Kaschper Racing Shells is proud to introduce the 2003 BioRig 8+ w/Bio Slide Coxswain! The BioRig theory of mechanical efficiency* and physical stress reduction has proven itself in the last four years with a terrific competitive record as well as coach/rower support of our Bio Rig Fours. We now have in production a BioRig Eight with another innovative concept - BioSlide - which we expect will garner equal success.
The driving principle behind the Bio Slide is momentum conservation.
With every stroke the torsos of the crew move over the length of the station from stern to bow and back. Coupled with the power application during the drive, the result is a periodic velocity profile which alternates between minimum velocity (early drive) and maximum velocity (late recovery.)
The BioSlide capitalizes on the realization that drag is proportional to the square of velocity: by minimizing the maximum speed and maximizing the minimum speed of the shell the total drag is reduced, raising the average speed.
This is achieved by moving the coxswain out of phase with the crew: as the crew approaches the catch (and the stern), the coxswain is fully compressed (approaching bow). During the drive, the crew moves into the bow, while the coxswain pushes into the stern. An echo effect is created in which the stroke and coxswain mirror each other's movement along the centre line of the shell.
The result is a counterbalance of momentum - the coxswain's body weight offsets some of the crew's momentum relative to the shell, allowing the velocity curve to align more closely with the power application curve of the crew, so that the minimum speed is increased (due to the coxswain moving towards the stern during the drive), and the maximum speed is decreased (due to the coxswain moving towards the bow during the recovery). Consequently, the total drag decreases, because the peak drag decreases more than the minimum drag increases due to the previously mentioned velocity-square relationship.
This effect decreases in significance as crew weight increases, so that a Women's LW4+ stands to gain more than a Men's HW8+. Note should be taken, however, that the BioSlide requires an athletic coxswain capable of managing the traditional duties in addition to the physical routine not dissimilar to that of the crew: just like any rower, the coxswain must be synchronized fully - albeit perfectly out of phase - to ensure a smooth-running boat without check.
The BioSlide is a concept relevant to crews operating at the very top level and cultivating marginal improvements in order to reach their absolute peak potential in races where inches or feet can differentiate between victory and defeat.
The BioSlide is a drop in unit which can be removed. This convertible feature provides the option for the traditional fixed coxswain's position or the new BioSlide concept in the shell.
Hydrodynamic & Structural Design by Jakob Kaschper [email protected]
Biomechanical Design by Christoph Lueneburger, PE [email protected]
BioRig Theory is available in pamphlet form. Contact [email protected] 519-227-4652 to receive by mail. It is also available at www.kaschper.com.