Schwimmtor
Encyclopedia
The Schwimmtor also known as the Sperrschiff (Blocking ship), was a floating barrier designed to protect the areas along the Donaukanal
in Vienna
from flooding and ice. It was built by Wilhelm von Engerth, entered service on 13 December 1873, and was scrapped following World War II
.
A rounded indentation was carved into the left-hand (Brigittenau
) quay wall, where the Schwimmtor was to be stowed when it was not needed. Just downstream of this indentation, the quay wall jutted out into the middle of the canal, thereby forming a support against which the barrier could be placed when it was needed.
Supporting the barrier with the same sort of elongated wall on the right-hand (Nußdorf
) bank, thus creating a sluice-like gate, would not have been possible, because the current would have made it impossible to remove the barrier again once it had been placed across the canal. For this reason, a niche was carved into this quay wall. The niche was capped and housed two moveable steel barriers (the Stemmtor and the Anlagetor).
These moveable steel barriers could be brought into position by turning a capstan
located above the niche. This was connected to the barriers by a rack and pinion
, which turned the Stemmtor outward and moved the Anlagetor out of the niche in the wall to form the second support for the floating barrier.
Both the Stemmtor and the Anlagetor were steel truss
constructions designed to absorb pressure placed on the floating barrier and to transfer these to the quay wall, to which the Stemmtor was attached.
In order to open the Schwimmtor, the moveable steel barriers were wound back into the niche in the wall using the capstan. The current in the canal would then naturally push the floating barrier back to the Brigittenau quay.
The Schwimmtor could be made to sit lower in the water if loaded with ballast. However in order to prevent it from blocking the bottom of the canal, four strut
s made of cast iron
and filled with concrete
were produced. These ensured that an opening 95 centimetres tall was kept free. The small size of this opening resulted in a very rapid passage of water with great destructive force. The struts were therefore placed on a concrete plate 126 centimetres thick and 30 metres long.
es and the natural current of the canal. Wilhelm von Engerth had not approved the construction of a steam-powered winch because it would have been too expensive.
The Schwimmtor was produced in the John Cockerill’s steel factory in Seraing
(Belgium
) under the Austrian chief engineer J. Ritter von Kraft. It was assembled in the shipyard
in Linz
(Upper Austria
).
The Schwimmtor was coated with steel sheets on its sides and on the bottom. These were 10-12 millimetres thick and riveted in place.
2000 kilograms of cast iron were kept on board as ballast. Up to 1200 granite stone blocks weighing 17.5 kilograms each could also be loaded as required. The Schwimmtor’s water tanks could also be flooded to make the barrier sit deeper in the water.
The decision to employ the Schwimmtor depended on the level of the water at the Ferdinandsbrücke (today the Schwedenbrücke). When the Danube flooded, ballast was loaded onto the barrier to make it sit deeper in the water, although it was essential that it never completely blocked the flow of the canal. The amount of ballast on board therefore had to be constantly adjusted as the level of the water in the Danube rose and fell.
In order to guard against ice being driven downstream in winter, it was sufficient to place the barrier across the surface of the canal. The Schwimmtor’s straight sides meant that very little ice was pushed beneath it. It was however important that the barrier could rise and fall with the level of water in the canal.
The Schwimmtor was later fitted out with “ice needles”. These were steel spikes that could be attached to the sides of the barrier. They reached to the bottom of the canal and served to catch ice chunks before these could pass underneath the blockade.
and was finally scrapped after World War II
.
The rounded indentation in the quay wall on the Brigittenau bank, the supporting wall jutting out into the canal, and the niche in the wall on the Nußdorf side of the canal have all survived to the modern day. The capstan which was used to move the Stemmtor and Anlagetor has also been preserved.
Donaukanal
The Donaukanal is a former arm of the river Danube, now regulated as a water channel , within the city of Vienna, Austria...
in Vienna
Vienna
Vienna is the capital and largest city of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.723 million , and is by far the largest city in Austria, as well as its cultural, economic, and political centre...
from flooding and ice. It was built by Wilhelm von Engerth, entered service on 13 December 1873, and was scrapped following World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
.
Supports
The Schwimmtor was located 166 metres downstream of the Brigittenauer Spitz. The site was chosen because the canal was thin enough at this point that the floating barrier could withstand the pressure which would be caused by an accumulation of floodwater or ice.A rounded indentation was carved into the left-hand (Brigittenau
Brigittenau
Brigittenau is the 20th District of Vienna . It is located north of the central districts, north of Leopoldstadt on the same island area between the Danube and the Danube Canal...
) quay wall, where the Schwimmtor was to be stowed when it was not needed. Just downstream of this indentation, the quay wall jutted out into the middle of the canal, thereby forming a support against which the barrier could be placed when it was needed.
Supporting the barrier with the same sort of elongated wall on the right-hand (Nußdorf
Nußdorf, Vienna
Nußdorf was a separate municipality until 1892 and is today a suburb of Vienna in the 19th district of Döbling.- Location :Nußdorf lies on both banks of the Nußbach , where the brook meets the Danube Canal...
) bank, thus creating a sluice-like gate, would not have been possible, because the current would have made it impossible to remove the barrier again once it had been placed across the canal. For this reason, a niche was carved into this quay wall. The niche was capped and housed two moveable steel barriers (the Stemmtor and the Anlagetor).
These moveable steel barriers could be brought into position by turning a capstan
Capstan (nautical)
A capstan is a vertical-axled rotating machine developed for use on sailing ships to apply force to ropes, cables, and hawsers. The principle is similar to that of the windlass, which has a horizontal axle.- History :...
located above the niche. This was connected to the barriers by a rack and pinion
Rack and pinion
A rack and pinion is a type of linear actuator that comprises a pair of gears which convert rotational motion into linear motion. A circular gear called "the pinion" engages teeth on a linear "gear" bar called "the rack"; rotational motion applied to the pinion causes the rack to move, thereby...
, which turned the Stemmtor outward and moved the Anlagetor out of the niche in the wall to form the second support for the floating barrier.
Both the Stemmtor and the Anlagetor were steel truss
Truss
In architecture and structural engineering, a truss is a structure comprising one or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes. External forces and reactions to those forces are considered to act only at the nodes and result in...
constructions designed to absorb pressure placed on the floating barrier and to transfer these to the quay wall, to which the Stemmtor was attached.
In order to open the Schwimmtor, the moveable steel barriers were wound back into the niche in the wall using the capstan. The current in the canal would then naturally push the floating barrier back to the Brigittenau quay.
The Schwimmtor could be made to sit lower in the water if loaded with ballast. However in order to prevent it from blocking the bottom of the canal, four strut
Strut
A strut is a structural component designed to resist longitudinal compression. Struts provide outwards-facing support in their lengthwise direction, which can be used to keep two other components separate, performing the opposite function of a tie...
s made of cast iron
Cast iron
Cast iron is derived from pig iron, and while it usually refers to gray iron, it also identifies a large group of ferrous alloys which solidify with a eutectic. The color of a fractured surface can be used to identify an alloy. White cast iron is named after its white surface when fractured, due...
and filled with concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
were produced. These ensured that an opening 95 centimetres tall was kept free. The small size of this opening resulted in a very rapid passage of water with great destructive force. The struts were therefore placed on a concrete plate 126 centimetres thick and 30 metres long.
The Schwimmtor
The Schwimmtor was a symmetrical-shaped barge without any means of propulsion. It could only be brought into place by means of man-powered winchWinch
A winch is a mechanical device that is used to pull in or let out or otherwise adjust the "tension" of a rope or wire rope . In its simplest form it consists of a spool and attached hand crank. In larger forms, winches stand at the heart of machines as diverse as tow trucks, steam shovels and...
es and the natural current of the canal. Wilhelm von Engerth had not approved the construction of a steam-powered winch because it would have been too expensive.
The Schwimmtor was produced in the John Cockerill’s steel factory in Seraing
Seraing
Seraing is a Walloon municipality of Belgium in Province of Liege. The municipality of Seraing includes the old communes of Boncelles, Jemeppe-sur-Meuse, and Ougrée. With Liège, Herstal, Saint-Nicolas, Ans, and Flémalle it forms the greater Liège agglomeration...
(Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
) under the Austrian chief engineer J. Ritter von Kraft. It was assembled in the shipyard
Shipyard
Shipyards and dockyards are places which repair and build ships. These can be yachts, military vessels, cruise liners or other cargo or passenger ships. Dockyards are sometimes more associated with maintenance and basing activities than shipyards, which are sometimes associated more with initial...
in Linz
Linz
Linz is the third-largest city of Austria and capital of the state of Upper Austria . It is located in the north centre of Austria, approximately south of the Czech border, on both sides of the river Danube. The population of the city is , and that of the Greater Linz conurbation is about...
(Upper Austria
Upper Austria
Upper Austria is one of the nine states or Bundesländer of Austria. Its capital is Linz. Upper Austria borders on Germany and the Czech Republic, as well as on the other Austrian states of Lower Austria, Styria, and Salzburg...
).
- Measurements:
-
- Length: 48.6 metres
-
- Width in the middle: 9.5 metres
-
- Width at the tips: 1.0 metres
-
- Height: 5.7 metres
-
- Weight: 440 tonnes
The Schwimmtor was coated with steel sheets on its sides and on the bottom. These were 10-12 millimetres thick and riveted in place.
- Additional features of the Schwimmtor:
-
- Boiler with 30 m² heated surface
-
- Two centrifugal pumps (each of which could shift 165 cubic metres of water per hour)
-
- Two manual pumps
-
- A manual device for loading ballast (which could load 1000 stones per hour or unload 600 stones per hour)
-
- Steam heating, which was designed to prevent the valves and pipes connecting the pumps from freezing.
2000 kilograms of cast iron were kept on board as ballast. Up to 1200 granite stone blocks weighing 17.5 kilograms each could also be loaded as required. The Schwimmtor’s water tanks could also be flooded to make the barrier sit deeper in the water.
The decision to employ the Schwimmtor depended on the level of the water at the Ferdinandsbrücke (today the Schwedenbrücke). When the Danube flooded, ballast was loaded onto the barrier to make it sit deeper in the water, although it was essential that it never completely blocked the flow of the canal. The amount of ballast on board therefore had to be constantly adjusted as the level of the water in the Danube rose and fell.
In order to guard against ice being driven downstream in winter, it was sufficient to place the barrier across the surface of the canal. The Schwimmtor’s straight sides meant that very little ice was pushed beneath it. It was however important that the barrier could rise and fall with the level of water in the canal.
The Schwimmtor was later fitted out with “ice needles”. These were steel spikes that could be attached to the sides of the barrier. They reached to the bottom of the canal and served to catch ice chunks before these could pass underneath the blockade.
The weir and lock in Nußdorf
The Schwimmtor remained in service even after the construction of a weir and lock in Nußdorf, but fell out of use during World War IWorld War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
and was finally scrapped after World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
.
The rounded indentation in the quay wall on the Brigittenau bank, the supporting wall jutting out into the canal, and the niche in the wall on the Nußdorf side of the canal have all survived to the modern day. The capstan which was used to move the Stemmtor and Anlagetor has also been preserved.