Uckermark (ship, 1930)
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The Uckermark was a freighter built by Blohm & Voss in 1930 for HAPAG , belonged to the Neumark class and was the first ship to receive a Benson boiler in 1930 and a high-pressure boiler in 1937, as the Benson boiler was also called after further development by Blohm & Voss.
The ship, which was primarily used for the Dutch East Indies, sought refuge in Somalia when the war began. To avoid the British occupation of the Italian colony, the Uckermark tried to break through to Europe in February 1941. However, shortly after leaving Kismayo, she was caught by a British cruiser. However, the British boarding command could not prevent the initiated self-sinking of the ship.
construction
The ship was built by Blohm & Voss , the launch and the christening were celebrated on May 8, 1930 and on September 20 the maiden voyage from Hamburg to Canada took place. The ship was measured with 7021 GRT, had a deadweight capacity of 9920 tdw and ran at 6000 PSe 14.5 knots. The Uckermark was originally to be called Taunus ; she belonged to the Neumark class of the Hamburg-America Line for service to the Dutch East Indies . This class also included the Neumark from the Howaldtswerke in Kiel , the Kurmark , which was started as Harz and also arose at Blohm & Voss, and the Nordmark (Bauwerft Flensburger Schiffbau-Gesellschaft , started as Eifel ), as well as those for service to Australia planned Staßfurt (shipyard Bremer Vulkan ) and Bitterfeld (shipyard Krupp Germania shipyard ). All six freighters were propelled by an expanded set of turbines from the four Albert Ballin class ships that had received new propulsion systems in the winter of 1929/30. The other two turbine sets were installed in the combination ships Tacoma (8268 BRT) and Vancouver , which were delivered by the Deutsche Werft in Hamburg-Finkenwerder for service to the North American west coast.
Benson boiler from Siemens-Schuckert
The Siemens Schuckertwerk (SSW) had after its inventor Mark Benson named Benson boiler, which as a once-through boiler worked, developed and tested. A prototype was in the Siemens-Schuckertwerk in 1928 and was operated with coal dust as fuel. It had a steam output of 20 t / h and the steam was used for heating purposes and to drive a 180 bar steam turbine that drove a generator. In order to introduce this type of boiler into shipping, SSW signed a license agreement in 1930 with the Blohm & Voss shipyard in Hamburg.
The first boiler for shipping was earmarked for testing after negotiations with HAPAG for the freighter Uckermark . The Uckermark and the Kurmark (7000 GRT) were currently being built by Blohm & Voss for HAPAG, so they had a comparable ship. Both ships had a propulsion power of 6,000 hp, were intended for the East Asian service and each received a total of four cylinder boilers . Two double-ended and two single-ended boilers for an operating pressure of 15 bar, the steam of which drove a four-stage steam turbine system.
Boiler testing
The boiler was installed in July 1930, the first test drive took place on September 10, and the acceptance drive on September 16, 1930. The first trip to Montreal (Canada) was then carried out in order to obtain the first operational results soon.
On the maiden voyage, there were several pipe ruptures due to the salinisation of the steam, which caused deposits on the pipe walls. The deposits led to a deterioration in the pipe wall cooling and therefore to pipe ruptures at the high temperatures. For this reason, the transition point from water to steam, which was previously around 1500 ° C in the combustion chamber, was moved to an area with 700 ° C flue gas temperature. The deposits were a fundamental problem with the Benson boiler; they were solved by flushing the boiler in the port with preheated feed water. This dissolved and rinsed the deposits.
Results
The comparison of the two ships resulted in an average consumption of the Uckermark of 0.256 kg fuel per PSh compared to the Kurmark of 0.303 kg of fuel per PSh for the main drive alone on the first three voyages evaluated .
Reconstruction of the Uckermark
One of the double-ended boilers at the Uckermark was replaced by a Benson boiler for a pressure of 225 bar and a steam mass flow of 20 t / h. It was 5.3 meters long, 4.5 meters wide and 7 meters high and weighed around 100 t. There were four oil burners with a nominal mass flow of 180–200 kg / h on each of the two ends. The two radiant heating surfaces with a total of 125 m² heating surface were located in the burner room , the superheater (74 m² heating surface) and the preheater II were arranged in the next pass and the preheater I and the air preheater (Luvo) were located in the last pass. The preheaters had a total heating surface of 316 m². The piston feed pump with three double plungers was designed for a nominal pressure of 250 bar and the volume flow could be set by switching off the six pistons individually, and the speed could be adjusted in the range of 95–115 / min.
The water in the Benson boiler was expanded to 90 bar at the critical pressure of 225 bar and 410 ° C in the pressure-maintaining valve, evaporated with a temperature drop to 310 ° C, and then the steam was superheated to 460 ° C in the superheater. Due to the flow losses, the pressure at the exit of the superheater was around 70 bar. By the time it entered the nozzles of the upstream high-pressure turbine, the steam pressure was reduced to 60 bar, the temperature here was 440 ° C. In this upstream turbine with a nominal speed of 6000 / min, the pressure was released in two stages to 15 bar and then the steam expanded in the four-stage turbine system.
A step is provided in the high-pressure turbine for reversing, and from here the steam flows through the two reverse turbines of the original steam turbine.
History of the ship
May 8, 1930: Launched and christened
September 20: Maiden voyage from Hamburg to Canada, then shipping area from Europe to the Dutch East Indies
1937: Replacement of the old one by two Benson high-pressure vessels at Blohm & Voss
August 31, 1939: Call to Mogadishu (Somalia) because of the threat of war
September 30th: Launched in Kismayo (Somalia)
February 11, 1941: Due to the threat of British occupation of Italian Somaliland, departure for France
February 12, 1941: The British cruiser HMS Hawkins stopped the Uckermark , the German crew initiated the scuttling
February 14, 1941: The Uckermark is sinking
literature
- Hermann Frahm: The use of high pressure boilers in ship operation with special consideration of the Benson boiler , yearbook of the shipbuilding society 1932
Web links
- Ship description
- Downfall of the Uckermark
- Sea War, February 10–25, 1941, Indian Ocean / East Africa