Originally, the beacons of seafaring used wood, brushwood, tar or coal as fuel, later oil, gas or electricity were used to generate the light. Because of their lack of accuracy, radio beacons are rarely used in shipping today.
The roots can be found in the beacons of shipping , which were used to mark port entrances or for orientation. It started with light signals on land (land fire), later also on lightships , which were equipped with open fire ( tar ) or torches . Lighthouses built for this purpose can still be found along the coast .
The Greek poet Aeschylus (525–456 BC) describes in the Oresty (Agamemnon, verses 280–311) the notification of victory in the Trojan War and of the capture of Troy by fire mail over a relay of beacons over hundreds of kilometers to Argos .
The ancient lighthouse of Alexandria was built around 300 BC. Until its collapse in the 14th century AD, it was considered one of the seven wonders of the world . In the Middle Ages , the highest watchtower of port sites was sometimes also used to maintain a beacon. B. the Belfry of Dunkirk . Firebloods and blackout beacons were also used for direction finding into the 17th century . The Carta Marina from 1539 records a number of blooms along the southern Baltic coast.
The view of fire, the visibility of luminous objects, is about twice as wide during the day as that of unlit objects. The lights can improve visibility, especially in cloudy weather. The development of the Fresnel lens brought the decisive breakthrough in the efficiency of the light output and improved the effect of the beacon. What has proven itself in shipping has also been adopted in a similar form in aviation .
Neuwerk (planned as a lighthouse in 1286, tower since 1310, lighthouse 1814–2014, today "private fire")
early beacon and watchtower - the Dunkirk belfry (1233 / 15th century)
Lighting in shipping
Many navigation marks visible during the day emit light in the dark or in poor visibility.
A distinction is made according to their navigational function:
The beacons are designed so that they can be easily distinguished from one another. For this purpose, the flashing sequence (timing) and speed (return) as well as the color of the fire are varied as an identifier .
Further characteristic values are the range and the height of the beacon above mean high water or mean water level ( chart zero ). The different construction methods and paints help the navigator to distinguish the beacons during the day.
Scope and visibility
The range is the distance at which a beacon can still be perceived when visibility is good. It depends on the light intensity of the beacon and isgivenin nautical miles for a certain degree of visibility of the air .
Visibility is the distance at which a beacon is justvisibleon the horizon (chimney) from a certain eye level, i.e. H. as soon as itappearsover the horizon for the first time on approach. So it depends on the height of the beacon and the observer above sea level and is due to the curvature of the earth . The range of a beacon is usually greater than its range of vision. Therefore, when the view is clear, the reflection of the beacon in the dark sky or the clouds can often be perceived outside of the range of vision, i.e. before it appears in the rear sight.
|F.||fixed||F.||Celebratory fire||Steady light|
|Oc||occulting||Ubr.||Broken fire||The phases of light are longer than those of the blackouts|
|Iso||isophase||Valid||Common mode fire||The phases of light and dark are equally long|
|LFl||long flash||Blk.||Blink||The phases of the light are shorter than those of the blackouts. A blink is at least two seconds long|
|Fl||flash||Blz.||lightning||The phases of the light are shorter than those of the blackouts. A flash is less than two seconds long.|
|Q||quick||Fkl.||Twinkle light||Light appearing in rapid succession (50-60 times per minute)|
|VQ||very quick||SFkl.||Fast twinkle light||Light appearing in rapid succession (100–120 times per minute)|
|UQ||Ultra quick||UFkl.||Ultra-fast sparkling light||Very rapid light appearing one after the other (200–240 times per minute)|
|Mon||Morse code||Mon||Morse code||Light phases correspond to a letter of the Morse code|
|IQ||Interrupted Quick||Fkl.unt.||Interrupted sparkling fire||Flashes of sparkling fire interrupted by blackout|
|Y||yellow||g., or.||Yellow, orange||Yellow or orange light|
|M.||miles||sm||Nautical miles||Indication of the range of the fire|
|Fl (3) 12s||Blz. (3) 12s||The group consists of 3 flashes, the recurrence is 12 seconds|
|Fl (3) 12s 18M||Blz. (3) 12s 18sm||As before, but with a fire range of 18 nautical miles|
- Adolf Miethe : civil engineering, coastal lighting, aerial photography (= technology in the twentieth century; Volume 5). Westermann, Braunschweig 1920, pwr.wroc.pl