Shipbuilding takes place in specialized companies, the shipyards . There, the individual parts are cut out from steel or light metal sheet and profiles. In steel shipbuilding, Holland profiles (according to EN 10067: bulge profile / bulb profile) are common, these are rectangular profiles with a cross-section similar to that of a railroad track and with a bulge-shaped flange on one side, i.e. roughly a rounded L-profile. The cutting is done in steel shipbuilding with cutting burners. If necessary, the individual parts are curved if they belong to the outer skin. Then they are welded together to form sections. A section can e.g. B. the bulge of the bow, part of the Vorstevens or part of the bottom. The sections are brought to the dock for final assembly (previously also on the Helgen ). There they are welded together. Since they are usually slightly warped, the special skill consists in deforming them by skillfully applying force in order to bring the two sheet metal edges to be welded together to coincide. Deckhouses, chimneys and similar deck structures are manufactured in parallel in the same way, or they are occasionally also made by suppliers. They are then put on as a whole and welded. The welding seams are - as far as possible - made by automatic machines, which reaches its limits in the strongly curved areas of the fore and aft.
The ship is lowered into the water while still in the shell. If it was not built in the dock, but on the Helgen, this process is called launching . The final expansion will then take place at the equipment quay. While the heavy plate construction is manufactured by the shipyard itself, all other components are purchased from suppliers, because the lowest possible depth of production is also most economical in shipbuilding. After test drives, which among other things serve as proof of the contractually agreed speed, the ship is handed over to the owner . It is not uncommon for the final work on the facility and equipment to be carried out during the test drive for scheduling reasons.
Design and construction precede the manufacture of a ship . The design is accompanied by model tests in a shipbuilding research institute to determine the required engine power, maneuverability and behavior in sea conditions and to correct the design if necessary. CFD software is usually not powerful enough to replace model tests. The complex interactions between ship and water push the CFD calculation models to their limits, so that some basic research has to be carried out. Ship constructions are developed with special shipbuilding CAD software.
Pleasure craft shipyards take a slightly different route. Many methods from automobile construction are used there today in order to optimize production and save costs. The modern yacht building is almost solely dependent on computer design and workmanship in fiberglass . The entire boat is fully assembled before it leaves the shipyard for a test drive. Thanks to series production, not every single specimen has to be tested in the water.
History of shipbuilding
The history of shipbuilding can be broken down into epochs, but basic construction principles can also be distinguished, which in shipbuilding based on traditional experience have often remained largely unchanged over centuries.
A distinction must be made between the dugout canoe , its extension to prahm-like boats and those with a riser, as well as the shell construction that was common up to the 20th century , in which an initially created wooden shell was stabilized by subsequently inserted frames, and the skeleton construction , which has been common since the 15th century , in which initially the keel was laid and frames were put on and then planked. After this brief glimpse into traditional building methods, the following is a breakdown into time periods.
Seafaring before antiquity
The earlier doctrine that the first ships were built by the Egyptians is outdated.
Before archaeologically documented at least 40,000 years ago (according to other evidence much earlier) Homo sapiens immigrated to Australia. Thanks to the lower sea level, the sea routes from Asia to Australia were shorter than today, but at least 100 km of ocean had to be crossed over the Timor Trench . For this purpose, ocean-going ships were necessary (if one excludes an unbelievable coincidence). But the evidence remains indirect, as there is no direct archaeological evidence of ships from this time.
At least 12,000 years ago people settled on the previously uninhabited island of Cyprus . It is unclear what type of watercraft was used for the 50 km journey to Cyprus. What is certain, however, is that household effects and cattle were around 8200 BC. Were brought to the island by farmers from the Levant . Other people got around 7000 BC. BC, also well before the Egyptians, obsidian from the island of Melos .
First known ship types
The Egyptians used ships primarily for trips on the Nile . For this purpose, reed was initially used and later also wood . The first occupations in shipbuilding were accordingly carpenter , sailmaker and rope maker . The art of rope-making was not limited to the rigging , the strength of the ships also required ropes that were stretched between the bow and stern so that these end areas of the ship did not sag.
Shipbuilding was further developed by the Minoans , Phoenicians and Greeks . The first longships that were used for sailing in the Mediterranean and Black Sea made increased demands on seaworthiness and stability . At the same time, thick-bellied merchant ships were developed. Repairs often had to be carried out on the high seas or on remote beaches, making the profession of ship carpenter as a crew member necessary. The typification of ships progressed, ship types such as the Bireme or Trireme were built according to fixed rules and proportions. In the early days of Greek and Phoenician shipbuilding, the ships were still built on the beach, later the shipyard and dry dock (around 200 BC) were developed as a specialist company.
In the 3rd century BC In BC , shipbuilding was most developed in Carthage . The construction of large ships like the Quinqueremen of the Carthaginians required sophisticated logistics and the interaction of the individual trades . During the First Punic War , Carthaginian warships were stranded on the coast of Italy. This was the starting signal for Roman shipbuilding. The Carthaginian ships were used as patterns for Roman ships. Carthaginian shipbuilding was copied and the Corvus added as a Roman invention. Within a short time, the Romans created an efficient shipbuilding industry and built a fleet that could compete with the Carthaginians. After the conquest of Carthage, Roman shipbuilding was technically leading, but the Greeks in Egypt built even larger ships. A particularly important shipyard location of the Roman Empire was Misenum on the Gulf of Naples , which was also a naval base, port, naval school ( armaturarum schola ) and the location of the prima adjutrix , a legion of marines .
In the Middle Ages , there were two separate lines of development in shipbuilding in Europe, in the Mediterranean Sea and in the North Sea and Baltic Sea.
The Mediterranean line continued the Roman tradition, while the north of Europe constructed completely differently. Typical for the north was the boat or ship symmetrical in two axes, the bow and stern were built the same and the clinker planking , which only required weak frames , which were connected to the planks with cords.
The Nydam ship from the 4th century is an example of this tradition; it had no sail yet. The Vikings developed this into their longships, which were suitable for long journeys to Iceland , Greenland and Newfoundland . In addition to the long ships for military purposes, they later built bulky merchant ships.
The Vikings used a single square sail . This was true even for the Hanse Kogge , who was also klinkerbeplankt, but already had a markedly differently shaped tail, where the rowing center at Steven was driven. The shipbuilders of the Mediterranean used crawler planking and their ships carried triangular latin sails on one or two masts.
Towards the end of the Middle Ages, when merchants and pirates penetrated the Mediterranean from the north, traditions began to mix up from 1300 onwards. The Bremen cog from 1380 was already planked on the ground. As a result of the mixture, the discovery ship of the early modern era, the caravel and the successor type of the cog, the Kraweel, emerged .
Up until the 19th century, shipbuilding in Europe primarily took place in shipyards on beaches. Most of the time, the ships were built across the direction of travel on the beach. The keel lay on the so-called stacks ; The word “ launch ” is still reminiscent of this way of building ships . The ships were pushed into the water on wooden slide rails. The longitudinal direction was only rarely used. This type of shipbuilding in beach yards limited the size of the ships.
The first Chinese dry docks were developed by the Chinese admiral Zheng He at the beginning of the 15th century and built in Nanjing . On them the building of the treasure ships , which were large for the time, took place, which were even a little longer than the carracks of the late Middle Ages in Europe. Such a dry dock is still preserved in Nanjing today.
The dry dock was re-used in Europe in Portsmouth in 1495 for the first time since ancient Europe . However, it was several hundred years before the dry dock became generally accepted for shipbuilding in the 19th century. For three millennia, wood was the dominant building material for ships.
At the beginning of industrialization , shipbuilders, especially in Great Britain, began to use more iron to replace the crooked wood that had become scarce . This resulted in the composite construction with keel and frames made of iron profiles and planking made of wood. The underwater hull was shod with copper sheet to protect it against vegetation.
For a long time there were reservations about ships made entirely of iron, possibly because iron, unlike wood, could not float. Possibly a storm, which a ship built entirely of iron survived unscathed, brought about the turning point. This made the construction of riveted iron plates common. In Great Britain, the most powerful shipbuilding country at the time, iron shipbuilding reached its peak in 1883 with 860,000 tons and fell within the next few years to 50,000 tons in 1888 and to just 10,000 tons by 1895. In 1878 the first ships were registered with 4,500 tonnes made of the even more suitable shipbuilding material steel , whose share of use in the production volume in Great Britain rose to 4% by 1880, to 60% by 1885 and to a full 95% by 1895.
The first sea-going “iron steamers” built at a German shipyard and driven by a propeller were the Hereditary Grand Duke Friedrich Franz and Grand Duke Konstantin , who built the Neptun shipyard in Rostock in 1851 for Rostock-St. Petersburg Steamship Company built.
After the end of the First World War and due to the severe restrictions imposed by the terms of the Versailles Treaty, the German Navy forced welding technology, as it allowed lighter ships. This was consistently applied, particularly with the armored ships .
After the Second World War , shipbuilding was initially prohibited in Germany and only permitted again from 1951. Until the shipyard crisis in the 1970s, German shipbuilding temporarily achieved a leading position in the world.
Technical structure of shipbuilding
When designing a ship, the geometric shape of the hull is first developed and documented in a line plan. The line plan contains water lines (horizontal cuts), construction frames (vertical cuts in the transverse direction), cuts (vertical cuts in the longitudinal direction) and sometimes also Senten (oblique cuts). For reasons of symmetry and for better visibility, a frame crack usually only shows one half, the stern on the left and the foredeck on the right. The ship is divided lengthways into 20 sections of equal length, which then form the structural frames. The construction frames are numbered from 0 (eighth lot HL) 1 to 20 (front lot VL) 2 . Further frames are used in the area of large changes in shape, i.e. stern and foredeck. These are usually frames halfway apart with the numbering 18.5 and 19.5. In order to represent the entire ship, also aft of the helm and in front of the VL, further frames are inserted. These are then numbered accordingly (for example −5, −4, 21, 22, ...). The aim of the design is to develop a ship shape that meets the requirements of the shipowner and complies with the various hydrodynamic, structural, and manufacturing requirements. At the end of the process there is a compromise between all parameters for the economic use of the ship.
As a rule, an existing line plan is used as a template and geometrically distorted.
The ship is usually designed in this order:
- Requirements for the ship, for example length, width, draft , speed, loading volume, number of container spaces or the carrying capacity
- Division of the ship into the geometry of the holds, tanks, etc.
- A rough general plan GAP ("General Arrangement Plan") is drawn up.
- Determination or estimation of the important hydrodynamic parameters, such as block coefficient CB, center of gravity, resistance
- Then an attempt is made to design the ship shape around the fixed point based on the requirements.
The ship design is always a compromise between the requirements of the shipowner and what is physically feasible.
1 : The eighth perpendicular is usually located at the point where the construction waterline intersects the rudder stock. The construction waterline corresponds to the horizontal section on the specified draft.
2 : The forward perpendicular is at the point where the bow contour intersects the construction waterline. The length between the front and the eighth perpendicular is also called the length between the perpendiculars. The abbreviation for this is LPP from Length between perpendiculars (usually abbreviated to LBP for smaller ships). As a rule, the hydrodynamic parameters are related to this length.
With empirical methods, for example the Holtrop method, with resistance and propulsion tests on a model scale and partly with CFD calculations, a forecast is made of how much engine power the ship will need to reach the contractually agreed speed. The accuracy that is demanded and achieved is enormous. These investigations on the ship's hull go hand in hand with hydrodynamic investigations on the propeller, which are just as complex . Further hydrodynamic investigations concern the maneuvering and swell behavior and partly also corresponding model tests in ice.
To evaluate the cutting ability of an underwater ship design different are Völligkeitsgrade calculated whose values are always first
- Degree of completeness of the main bulkhead (Midship Coefficient ): The area of the main bulkhead up to the construction waterline (KWL) is calculated in relation to the circumscribed rectangle (width KWL × draft) (previously: degree of completeness alpha)
- Degree of completeness of the waterline area (Waterline Area Coefficient ): It evaluates the ratio of the area of the construction waterline to the length × width of the circumscribing rectangle (previously: degree of completeness beta)
- Degree of completeness of the displacement (block coefficient ): Here the displacement of the ship is divided by the circumscribing cuboid (length × width × draft) (formerly: degree of completeness gamma). The smaller the value, the slimmer the hull. Pleasure craft have a small value, tankers or pontoons tend to have a value of 1.
- Prismatic Coefficient : It describes the ratio of the displacement of the ship to the main frame area times the length (previously: degree of completeness delta)
Longitudinal strength: Globally and in the most coarse approximation, the ship is viewed as a bending beam whose cutting loads result from the different distribution of weight, cargo and buoyancy. Transverse strength: A slice cut out in thought is calculated as a U-shaped arrangement of steel girders with neglected interaction with the remaining ship. See also beam theory .
More detailed calculations with FEM software take into account that the ship, as a heavy plate construction, is a complex structure of two-dimensional structures.
In order to avoid recurring calculations, the ribs, frames, beams, hatch coamings and the like are dimensioned in accordance with the building regulations of classification societies .
Today, diesel engines are mostly used as ship propulsion systems . On warships, where economic considerations take precedence over other requirements, there are sometimes different engines, such as CODLAG propulsion , nuclear propulsion or various forms of electrical propulsion for submarines . Piston steam engines are a thing of the past, steam turbines are practically only used in oil tankers . Gas turbines and nuclear drives have not been able to establish themselves in civil shipping. However, today new cruise ships that want to call at ports in Alaska in the USA are being equipped with gas turbines again. The advantage is the almost non-existent emission of soot particles.
Ship engines are divided into high, medium and low speed engines on the one hand, and two and four stroke engines on the other. Two-stroke engines are always slow runners. The greatest achievements are made by slow runners. A diesel engine with 98 MW weighs approx. 3300 t and has the following dimensions: L approx. 32.3 m, W approx. 12 m (including platform), H approx. 14 m. Such motors are used as drive for container ships , which have a carrying capacity of approx. 10,000 TEU .
In the Emma Mærsk class (14,770 TEU), a 14-cylinder diesel engine of the type Wärtsilä / Sulzer 14RT-flex96C with 108,908 hp will be installed instead of the previously widely used 12-cylinder in-line diesel engine with 90,000 or 93,000 hp. The propeller has a diameter of approx. 10 m and weighs around 130 tons, in order to convert the greater engine power into propulsion at the same engine speed (94-104 / min).
Are even bigger
- the CMA-CGM Marco Polo type - 80,080 kW (108,878 hp)
- the triple E class - 2 × MAN two-stroke diesel engines - 59,360 kW (80,707 hp)
Economic importance of shipbuilding
The international shipbuilding market in the field of standard ocean-going cargo-carrying ships has been a subsidized market for decades, as various states pursued economic and development policy goals here. In addition to Japan, South Korea and China are now dominating the market. In some cases, Asian shipyards - supported by state subsidies - offer ships on the market at less material costs, mainly of technically undemanding ship types. For example, bulk carriers and tankers cannot be manufactured at competitive prices in Europe. The countries of Europe and North America reacted differently to this:
- Complete withdrawal from shipbuilding,
- Restriction to naval shipbuilding (warships) and repair services,
- Specialization in complex, valuable high-tech ship types, such as cruise ships , yachts and ships with special tasks,
- Engineering services without manufacturing.
- Specialization in marine equipment
The International Metalworkers Union has also been organizing shipbuilding conferences since 1951 in order to use coordinated union strategies to reduce competition to the disadvantage of the employees - but without sustainable success. Despite difficult market conditions, more than 350 shipyards in Europe employ a good 100,000 people and achieve an average annual turnover of around 15 billion euros. Some formerly important shipbuilding nations, such as Great Britain and Sweden, no longer have shipyards for the construction of large seagoing ships after a shipyard crisis . However, the shipyards in these countries also experienced an upturn in the 2010s. This is primarily due to the specialization in military shipbuilding as well as the increasing importance of maintenance, repair and conversion of ships. They also find market niches in the construction of offshore wind farms in the North Sea and the Baltic Sea .
A wide range of shipyard and ship types could be maintained in Germany, Spain, Italy and Poland. In Germany, for example, the Meyer shipyard in Papenburg has made a name for itself as a provider of highly developed cruise ships and others in the construction of large yachts, and the Howaldtswerke-Deutsche Werft in Kiel as a leading developer and manufacturer of conventional submarines. (For more details see also shipbuilding in Ostfriesland and Papenburg , list of well-known shipyards ) European shipyards benefit from their flexibility and their experience. State subsidies in Europe have expired since 2005; Support for shipbuilding is only possible through OECD- compliant funding instruments for research, development and innovation.
Until 2008, the construction of inland waterway vessels in Europe experienced a technological and economic boom due to new types of ship, such as river cruise ships and container ships. In Germany there are more than 50 inland waterway shipyards for new construction and repairs. In contrast, cargo-carrying barges are mainly built in low-wage countries such as Romania and China and only equipped in Europe, for example in the Netherlands.
Impulses for research and development arise
- from striving to further reduce ship losses at sea
- the avoidance of environmental disasters caused by damaged oil tankers and (after the Exxon Valdez accident in 1989, the number of new buildings with double hulls increased significantly)
- by building ever larger container ships
- by the increased oil price (with which the price of heavy oil correlates); this makes consumption-reducing measures on the ship's hull , ship's engine and ship's propeller more attractive and more profitable.
Leading trade fair
The world's leading trade fair for the shipbuilding industry is SMM (shipbuilding, machinery & marine technology). It takes place every two years (in "even years") in Hamburg . SMM organizes subsidiary trade fairs in Mumbai (India) and in Istanbul (Turkey).
Industry associations and representations are among others
- the VSM (Association for Shipbuilding and Marine Technology) and
- the CESA ( Community of European Shipyards Associations - shipping industry of 16 European countries).
Apprenticeships and studies
The craft of shipbuilding can be learned in Germany in the training course “ construction mechanic in shipbuilding”.
There are also special courses of study at some German universities, including at these universities:
- Kiel University of Applied Sciences : Shipbuilding and Maritime Technology (Bachelor of Engineering / Master of Engineering)
- Technical University Hamburg-Harburg Shipbuilding (Bachelor of Science) and Shipbuilding and Ocean Engineering (Master of Science)
- TU Berlin Transportation with specialization in ship and marine technology (Bachelor of Science) and ship and marine technology (Master of Science)
- University of Duisburg-Essen mechanical engineering with specialization in ship engineering (Bachelor of Science) and ship engineering and marine engineering (Master of Science)
- Bremen University of Applied Sciences in Shipbuilding and Ocean Engineering - national and international degree programs as well as studies in a practice group (Bachelor of Engineering / Master of Engineering)
- University of Rostock Shipbuilding (Bachelor of Science) and Shipbuilding and Ocean Engineering (Master of Science)
- University of Emden / Leer Here you can study the focus "Ship and Environmental Engineering" in the Maritime Technology and Shipping Management (B.Sc.) Department of Maritime and Maritime Sciences . A deepening of what has been learned is possible in the international Master's degree in Maritime Operations (M.Sc.). The focus is on innovative ship propulsion systems with Flettner rotors and offshore technologies.
- Ship dimensions
- Development history of the sailing ship
- Environmental protection in maritime shipping
- Traffic engineering
- Ship surveying
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- Association for shipbuilding and marine technology (Hamburg)
- Association of German Shipowners (Hamburg)
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- See Johanna Wolf Answers to a Globalized World. The International Metalworkers Union and the Shipbuilding Industry , in: Work - Movement - History , Issue I / 2017, pp. 45–60.
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