Alte Weser (lighthouse)

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Alte Weser Lighthouse
Fig. 1 "Alte Weser" lighthouse - 1992 Fig. 2 Radar-chain, River Weser
Data
function:	orientation-& athwart fire for "Neue Weser"-waterway; routing fire for "Alte Weser"-waterway; antenna carrier of radar-chain Outer-Weser;
optics:	Double-beltoptics with 400mm focal distance; 2000 W xenon-lamp, intensity 424.000 cd;
planing & construction supervision:	Wasser- und Schifffahrtsamt Bremerhaven
built:	1961 - 1964
gone into service:	1st September 1964
height:	NN -22,00 m bis NN + 39,35 m (incl. radar antenna)
foundation:	at NN -22 m, Brunnen-body diameter 15 m, height 11m, above cylindrical shaft diameter 6.5 m (Fig.4)
blaze height	33 m (above German reference surface (NN))
geogr. position:	latitude: 53° 51,80'N, longitude: 08° 07,65'E (WGS 84); 34 42 674 59 70 610 (GK); river Weser-km 114.87;
identification:	F.w.r.gn.
visibility:	white 23.0 sm / red 19.2 sm / green 18.0 sm
audio-signal:	Horn Mo(AL)1min
International indenture number:	B 1188
other equipment:	radar system, beam radio antenna, range of sight-measuring instrument, local control system, water gauge, sea level remote transmission, wind-measuring system, emergency power system, 2 cranes, driving rack, accommodation for several persons
else:	replaced the lighthouse Roter Sand (lighthouse)

The Alte Weser Lighthouse is located offshore from the estuary mouth of the river Weser in the German Bight, southern North Sea (Fig.1). It was built on sand between 1961 and 1964. The Alte Weser lighthouse took over duties and replaced the historical Roter Sand lighthouse on September 1st 1964. The latter was built from 1883 to 1885. The Alte Weser lighthouse was on a German stamp, 1976.

1 General Aspects
2 Construction of Lighthouse "Alte Weser"
- 2.1 Lighthouse "Tegeler Plate"
3 References (German)
4 Arts
5 External links

[edit] General Aspects

The "Alte Weser" lighthouse was built between 1961 and 1964. It consists of steel-coated ferroconcrete and a steel superstructure. It was built offshore at depth -11m NN (normal null) into sand. Its height is about NN 40m. Depending on the color of the light beam, its visibility is between 18 and 23 sm. The only inhabited place where the Alte Weser or Roter Sand lighthouse can be seen with the naked is the German island of Wangerooge (e.g. from the boardwalk at the restaurant "Cafe Pudding").

Fig. 4 "Alte Weser": original technical drawing, 1961

[edit] Construction of Lighthouse "Alte Weser"

Fig. 5 Tower-shaft with foundation at the dry-dock of Howaldtswerke in Kiel

The “Roter Sand“ lighthouse (German transl. “red sand“) is located in the "Outer-Weser" waterway in the German Bight, southern North Sea. At the end of the 1950s the lighthouse had been badly damaged by corrosion, corrasion, and lixiviation of its concrete. To replace the old lighthouse, the “Alte Weser” was built in the years 1961-1964 not far from the former location. Simultaneously, the conditions for the ships' traffic in the "Outer-Weser" waterway were intended to be improved and the new lighthouse was planned to be established as an offshore part of the radar chain on the Weser between Bremen and the North Sea (Fig. 2).

The novel form of the tower (Fig. 4), i.e. its downward tapering tower-shaft together with its cantilevered upper stories was based on a design by Andreas Carstens (dipl. engineer), Bremerhaven. The conical design of the tower was intended to minimize exposure to waves and drift ice. The German Waterway Administration, the Wasser- und Schifffahrtsamt (WSA) Bremerhaven as the responsible governmental agency, assigned the task of workmanship to a cooperative of companies: Philipp Holzmann, Strabag Bau AG, Hermann Moeller. This cooperative instructed the Howalds-factory in Kiel to carry out the steelworks.

Fig. 6 Tower-shaft on offshore-lift platform (Hubinsel) passing the North-Baltic-Sea canal (Nordostseekanal)

Fig. 7 Surface of concrete and flanking concrete reinforcement.

The steelworks for the tower-shaft, the upper stories and the equipment were carried out in a dry dock of the Howaldts-factory in Kiel (Fig.5). The tower-shaft was towed on a floating offshore-lift platform which had been supplied with a central cut-out for the tower, through the Baltic-North-Sea canal towards its destination site in the Outer-Weser waterway (Fig. 6). At the site it was lowered and subsequently washed into the sand to the intended depth. After feeding in a layer of underwater concrete the shaft was pumped empty and the next layers of ferroconcrete were installed (Fig.7). Frequently, adequate supply of building material was hindered and delayed because relatively small coasters were employed which were quite sensitive to the state of the sea and weather conditions. Timing was especially important in order to ensure joints were constructed correctly. To this end, all building materials needed for the underwater concrete had to arrive in time and without delay. Therefore, an optimal weather period was required.

A further interruption happened due to two accidents. The first was fatal when a sudden leak killed two workers. However, the exact reason for the accident was never fully revealed. The tower-shaft which had been lowered and washed into the sand had to be abandoned. The upper stories were detached and transported on the offshore-lift-platform back to Kiel for later use. One year later the upper stories were reused on a second tower-shaft nearby. The old stump of the tower-shaft remains underground today. The hurricane flood of 1962 which cost many human lives in Hamburg and other places at the German coast had no impact on the construction of the lighthouse. The first accident forced a new start to the works in Kiel causing a delay of one year. The second accident happened because of a malfunction of the gripper at the front legs of the offshore-lift-platform. A second platform had to be used in order to repair and replace the first one. In the third year, after the lift-platform had been repaired, the construction works resumed at the tower-shaft and were subsequently completed.

Fig. 8 Upper stories loaded onto offshore-lift-platform at Kiel.

Fig. 9 Upper stories are lifted onto the tower-shaft from the offshore-lift-platform

Fig. 10 Washing boot (Einspuelstiefel)

Fig. 11 "Alte Weser", original photo, 1964

Next, the offshore-lift-platform could pick up the upper stories which were still stored at Kiel (Fig. 8) to join them with the tower-shaft in the North Sea. Under favorable weather conditions the upper stories were placed on top of the tower without complications (Fig. 9). Now, the completing works such as installation of the optics including the corresponding blinds and the installation of the standby-sets were implemented. The power supply of the lighthouse demanded special attention. A 6 kV cable was run from the “Robbenplate” lighthouse (Fig.2) towards “Alte Weser”, washed-in using a special "wash-in-boot" (“Einspuelstiefel”, Fig.10) and threaded into the tower through a protective cable conduit. In addition, measures had to be taken to adopt the same cable for the planned “Tegeler Plate” lighthouse (Fig.12). The foundation of the building was safeguarded with stone ballast poured down on bush mats against rinsing and water erosion. In 1964 the light of “Alte Weser” lighthouse went into service (Fig. 11 ). In 1972, the four crewmen were displaced when the lighthouse became managed by remote control.

[edit] Lighthouse "Tegeler Plate"

Fig.12 "Tegeler Plate" Lighthouse

As an additional improvement of the waterway conditions as implemented by the procedure as a whole (see above), construction of another lighthouse was essential. This effort simultaneously made it possible to take the light vessel `Bremen`out of service. As a location position for the new lighthouse the Tegeler Plate sand bar was chosen. The tower-shaft as well as the upper stories of the Tegeler Plate lighthouse (Fig. 12) were intended to be entirely built as steel construction. The tower-shaft height of about 46 m as well as the local flat water conditions (i.e. average low tide about 2.50 m above ground level) made it possible to rinse the tower-shaft 18 m deep into sand in one step. To this end, washing the tower-shaft into sand as a first step was considered to be followed by placing the upper stories on top as a second step. In this manner corrections of slight discrepancies of the shaft could be made. After the steelworks had been carried out at Wilhelmhaven, the tower-shaft and the upper stories were brought to the intended position by a salvage ship carrying heavy water pump systems, and were rinsed into the sandy ground. The power cable already installed at the “Alte Weser” lighthouse was integrated. The Tegeler Plate Lighthouse went into service in 1966 – it was unmanned and managed by remote control from the beginning. Only emergency quarters were set up for maintenance workers. The base was secured through stone ballasting.

With these arrangements two important steps for the deepening project of the Outer Weser waterway were accomplished.

[edit] References (German)

Leuchtturm Roter Sand: Bildband. Wirtschaftsverlag N.W. Verlag für neue Wissenschaft.
Luttermann, H.-J. Blüsen, Baken, Feuertürme. Convent.
Scheiblich, R. 1998. Leuchttürme an Deutschlands Küsten, 2. ed. Delius Klasing.
Scheiblich, R., and H.-J. Lutterman. 2003. Sterne unter den Wolken. Convent.
Scheiblich, R., and H. Staack. 2002. Leuchttürme Lexikon. Edition Ellert & Richter.
Seedorf, R., and P. Fäthke. 1989. Gerettet! Leuchtturm Roter Sand.
Schnall, U. 1999. Leuchttürme an deutschen Küsten. 4. ed. Ellert & Richter
Stölting, S. 1985. Leuchtturm Roter Sand. 1885-1985. Worpsweder Vlg.,Lil.
Zemke, F.-K. 2000. Deutsche Leuchttürme einst und jetzt. Koehlers Verlagsges

[edit] Arts

The Alte Weser lighthouse as well as Tegeler Plate, Roter Sand and others were shown in various paintings by Katharina Noack. These artist's views provide the most informative, integrative view of the navigational light complex of the German Bay centered around lighthouse Alte Weser.