Conveying information by designs is the oldest tradition of the mankind.)
• The importance of stars for night navigation passes to the sun during day navigations. Considering that compass was not yet discovered, it is probable that an instrument of direction with the reference of east was being used. (The history of man involves many examples of direction and time determination, especially by taking sun as reference.
• The need of continuous time knowledge necessitated a time measuring instrument.
It is our belief that open sea navigation was more important than it has been considered due to the reasons given above contrary to the thesis that regards shore navigation as main type of navigation in ancient times. For shore navigation is very hard and dangerous in terms of maritime. A good sailor prefers a course in open sea to a course that the wind changes fast, the waves are strong and the shallows are abundant. Naturally the contrary conditions are present in open sea.
This research has being carried on under the guidance of PhD Serdar Evren from Ege University, Faculty of Sciences, Department of Astronomy and Space Sciences, Selcuk Nas and Tevfik Aslan, Professors at 9 Eylul University, Faculty of Management and Administration of Maritime.
Some of the ancient navigational tools to be analyzed and used in this projects are:
Kamal is an ancient Arabic navigation tool, which was invented for open sea navigation in 9 th C. The main principles of the tool were based on the knowledge of the Greek scientists and mariners of the late-period Roman Empire . Arabic mariners used Kamal to measure the height of the celestial bodies at Red Sea and Indian Ocean for 6 centuries.
The simplest form of Kamal was composed of a string knotted and attached to a rectangular wooden plate. The observer was using the string while he held the ruler on the other hand at the distance from the eye, and line up the top with the body and note where the horizon crosses the scale. Any one measurement of this kind is not likely to be accurate to the precision it can be read. The lenght of the string or the knots on the string would give the average vertical angle in terms of an Arabic unit named isbâ which equals to 360°/224 = 1° 37´. The angle would increase or decrease according to the number of the knots on the string.
It was a very practical system during that period. The observer could count the knots even in the darkness. The observation was mainly made when the observer was seated in order not be affected by the swinging of the ship for a sound measurement.
3000 years ago Phoenicians sailed through the coast of the West Mediterranean and the Northwest Atlantic via celestial navigation. There is no doubt that past civilizations prior to Phoenicians had relied on the stars for finding their way at sea. However, there was a necessity to know the constellation of stars and the North Star for sailing via celestial navigation. The civilizations in the antique era had gained this knowledge.
The first voyages in ancient times had been to curtail sea travel due to the lack of knowledge, so this enabled them to sail through the day and anchored at night. The priority during a was not to lose the track of the coastline but to follow it securely until they reached their aimed destination. However, mankind’s knowledge about the sky had started to increase and this ended dependency on path-finding via the mainland. Thus seamen sailed to open seas.
The seamen of the antique era had faced an important question when in the oceans. This was how to find directions in the open seas?
This question had forced the seamen to search for some signs for a possible solution in the nature. Then they had developed some instruments for sea-travel in the same direction. The compass rose was one of the first instruments of this effort.
It was known that the compass roses were initially used by Phoenicians. Thereafter it was used during the antique Greek era and further developed by Italian mariners. The aim of the compass rose was based on path-finding and sailing according to the direction of the wind.
At the time of Homer (B.C. 900), Greek mariners were faced with winds blowing from 4 different directions when navigating. These were respectively: Bores (north), Euros (east), Notos (south) and Zephuros (west). The number of direction of the winds was thereafter increased to 8 due to the ever longer sea-travels. These were called Boreas (north), Kaikias (northeast), Apeliotes (east), Euros (southeast), Notos (south), Lips (southwest), Zephuros (west) and Skiros (northwest).
There were various techniques used when at open seas to determine the direction of the wind blowing To follow the daily movements of the sun was an important step to find the way the wind blew. However, this type of way-finding was not more reliable than result from the observation to follow the polar star at night. Especially at nights, mariners had precisely determined both the direction the wind blew and thus the way they wanted to navigate with the help of the polar star. Further, mariners had estimated the direction of wind was blowing with the help of heat and humidity of that wind. This method was the most reliable one until the discovery of the magnetized compass.
The Italian mariners had developed the Greek’s 8-directed wind system. Therefore, they called the winds respectively: Tramontana (north), Greco (northeast), Levante (east), Sirocco (southeast), Mezzodi (south), Garbino and later Africus or Affricone (southwest), Ponente (west), and Maestro (northwest).
This system was later developed to 12, 16 and 32-directed winds. However, the latter system had lost its significance and usage in the 13 th century when the magnetized compass had become common.
The ancient mariners had made extensive use of observing the polar star and constellations of stars like Ursa Major and Ursa Minor at night to set the time.
Nocturnal is an instrument mainly made up of fixing one of two wooden slabs or two brass dishes onto another. The area covering the big dish was divided into 12 equal pieces which depicted the months. However, the relatively small dish was divided into 24 equal pieces which depicted the daily hours.
There was a handle at the edge of the big dish to grip it and there was a pointer rod aligning itself from the center through the top of the small dish.
In order to set the time via Nocturnal, one should fit the cog depicting the hour at 12.00 located at the small dish onto the cog depicting the day on the big dish. Then, by holding the instrument at an arm’s length from the observer, the polar star was to be observed through hole of fixed dishes. The pointer rod was to be aligned through the indication marks at the Ursa Major and Ursa Minor. Thus, observer could easily read the time looking over the face of the small dish.