Tail shape
The shape of the stern of a vehicle - especially a ship or boat - is referred to as the stern shape .
A stern (from the Low German hek for “ Umfriedung ”, “Umhegung” or from the Old High German hegga = cherish, enclose, fence around) is the name for the rear part of the vehicle. The term “stern” was coined in the shipping industry , at times when the rear part of the ship was mostly raised and enclosed with a bulwark (a massive, parapet-like or wall-like continuation or elevation of the ship's side) that resembled a “enclosure”.
Basic stern shapes of ships
According to the extent of their stern, a distinction is made today in ships and boats between the basic transom (or flat), round and pointed (see also Gatt ) :
A Plattgatt or transom is the Heck type of ships or boats, having a flat rear end plate (the so-called. Mirrors have). The mirror is either vertical, protrudes “at an angle” over the water or is inclined inwards (more common on modern yachts).
Even in modern cargo shipbuilding, smooth, vertical stern were built almost without exception since the 1980s, until a combination with the cruiser stern prevailed. The term "Plattgatt" is no longer common for modern cargo shipbuilding, instead (only) the transom is spoken of.
Modern sailing ships and sailing boats such as dinghies and dinghy cruisers as well as motor boats often have a transom.
There are several special forms of the transom stern: A special form of the transom stern is the so-called yacht rear (also: Boat stern ) of many regatta awnings jachten whose oblique mirror extends from the water surface schiffeinwärts. Another special case is the “cut off cruiser stern”, a combination of cruiser stern ( see below ) and transom stern. The stern of inland waterways vessels, the lower part of which arches like a tunnel, is referred to as "tunnel stern".
A round ship's stern is called a round gatt . The designation "Rundgatt" includes several sub-forms according to the respective shape and position of the stern steved (rear boundary of the ship's hull, in the extension of the keel ). These include the elliptically shaped steamer stern of older ships and the tug stern. A further sub-form is the cruiser rear (literally translated from English. Cruiser star ), characterized by an S-shaped stern, which extends above the side wall toward inside. The cruiser stern is designed to provide protection against rising seas and is also more efficient due to a reduction in water resistance. For many years of the 20th century, the cruiser stern was the preferred stern for motor ships, from freighters to warships, but also for tall ships . In the Netherlands, a shape of the round stern, which is widespread for this region and which was used in the so-called flat - bottomed ships and which forms an almost circular closure , has been developed in the Netherlands since the 16th century . With this design, the planks meet the stern post behind the stern at an almost right angle. This form was applied to almost all vessels used in inland and non-military shipping, from fishing vessels such as the stallion or botter to river sailors such as the Tjalk and the Ewer to seagoing merchant ships such as the Galiot and the Kuff .
The Spitzgatt is a pointed stern that looks like a bow. It is used less often in shipbuilding today, but is found, for example, in some fishing trawlers . Sailing or motor yachts are referred to as Spitzgatter such. B. the Scandinavian one-class Spaekhugger .
Historic transom
Modern transom of Bro Elizabeth
Spitzgatt of Margaret Hamilton
Elliptical stern of the sailing training ship Sagres
The cruiser stern (here battleship Gneisenau ) serves not least to protect the rudder.
Developments in the cargo shipping of the 20th century
Freight shipping in particular is caught between the need for maximum speed and the greatest possible transport volume. This also led to several innovations in the area of tail shapes in the 20th century.
Older ships were initially built with a steamer stern.
At the beginning of the 20th century, the shape of the cruiser stern appeared in Denmark. The shape allows an advantageous flow of water around the stern, which leads to reduced water resistance and thus increased efficiency. This stern shape was soon preferred by cargo and passenger ships and replaced the steamer stern that had been widespread up until then.
In the 1980s, the transom stern prevailed, which in comparison to the cruiser stern offers a less favorable water flow (greater separation resistance), but more deck area. With the same main dimensions of the ship, this allows higher payloads, i.e. a larger transport volume, and also reduces construction costs.
In the case of ships, which are now getting bigger and bigger, the flow to the propeller is increasingly hindered, so that the disadvantage of the transom stern becomes more significant. In order to combine the advantages of transom and cruiser stern, stern of inland vessels are therefore mostly built in the lower part as cruiser stern, but have a mirror in the upper part. Alternatively, the flow conditions of the transom stern can be improved, for example by using a so-called downflow plate near the propeller.
Free hanging rudder of a freighter (semi-floating rudder)
Other differences from ship stern
Rudder
In addition, the stern of smaller boats in particular can also differ according to whether the rudder (the device for steering) runs in the traditional design on the outside along the stern or largely hangs freely (half or full floating / spade rudder). Regardless of this, the rudder can be visible at the stern or retracted over the water; in the latter case, the rudder is usually not visible above the surface of the water.
Ducktail
Ducktails are extensions and widening of the stern at the waterline. In the course of upgrading the equipment of the ship, they should stabilize it in the water and generate additional buoyancy.
Christian IV still without a duck tail
The same ship with a duck tail and a new name Julia
literature
- Horst Menzel: Smack, Kuffen, Galioten. Three almost forgotten types of ships from the 18th and 19th centuries. (= Writings of the German Maritime Museum , Volume 47.) Kabel, Hamburg 1997, ISBN 3-8225-0413-0 .
Web links
Individual evidence
- ↑ a b glossary: H. bsu-bund.de , archived from the original on September 28, 2007 ; Retrieved July 8, 2016 .
- ↑ His Eileen (1998): Fishing on England's East Coast. Modell Werft, 6/98 and 7/98 (accessed February 20, 2007)
- ↑ a b Jobst Lessenich: Shipbuilding - New Ship Shapes ( Memento of the original from March 12, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . At dsm.museum, accessed on July 8, 2016 ( PDF ; approx. 4.25 MB)
- ^ Ernst Müller: Schiffbaukunde , Salzwasser, Bremen 2010, ISBN 9783861951681 . P. 51 ( Online . At books.google.de, accessed July 8, 2016)
- ↑ a b c P. Engelkamp, HH Heuser, B. Holtmann, T. Jiang, O. Kammertöns, E. Müller, V. Renner, J. Zöllner (2004): From the shipbuilding research institute to the development center. 1954-2004. 50 years of research and development for inland and coastal shipping. DST. Development Center for Ship Technology and Transport Systems eV ( Development Center for Ship Technology and Transport System ) ( Memento of the original dated August 6, 2007 at the Internet Archive ) Info: The archive link is automatically inserted and not yet tested. Please check the original and archive link according to the instructions and then remove this notice. (Institute at the University of Duisburg-Essen ) (accessed on February 20, 2007)
