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Technique Feature: Control Blade Depth for More Effective Drive
by Charlotte Hollings, Calm Waters Rowing
posted on May 9, 2017

Flat grip, hands low

As we get back on the water, one of the most common mistakes I see is burying the blade too deep. There are many reasons for this but the result is the same - a less effective drive. And if the blade is going deep while you're rowing steady state, it's almost certain to go even deeper when you up the pressure.

If you're not sure if this is something you do, just take a look at the shaft of the oar at any point during your row. If the water line is halfway or further up the shaft, you're digging. From my experience, it's impossible to keep all of the shaft dry, but if you can keep the waterline below a third of the way up the shaft, you're doing pretty well.

Good grip, nice blade depth middle of the drive

Ideally, we want only the blade to be buried on the drive. With the boat set and the blades squared, gently take any pressure off the oars and see where the blades float. A Concept2 blade will float just slightly out of the water, as will a Croker blade, while Drehers tend to be completely under the water. Assuming your pitch is correct, once the blades get buried at the catch, it should stay just below the surface of the water until right before the release.

I find there are four main causes for digging. First, check your grip. If your hand is so far around the oar handle that your wrist is cocked up, you're more likely to pull up. You're also more likely to actively pull, rather than hang, with your arms during the beginning of the drive. Adjust your grip so only your fingers touch the handle and the wrist is level when the blade is squared.

Second, don't try to force the blade in the water at the catch, ie don't "chop" at the water. It is simply too easy to go deep so instead of making an effort to lift the handle, try to unweight your hands. Gravity will drop the blade in and the engineering of the oar is such that it will find the right depth on its own, given that you don't force it to go somewhere else. Where all of this gets particularly difficult is as we start to row with more power, then we need the catch to be quick without it being too hard - a fine balancing act.

Good grip, hands low, catching with the forearms (note the elbows)

Third, don't start the drive before you catch. Often the catch becomes part of the drive, hence too much pressure put into the catch. We coach the catch as being separate from the drive. Catch then drive. If you catch and drive, invariably the body goes up and with it the arms and the oar, making the blade go deep. Try to keep the body still, catching with the forearms, leaving the body in position to work the drive.

Catching with the body

Fourth, too much tension in the shoulders. It is guaranteed that the shoulders are higher than the hands so too much emphasis on the shoulders will cause an upward force that will drive the blade deep. Instead, put the emphasis on your core right at the oarhandle height, to get a solid, horizontal drive.

Here are a couple of drills I have found useful:
-Try rowing with almost no pressure. This will allow you to see the path the oars will take if you don't exert any up or down pressure. Just float the hands on the oar/s, keeping them level so as to keep the boat set.

-Another drill is to try rowing with the blades half buried. You'll have to literally push down slightly on the oar handle to keep the blade from burying completely. Most people manage to not over-bury the blades while doing this drill but rarely on the first attempt do they actually keep the blades half buried, despite feeling that they're not putting any upward pressure on the oar. It will allow you to see just how little pressure it takes to find the correct depth.

Hands very high, especially left hand

Comments

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IanRandall
05/21/2017  10:28:57 AM
A trial is currently underway in Australia on a new oar design to eliminate all contact between the oar shaft and the water. The hypothesis of this new blade design is reflected in this articles concern for the inefficiencies of a buried oar. Oars shafts contribute to boat speed as a lever. Both Croker and Concept II have attempted to make their oar shafts as thin as possible, to limit the drag when the oar engages with the water. Why not eliminate this drag effect completely? Preliminary results of this trial are showing time and efficiency gains by applying a Hydrofoil to the top edge of the blade. See https://hydrofoiloar.blogspot.com.au for details of this 'open' research project.

carlozezza
05/10/2017  3:52:24 PM
Nobody explains why blades should be pulled just below the surface. Valery Kleshnev's BioRow "target" drawn from Olympic sculling champions shows blades going deep and staying deep, following an almost square path (Kleshnev's target depth shows 6ยบ shaft angle, i.e. about a foot of the shaft above the blade is buried).

Remo
05/12/2017  3:24:42 PM
Having thought about the matter more, having the water ride half way up the shaft(~ 3 ft) is pretty much limited to inexperienced scullers. Here is an example of the port oar being way to deep ( https://pbs.twimg.com/profile_images/584712811844136960/5hR00hCa.jpg ). Having the water ride up the shaft one foot--which is what you cite from BioRow-- is normal. It would put the top edge of the blade an 1 in./ 1-1/2 in. below the surface which is just about right. For a good example see, e.g., https://www.youtube.com/watch?v=67Jqvum3L2kz (Men's 1x final, Rio Olympics) ... If you are too shallow, air will slip in behind the blade: This is called cavitation and/or flow separation. It will reduce the effective surface area of the blade and hurt your efficiency.

rkesor
05/11/2017  12:12:24 PM
The idea is that the water near the surface has less internal tension than the slightly deeper water. Burying the blades deeper during the drive will prevent them from "slipping" as much as they would if they were buried shallower. This higher blade efficiency cancels out any extra drag caused by looming the oar. That is the reasoning behind it. I am not a practitioner of it due to the negative effects that is has on the cleanliness of the finish.


Remo
05/12/2017  4:05:47 PM
@rkesor, You have the concept correct, but you miss some of the foundation. The reason to go deeper is that the water pressure at the top edge of the blade increases as you go down (not the lessening of internal tension of water). This increased pressure prevents cavitation (which is caused by low pressure) behind the blade and it is cavitation which reduces the blade's efficiency. Once you get deep enough, you don't need to go any deeper. And yes, I am in complete agreement with you that a clean release is really important and going too deep can impair the release.

Remo
05/10/2017  7:05:08 PM
1. Relative to the water, the shaft is going the opposite direction as the blade: most of the shaft will be pushing the water forward not backwards. The more shaft in the water, the more drag, the slower the boat. 2. It gives you a bad finish with the blade getting caught a bit on the release..... That said, going too shallow is just as bad or worse: you get wash out and/or cavitation (ripping the water) which slows you down too..... Just make sure that you get the blade covered and deep enough so that you don't rip the water and don't get caught at the release. A little water running up the shaft is not a problem, but a lot is. ;-)




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