German shipping in the 1920s

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Deutsche Schifffahrt in the 1920s is a shortened title that describes the technical development of the German merchant fleet in the 1920s and 1930s. It is a joint contribution of a working group of the German Maritime Museum (DSM) Bremerhaven and the technical committee "History of Shipping" of the Shipbuilding Society (STG). It was created as part of the DSM research focus "German shipping in the 1920s and 1930s in the field of tension between continuities, crises and innovation - visualization of historical processes" and is aimed at the public via the Internet . The database DBSchiff, created in 2006, serves to document the technical developments of this time with regard to today's ship technology . In the meantime, 18 contributions by nine authors with rich, historically interesting image material from the DSM archive have been created and uploaded, which are available to the public. The contributions were divided into the five categories “Propulsion”, “Equipment”, “Shipbuilding”, “Ship descriptions” and “First - bigger - faster”.

The Buckau was the first Flettner rotor ship in 1924.
The Potsdam 1935 at the Blohm and Voss shipyard on the building slipway
AG-Weser, launch of the steamer Bremen , view of the bow shape, the underwater portion of which has been clearly rounded
Blohm and Voss, launch of the steamer Europa . The underwater portion of the bow shape is much more rounded than that of Bremen.
The 70 pfennig stamp from the industry and technology definitive series shows the bulge that is common today
Push convoy with container cargo on the Elbe

German Maritime Museum Bremerhaven DSM

The German Maritime Museum in Bremerhaven was planned and built from 1969 to 1972. It is the national maritime museum in Germany and, as one of eight research museums, combines both exhibition and research activities. The museum was listed as a historical monument in 2005 and is part of the Leibniz Association.

Technical Committee History of the STG

The Shipbuilding Society e. V. (STG) was founded in Berlin in 1899, is a registered association and deals with technical and scientific questions on the subject of ship and marine technology . In the course of time, a growing division of labor developed at the shipyards; many ship machines , auxiliary systems, ship accessories and services were manufactured by the shipbuilding supply industry or provided by engineering offices. The resulting growing need for technical and scientific exchange was promoted by the STG, initially only through annual lecture events, then through the introduction of additional speaking evenings and later the speaking evenings were replaced by speaking days on current technical issues. Technical committees were founded, including in 1935 the technical committee “History of Shipbuilding”.

background

After the transition from steam to diesel motor ships , which international pioneers implemented in inland shipping as early as 1904 , overseas ships followed from 1907/8. The First World War caused a surge in innovation in the propulsion technologies of warships , particularly in the case of submarines . However, it was not until the beginning of the 1920s that diesel engines could slowly establish themselves over steam engines in merchant shipping . Since ships "live" an average of 25–35 years, there were still a few steam engine-powered ships in service in the 1960s.

Technical developments in German shipbuilding at that time

In the 1920s and 1930s, various technical innovations were developed in German shipbuilding and put into practice.

The diesel engine patented by Rudolf Diesel ran satisfactorily for the first time in 1897, was measured by neutral experts and achieved sensational consumption values. The exploitation of his patents resulted in a large number of engine variants, especially in the case of the large, powerful two-stroke engines, whose open design initially resembled steam engines . To increase performance, double-acting diesel engines were developed in cooperation between B&V and MAN and built in 1912/13. They were only ready for use after the First World War. An evolutionary process began which, after almost 100 years, led to very identical engines in the large, slow-running two-stroke engines that drive the propeller directly . The largest of these gigantic engines have 10 to 14 cylinders, a nominal speed of 60 to 80 / min and drive fast, large container ships with more than 75 MW .

The new competition from diesel engines led to further developments in boiler systems, steam engines and steam turbines with the aim of increasing the overall efficiency of the drive system.

There have also been significant advances in navigation and communication.

The auxiliary machines underwent major changes, mainly due to the abandonment of steam. The steering gear was switched from steam to electric operation and later operated electro-hydraulically. Fans and pumps were given electric motors instead of steam engines to drive them, with the advantage that instead of steam lines only direct current cables were laid.

In shipbuilding, after the First World War, merchant shipbuilding also switched from riveting to welding. In the meantime, valuable experience had been gained in warship building, especially in Germany. Significant weight savings are achieved due to the overlapping that is superfluous during welding.

The ship shapes are hydrodynamically optimized, which reduces the flow resistance and the ships require less propulsion power or achieve a higher speed with the same power.

Today's meanings of the technical developments of this time

Drives

The question of steam or diesel was answered at the time by the higher efficiency of the diesel engine (30–35%) compared to the steam engine (15–20%) via the operating costs. The steam turbines were also replaced on most merchant ships from the 1950s due to the higher efficiency of the diesel engine. Only tankers, LNG gas tankers , large, fast container ships and large passenger ships with high propeller power remained the domain of steam turbines (and for a short time also gas turbines ). From the year 2000, the increased performance of the diesel engines replaced the turbine drives here too. The gas tankers, which were previously often operated with steam, are currently being fitted with newly developed so-called " dual-fuel diesel engines ".

For the LNG gas tankers, the diesel-electric drive was also chosen in the transition period, which has meanwhile become the standard for the large passenger ships (today mainly cruise ships ).

The Scharnhorst passenger ship was the first ship in the German merchant fleet to use a turbo-electric drive and to gain experience with it. The disadvantage, lower overall efficiency, was outweighed by advantages such as running smoothness, extensive electrical on-board network due to the passenger facilities (saving on auxiliary diesel generators) and higher redundancy in the drive. These are also the advantages that still apply to the construction of cruise ships today, despite the considerably higher performance.

Another important point, the construction of sister ships (Scharnhorst - Gneisenau), which were equipped with different propulsion systems in the same area, is no longer realized today. The Gneisenau received a geared turbine drive in order to obtain comparative statements about the fuel consumption. Also important were the reactions of the passengers, to what extent the different drives (noise, vibrations) affect the comfort of the passengers.

Particularly when it comes to propelling merchant ships, new studies are currently being carried out in order to relieve the environment and save running costs. The background is on the one hand the extremely increased fuel costs (1 t heavy fuel oil costs around $ 60 / t in 1999 and around $ 600 / t in 2013), and on the other hand the new regulations issued by the IMO to protect the environment. The first results of this work result from dealing with the past. The E-Ship 1, launched on August 2, 2008 at Lindenau (shipyard) in Kiel and later completed by the Cassens shipyard in Emden, was equipped with four Flettner rotors. The shipowner is gaining experience with this "old" technology, which is used as an additional drive.

Shipbuilding, optimized ship shapes

The North German Lloyd (NDL) had the contract for the construction of Bremen at Blohm and Voss and Europe at AG Weser granted to the leading pre-World War II position in the North Atlantic service to get back. They were awarded under the same specifications and boundary conditions, and the shape of the ship shows the respective handwriting of the two shipyards on the Weser and Elbe. They were both examined beforehand in the shipbuilding research institute HSVA and their shape already suggests the bulge in the bow that is common today . The Bremen was awarded the Blue Ribbon on her maiden voyage in July 1929 .

Due to the fire on the Europa, it was finished considerably later. The successful hydrodynamic ship lines and the optimized bow shape made it possible for her sister ship Bremen to be awarded the Blue Ribbon on the test voyage in March 1930. Here, for the first time in large shipbuilding, the ship shapes improved by the Austrian engineer Fritz F. Maier , which he developed in Sir William Froude's test tank in Scotland. Later he improved the shape of the fore in the test tank of the North German Lloyd in Bremerhaven. They were realized much later by his son Erich Maier in shipbuilding. After the Europa, these shipping lines found their way into the construction of many merchant ships and especially with fish steamers . They were marketed and known under the name Maierform .

Barges

So-called express freight ships with their own loading gear and steam drive regularly drove from the seaport of Hamburg over the Elbe into the inland from 1900 . In contrast to the slow tug trains loaded with bulk goods, they transported more valuable piece goods from exports and imports in both directions. At the end of the 1920s, these ships were equipped with diesel engines, which meant that the coal bunkers were no longer available and the crew could be reduced. Efforts are currently being made to shift truck traffic from the congested roads to the well-developed waterways, also for environmental reasons . Even today, bulk goods such as coal and building materials are mainly transported by inland waterway vessels. For export and import general cargo transported in containers from Hamburg today, the percentage is below 5%, although 2–4 crew members carry around 40 to 200 times the number (Elbe / Rhine ) of containers compared to trucks . However, the ship is significantly slower than the truck, it takes about four to ten times the time. Here inland shipping can relieve the roads and the environment in the future . One of the reasons that the Mittelland Canal , the Middle Weser and the Dortmund-Ems Canal are currently being expanded for the large motor freight ship. After this work has been completed, these ships can operate continuously from Bremen to Berlin or the Rhine.

Documentation of technical developments of this time

The contributions were divided into 5 categories

Drives

equipment

shipbuilding

Ship descriptions

Barges

Seagoing vessels

First-Bigger-Faster

See also

Web links