Boom (boat building)

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Oarlock on the boom
Boom with “5. Strebe “on a double scull
Wide rowing boat without an outrigger: the oarlock sits on the side

An outrigger is a construction on narrow rowing boats with which the oarlock is attached at the required distance from the rowing boat.

Since certain standard values ​​must be observed for the distance from the oarlock to the rowing area, the narrower the boat, the longer the jib must be. Outriggers for belt boats are larger than those for scull boats because the oars are longer than the sculls . In the case of wide rowing boats, no outrigger is necessary and the oarlock is located directly on the ship's side ("inrigger").

When designing booms, factors such as high torsional rigidity, low dead weight and easy adjustability play a role.

attitude

On most of the booms, the setting of the rowing area can be adapted to the rower ("trimming"). The height of the boom influences the oarlock height and is used to adapt to the body weight and height of the athlete. The oarlock spacing, which describes the lateral distance between the oarlock pins and the keel of the boat, is also adjusted via the boom and must be set depending on the boat class and the level of performance of the athletes.

Boom types

Various concepts can be used to construct the boom.

Conventional tension strut boom

Until the 1980s, there was almost only the conventional boom, which was built from two to four struts and mounted on the side of the hull. It was initially made of iron or steel , later also of aluminum and is still often in use today due to its simplicity. In addition to one or two struts that run almost perpendicular to the hull, the force is primarily transmitted via one or two tension struts that point diagonally towards the stern . To increase the boom rigidity, a so-called “5. Strut "mounted, which is attached to the oarlock pin above the oarlock, points to the bow direction of the boat and transfers pressure forces. The designation “5. Strut “goes back to the fact that the boom itself consisted of four struts for a long time and is also used for booms with fewer than four struts.

Roll boom

The idea of ​​the roller boom was invented and patented in the 19th century, but could not be implemented satisfactorily for a long time. At the beginning of the 1980s it was used successfully for the first time by Volker Nolte and Peter-Michael Kolbe , among others , but was banned again a short time later by the World Rowing Association .

Wing arm

However, with the development of the roll boom, an improvement in the boom concept in general began, as the so-called wing boom was also invented at this time . This is not mounted on the side of the boat, but on the boat and thus increases the distance between the outriggers and the water surface. This makes the rowing boat more robust against the impact of waves. The wing arm described here usually consists of a single tension strut made of aluminum or carbon fiber composite materials and is usually characterized by the so-called “5. Strebe "added. In modern racing rowing boats, the use of wing arms often means that the installation of frames can be dispensed with, as the boat hull is self-supporting and the forces acting on the boom no longer have to be transmitted through frames. Rowing boats with wing arms are therefore considerably more torsion-resistant than those with conventional arms, which is expressly desired in racing rowing . In terms of width, they have prevailed since the Olympic rowing regatta in 2004 , and have largely displaced other types of outriggers in racing rowing . The name of the wing arm goes back to the similarity to wings on a high- wing aircraft .

Print boom

In the 1990s, the conventional tension strut brackets were replaced by new types of compression brackets made from composite materials. The carbon fibers could also transfer the forces that occurred in the direction of pressure and allowed a more direct transfer of the forces exerted by the rower to the hull. A "5. Strut "to absorb compressive forces is not necessary with this boom. Like the conventional booms, the pressure booms were mounted on the side of the boat. Due to the use of carbon fibers, pressure booms are not very robust against damage and are also difficult to adjust. Apart from racing, they have and had no meaning.

Pressure wing jib

The latest development in the area of ​​the boom is the so-called pressure wing boom . Like the wing arm, it is mounted on the boat, but as a pressure strut. It is made of carbon fiber and is currently only available for scull boats, where the forces exerted by the rower act symmetrically on both sides of the boat. A "5. Strut "to absorb compressive forces is not necessary with this boom.

literature

  • Wolfgang Fritsch: manual for rowing . 4th, revised edition. Meyer & Meyer Verlag, Aachen 2006, ISBN 978-3-89899-111-7 , p. 47 .

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