The New Slim Ellipse

Since 2009, Dreher has had aerodynamic sculling oars and has now extended this efficient shape to a slim sweep oar. This is a totally new design. Along with an overall slimmer shaft profile it has two handle sizes, an aerodynamic outboard shaft, the “Tool Free Adjustable” feature and a new blade shape that maintains the contour of the proven “Apex” with enhanced hydrodynamics. The shaft transitions from a slimmer circular shaft from the handle/shaft interface to just beyond sleeve/collar adjustment, to an even slimmer elliptical shape where a new hatchet shaped blade similar to the proven successful Apex Sweep blade, but slightly different in length and with a rounder inboard edge. This hatchet is slightly longer then the Apex 52, due to the contour that fits it organically to the smaller elliptical shaft.

This oar shaft is composed of a mix of standard modulus and high-modulus unidirectional pre-preg carbon to maintain the necessary stiffness when using the slimmer shaft, which is similar in dimensions to our sculling oars,which are also elliptical in shape.  There in lies the name:  Dreher “Slim Ellipse“.  The shaft has two stiffness levels available. They are the “standard stiffness” with a deflection of ~4 cm and “less stiff” with a deflection of ~5.5 cm.

Presently we have two handle sizes: small 3.9 cm diameter and medium 4.1 cm diameter and offer the standard Row-Wik Wrap in four colors: presently in Black. We also offer Wood Veneer over the small carbon handle to make a medium plus sweep handle.

 

The advantages of the slim Dreher “Slim Ellipse” are:

 

Relative Drag of Various Shapes of the same frontal area727x600_300RDreher Slim EllipseLess air resistance drag on the recovery due to the slim elliptical shape of the Dreher “Slim Ellipse” relative to other brands of oars.(see shape chart on the left) The elliptical shaft results in a reduction in oar drag in the feathered position relative to a similar round shaft.  This air drag reduction will be proportional to the square of the angular velocity of the oar on the recovery, which is the sum of the boat velocity and angular velocity of oar shaft during the recovery. Assuming proper technique on the recovery the boat will accelerate to its maximum velocity just before the oars squares up prior to the catch.  Head to head oar tests in the lat two years in 8+, confirmed by recent race results allow us to confidently expect approximately a 3 second advantage in both the first 500 and the last 500 of a 2000 m race, (start and sprint) and about 2 seconds in the middle 1000.

 

 

Less overall weight of each slimmer elliptical oar versus our “Classic Sweep Oar” with the larger diameter shaft of the same length and stiffness.

 

Tool Free Adjustment so that each oar can be adjusted on the water in less then a minute. When adjusting on the water in fours and eights, it is advisable to adjust the oars in pairs so that the oar can be partially “shipped in” to make the adjustment more easily without having to reach out to the lock. We presently only offer the sleeve/collar in a new premium, proprietary blend of Nylon and Carbon. If the adjustment is only made by the coach on-the-land, the adjustment time, is still much faster then all current available alternatives.

 

 

 

 

dreher_ellipse_with_apex_e_blade_600x600_300rdsc_600x600_300r_0851

sweep_ellipse_600x600_300r_0831Organic transitions from one component to another, with regard to elliptical shaft and elliptical blade interface thereby enhancing the aerodynamic features off the blade and lower shaft where the oar rotational velocity is the fastest out of the water and the hydrodynamic features of the blade at the finish to minimize the water drag friction associated with the water flowing from shaft end to the blade tip. Dreher oars have the smoothest interface of any of the three major oar suppliers and therefore less energy is lost on every stroke.

 

 

Summary of Options:

  • Two Levels of Shaft Stiffness: Less Stiff or Standard Stiffness;
  • Grip Type: Row-Wik over Small / Medium carbon handles or Wood Veneer over Small handles;
  • Two Grip Colors: Black or Wood;
  • Oar Length Inboard:  371/114, 374/114 or Call;
  • Quick Adjusting – Tool Free Adjustment (TFA), with two price points of sleeve/collar material: A great time saver for coaches.

 

 

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