Rudder blade
The flat end of a skull or oar in rowing is called the rudder blade .
description
During the pressure phase of an oar stroke, the rudder blade stands upright in the water and approximately represents the pivot point of the rudder, which is regarded as a one-sided lever . The rower can exert a propulsive force on the hull via the oarlock . It is often wrongly assumed that the blade is the end of the load arm and the oarlock is the pivot of the oar.
In the overwater phase of the stroke, the rudder blades are usually turned flat and free of the water in order to reduce the resistance to movement against air and water.
Manufacturing materials
Various manufacturing materials can be used to manufacture a rudder blade. Up until the mid-1980s, sculls and oars were largely made of spruce, which was also the case for the rudder blades. After the Concept2 company developed new oars with a carbon fiber shaft and thus made asymmetrical blade shapes possible, new manufacturing materials quickly became established. These promised greater robustness with simultaneously lower weight and a more efficient blade shape. Modern rudder blades are made of plastics.
Designs
The design of rudder blades is only limited by a few regulations. For safety reasons, according to the "Rules of Racing" of the World Rowing Association, the blades of the oars must be at least 5 mm thick, those of the sculls at least 3 mm. In addition, there are no structural restrictions, so that the further shape is largely determined on the basis of knowledge about the drive efficiency of different blade shapes, but also of rowing requirements. Since particularly efficient blades also place high demands on the condition of the rowers, there is now a wide market with very different blade shapes for special application scenarios.
The rudder blades available for racing rowing have primarily been optimized under fluid dynamic aspects in order to achieve the greatest possible efficiency (low slippage in the water). Associated with this is a trend towards larger blades with a simultaneously decreasing total length of the oars. Further optimization parameters are the leaf curvature and profile. The optional attachment of a so-called "vortex edge" in the form of an additional CFRP strip on the outer edge of the rudder blade also serves to improve the rudder blade efficiency.
The most important basic types of rudder blades are described below.
Macon leaf
Symmetrical rudder blades with a so-called rib on the front of the blade are called “Macon blades”. This blade shape developed into the standard at the European Rowing Championships in 1959 in Mâcon, France . The rowing trainer Karl Adam from Ratzeburg developed a whole series of new blade shapes as a further development of much older rowing blades in the 1950s. Since his Germany eight with the new blades in Mâcon won the gold medal convincingly, his ideas prevailed. The older leaf shapes previously used also had a symmetrical shape, but were considerably longer and slightly narrower than the new Macon leaf.
As a smaller and therefore lighter of the common designs, the Macon blade is the prescribed rudder blade for children . In popular sports and touring rowing , this blade shape is also the most commonly used shape to this day.
Depending on the manufacturer and type, a Macon blade intended for belts is around 58 cm long and between 16 and 18 cm wide and has an area of around 971 square centimeters. As a smaller version for skulls , it is around 50 cm long and around 14 cm wide with an area of around 695 square centimeters.
Big blade
With the use of new manufacturing materials by Concept2 from around the 1980s, asymmetrical blades with a rib on the front could be built for the first time: the so-called "big blades" (also referred to as: shovel, cleaver, cleaver or simply blades). The idea for this was much older, so around 1880 the asymmetrical "Davis sheet" already existed. In the timber construction, however, asymmetrical leaves could not be made usable.
The technical developments also led to a change in rowing technique. The lossy pitching movement caused by the levering was reduced by basically lighter oars. The Big Blades themselves made faster turning points of the rudder blades and at the same time a clean lifting out of the water necessary. With a very good rowing technique, the Big Blades offer an advantage of around 1 to 2% over the Macon blades.
Depending on the manufacturer and type, a belt blade is between 50 and 60 cm long and between 20 and 30 cm wide. It has an area of about 1100 to 1200 square centimeters. A skull sheet is around 44 cm long and around 22 cm wide with an area of around 780 square centimeters.
In addition to the original Big Blade, other secondary types have become established over time. The background to this fact is that the already good blade efficiency of the big blade can be improved even more by making small changes. By omitting the rib on the front of the blade and changing the blade curvature, the slip in the first part of the oar stroke is reduced, the blade is more efficient. These types are also known as "Smoothie" and "Fat Blade".
Painting
The rudder blades used in racing oars are mostly painted in special colors, for example in club design or in national colors on an international level .
On the one hand, oar blades are painted in different colors in order to be able to distinguish the rowing boats during a rowing regatta even from a distance. On the other hand, it is important to be able to identify your own sculls and straps quickly in order to avoid accidental mix-ups.
Web links
- Historical development of sculls and oars with details about the rudder blade on the website of the German Rowing Association
- History of boat technology on rowinghistory.net (English)
- Oarspotter.com (Directory of Many Oar Blade Designs)
Individual evidence
- ^ FISA Rules of Racing. World Rowing Association , accessed on February 6, 2015 .
- ↑ The Vortex Edge. Concept2 , accessed May 22, 2013 .
- ↑ Regulations on rudern.de. (No longer available online.) Archived from the original on May 18, 2013 ; Retrieved December 26, 2012 . 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.
- ↑ Macon sizes at the manufacturer Concept2.de. Retrieved May 22, 2013 .
- ↑ Big Blade sizes on Concept2.de. Retrieved May 22, 2013 .
- ↑ The smoothie on concept2.de. Retrieved May 22, 2013 .
- ↑ Thomas Kleinfeldt: Skulls swapped at the DJM in Cologne. (PDF; 602 kB) (No longer available online.) In: rudern.de. German Rowing Association, archived from the original on March 7, 2016 ; Retrieved July 12, 2013 . 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.
