Surging Forward

Surging Forward is a fascinating website by a Canadian oarsman, Andrew Sliasas. Andrew has a Masters degree in Mechanical Engineering and has done extensive research on the hydrodynamics of the oar blade. It's complicated stuff but, on his website, he explains his methodology and presents his results in layman's terms and draws some interesting conclusions some of which are excerpted here with emphasis added where appropriate.

Blade Shape

"Comparing handle force curves during the drive portion of two identical strokes, one using the Concept2 Smoothie [Ed: Smoothie2 Plain Edge] and one using a Concept2 Fat2 we see that the Fat2 loads up quicker after the catch. Towards the release, the Smoothie has a slightly higher loading."

"Looking at the path of the blade through the water, we see that the Fat2 slips less than the Smoothie (that is, overall the Fat2 moves less towards the stern of the boat). In practical terms, this means that the Fat2 has a stronger grip on the water - especially at the catch."

"Finally, when we compare the instantaneous propulsive efficiency of the Fat2 and the Smoothie during the drive, we see that the Fat2 has a higher efficiency through most of the stroke."

"Taken over the whole drive the Fat2 is approximately 1% more efficient than the Smoothie. Overall, all things being the same, the Fat2 will finish a 2k race approximately 2 seconds faster than the Smoothie."

Oar Length

"Generally, a more efficient blade shape will have a centre-of-pressure located closer to the blade tip. Going back to the Smoothie and Fat2 comparison, this means that the higher efficiency Fat2 should be geared lighter than the less efficient Smoothie in order to produce a similar loading for the rower." [C2 recommends oar length be shortened by 4-8 cm compared to the Smoothie.]

Shaft Stiffness

"Because a more efficient blade (Fat2) – which has a better lock in the water – has less negative slip than an inefficient blade, it should be fitted with a more flexible shaft than a less efficient blade (Smoothie) to produce a similar loading profile for the rower."

Rigging

"... the first half of the drive is characterized by a high lift force acting on the blade. This lift-generated force in turn leads to a high blade propulsive efficiency. This efficient lift-effect can be enhanced by encouraging a larger catch angle."

"Several rigging modifications can be applied to take advantage of blade lift during the early part of the drive:

- Moving the foot stretchers towards the stern

- Increasing the work distance through the pin (horizontal distance from the stern-most edge of the seat at the catch to the oarlock pin)

Changes to the rigging should not take place in isolation, and should be accompanied by appropriate adjustments to the rowing technique."

Adjustments to Rowing Technique

Effort Focus

"Focusing on the first half of the drive - encouraging both high power application and clean technique - may contribute to a faster boat speed. Some potential areas to focus on:

- A long reach at the catch, with

- Blades dropped in the water cleanly and sharply, and

- A strong leg drive initiated immediately after the blade is fully submerged"

Blade Entry and Extraction

"Confirming what is often observed from the coach boat, by analyzing real-time rowing data (boat speed, oar angle, oar handle force, etc.) obtained from high performance athletes on-water, there was a pronounced 'rowing in' of the blade at the catch. In other words, the time (and angle) from maximum oar reach with the blade fully above water to the time (and angle) when the blade is fully buried and applied force is noticeable. This is generally caused by a slow rising of the hands combined with the initiation of the leg drive before the blade is sufficiently buried.

"In order to maximize the efficient lift-effect on the blade that occurs early in the drive, the blade should be sharply inserted in the water quickly after maximum reach while trying to match the speed of the blade to the water. This catch produces a distinctive V-shaped splash as the blade enters the water. As soon as the blade is locked in the water, the power application of the drive should begin.

"A similar ‘rowing-out’ is often seen at the end of the drive. During this part of the stroke, however, the blade is its least efficient (not to mention the weakest rowing muscles are being utilized.) At the end of the drive, then, it might not be as imperative to sharply remove the blade from the water as it is going in at the catch. A gradual row-out (but not a wash-out) is also more comfortable for the rower, and is aided by the low pressure region that develops behind the blade during the stroke."

Blade Depth

"A general guideline for blade depth through the drive is to have the top edge of the blade either flush with the surface of the water, or slightly below. Some argue, however, that a deeper blade helps with balance/stability during the drive - especially in smaller boats.

"Comparing simulation results for a blade with its top edge at the surface of the water with those for a blade buried 10 cm below the surface of the water, an increase of over 1% in propulsive efficiency is seen for the more buried blade. However, the simulation does not account for the extra part of the shaft that is below the waterline and the extra time/effort needed to get the blade in deeper at the catch and out at the finish.

"Also, a side note is that a deeper blade will have less slip - meaning all things being equal, a deeper blade will feel heavier for the rower."

Do yourself a favor and go to Andrew's website to learn much, much more. /MM