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 than 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.  Therein 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  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 the 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 last two years in 8+, confirmed by recent race results allow us to confidently expect up to a 3-second advantage in both the first 500 and the last 500 of a 2000 m race, (start and sprint) and up to 2-seconds in the middle 1000 depending on the technique and synergism of the crew size of the boat.

 

 

The overall weight of the Slim Ellipse oar is noticeable lighter 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 than 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 currently available alternatives. Recent enhancements a new Nut Locker Clamps that also aid in the ease of adjustment.

 

 

 

 

dreher_ellipse_with_apex_e_blade_600x600_300rOrganic 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 the 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;
  • Handle Size: Small / Medium carbon handles;
  • Two Grip Types: Row-Wik grip wrap or Shrink-Wrap
  • Colors: Row-Wik in Black and ShrinkWrap in Red or Black
  • Oar Length Inboard:  371/114, 374/114 or Call;
  • Quick Adjusting – Tool Free Adjustment (TFA):  With or without the handle adjustment lever.

 

Summary of Successes With These Oars:

  • Fall of 2016 Boston College Collegiate 4+ Men’s raced successfully to a 10th out of 43rd place at the HOCR (Prior to the boat production release);
  • Spring of 2017 Boston College Rowing Club, Men’s Freshman 8+ won the Gold Medal at ACRA;
  • Summer of 2017 Jr Women’s USA National Team 4- won the Bronze Medal at Jr. Worlds;
  • Summer of 2018 U-19 Selection Camp 4- won the Gold Medal in Elite/Sr. that event at Club Nationals;
  • Summer of 2018 U-19 Selection Camp 8+ won the Gold Medal in the Int. and the Silver in Elite/Sr. events at Club Nationals;
  • Summer of 2018 U-19 Selection Camp 2- won the Silver and Bronze Medals in the Int. that event at Club Nationals;
  • Summer of 2018 Jr Women’s USA National Team 4- won the Gold at Jr. Worlds;
  • Summer of 2018 Jr Women’s USA National Team 8+ won the Silver at Jr. Worlds;
  • Summer of 2018 Jr Women’s USA National Team 4+ won the Bronze at Jr. Worlds.
USA 4- On Their Way To Winning the Gold JWRC 2018
USA 8+ On Their Way To Winning the Silver  JWRC 2018

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