Knowledge Base

EmPower Oarlock

EmPower Oarlock
Your Empower Oarlock can help you get the most out of each stroke. Here are some documents to get the most out of your EmPower Oarlock

Doing a Pin Calibration with the Empower Oarlock is necessary but can sometimes prove to be a little frustrating. If you keep failing the swing calibration, the SpeedCoach does not provide much feedback about what failed. We have prepared a troubleshooting guide that can help walk you through several key techniques to improve the success of the swing calibration:

Empower Oarlock Pin Calibration Troubleshooting

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Yes you do. To maximize the value and flexibility of your rowing electronics investment, the EmPower Oarlock works with any SpeedCoach GPS 2. To support the EmPower Oarlock, the SpeedCoach must have Training Pack with firmware version 2.12 or higher. If you have an earlier version of firmware, you can update your firmware at no charge. If you do not have the Training Pack, you can purchase an upgrade. Installation of updates and upgrades requires a Bluetooth Low Energy USB Dongle. If you have any other NK performance monitor, you can trade it in under our Trade-In, Trade-Up Program.

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To make the installation process as simple as possible, we created a video series that shows step-by-step-instructions for the EmPower Oarlock. If you have any further questions, please contact our technical support team

Step 1: Introduction

Step 2A: Installing on a Standard Pin

Step 2B: Installing on a C-Cup Bracke

Step 3: Pairing

Step 4: Configuration

Step 5: Calibrating your Oarlock

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Empower Oarlock Instruction Manuals

Detailed instructions to Install, Pair, Configure and Calibrate your EmPower Oarlock.


Empower Oarlock Downloads

Shows you which size bushing you would need for the various sweep and sculling boats out there.

OS X installer for EmPower Oarlock firmware version 1.01

EmPower Oarlock firmware version 1.01

Troubleshooting the Pin Calibration Process - Shows common issues why swing calibration fails

Oarlock Template Tutorial

ROWER COMPARISON TEMPLATE

Representative Oarlock Values by Class and Skill Levels

WORKOUT STROKE PROFILE TEMPLATE

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You will first need to create an account if you do not already have one. After you create an account, sign in. Click on your account name at the top of the page and select My Account. On the left of the screen, you will see Product Registration, select this option. Enter your purchase date, serial number and product name into the fields and then select Save.

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The oarlock measures both the angle of the oarlock and the force being applied to the face of the oarlock. These measurements are taken 50 times per second and are then used by the oarlock to calculate per-stroke parameters which are transmitted to the SpeedCoach wirelessly. These measurements are ones that have been proven to be most helpful in evaluating and improving rowing effectiveness:

Measurements
MetricUnitsRangeNotes
Catch Angle Angular Degrees Angle of the oarlock when direction of motion reverses from recovery to drive direction.
Effective Length Angular Degrees Total degrees traversed by the oarlock between the 100N for sculling/200N for sweep slip and wash thresholds.
Finish Angle Angular Degrees Angle of the oarlock when direction of motion reverses from drive to recovery direction
Force Newtons to 1/10 The force applied to the oarlock face averaged over the full stroke.
Max/Peak Force Newtons to 1/10 The maximum force applied to the oarlock face at any point in the stroke.
Peak Force Angle Angular Degrees The degrees of angle at which the peak force occurred in the stroke.
Power Watts to 1/10 The rate of work being output. Power can be increased by doing more work per stroke, or taking more strokes per minute.
Average Power Watts to 1/10 Power per stroke averaged over the entire interval (if using a SpeedCoach). Resetting the clock will reset the average power.
Slip Angular Degrees Angle degrees traversed by the oarlock before the force exceeds 100N for sculling/200N for sweep - a threshold below which the work being done on the oar is doing relatively little to increase the speed of the boat.
Wash Angular Degrees Angle degrees traversed by the oarlock after the force drops below 100N for sculling/200N for sweep – a threshold below which the work being done on the oar is doing relatively little to increase the speed of the boat.
Work Joules to 1/10 The force times the length of the stroke. Work measures the effectiveness of each stroke.
Average Work Joules to 1/10 The average force times the length of the stroke. Work measures the effectiveness of each stroke.
Length Angular Degrees Total degrees traversed by the oarlock between catch and finish.
Effective Length Angular Degrees Total degrees traversed by the oarlock between the 100N for sculling/200N for sweep slip and wash thresholds.

Please also vist our Blog post, It's In The Computer: A No-Nonsense Breakdown of Rowing Tech Jargon for additional information on this topic.

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The pins in the calibration tool are removable. It’s okay to temporarily remove them from the bottom of the tool when calibrating. For example, if Pins C&D interfere with the rigger when calibrating using Pins A&B, simple pull out the pins using pliers. Do the reverse when calibrating using Pins C&D.... Read more

The minimum and maximum values for inboard and oar length are as follows:
Sweep
Oar Length: 175 cm - 500 cm
Inboard: 20 cm - 130 cm

Sculling
Oar Length: 175 cm - 500 cm
Inboard: 20 cm - 130 cm

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The magnet plate installed below the oarlock creates a magnetic field which is sensed by a magnetometer inside the oarlock. The calibration routine uses a provided calibration artifact, which is basically a protractor that clips onto the magnet bar, to "teach" the oarlock what it will sense at certain angles, ensuring that it provides measurements that are accurate for your oarlock/pin/rigger setup. Angle is displayed with whole degree resolution and is accurate to +/- 2 degrees.

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The oarlock is installed in exactly the same way you would replace the oarlock on your boat, or remove it to change pitch bushings, and you'll need the same tools your boat would require for that task (such as 7/16", 10mm and/or 13mm wrench and/or screwdriver for backstay adjustment). It can typically be installed in 5-10 minutes, particularly with familiarity. A 2.5mm Allen wrench for securing the magnet bar is included with the oarlock. It is helpful to use a long straight edge, such as a 6ft level, for aligning the magnet bar and zeroing the oarlock angle.

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Typical battery life in the Oarlock is 10-25hrs, depending on the battery and ambient temperature. We recommend high quality Lithium disposables or Low Self Discharge rechargeable NiMH batteries for more economical use. We do NOT recommend use of alkaline batteries because they are prone to leaking, particularly in a humid environment, and A LEAKING BATTERY WILL DESTROY THE OARLOCK ELECTRONICS AND IS NOT COVERED UNDER WARRANTY! Here are some batteries we tested, along with the duration they ran under typical use at 75°F:

Energizer Ultimate Lithium 25hrs
Duracell Duralock Rechargeable 2500mAh 15hrs
Eneloop Pro Rechargeable 2450mAh 15hrs
Energizer Max Alkaline 15hrs (NOT recommended!)
Tenergy Rechargeable 2600mAh 14hrs
Energizer Power Plus Rechargeable 2300mAh 13hrs
Energizer Industrial Alkaline 13hrs (NOT recommended!)
Duracell Alkaline 1500mAh 11hrs (NOT recommended!)
Energizer Universal Rechargeable 1500mAH 10hrs
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The range from an oarlock to paired SpeedCoach is approximately 100ft (30m). Simply hold or mount the SpeedCoach in a nearby motorboat to view oarlock measurements. Because each Oarlock pairs to a single SpeedCoach, you will need a SpeedCoach for each seat you wish to view. We recommend installation of SpeedCoach Surface Mounts in the launch to secure the SpeedCoach units for viewing.

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We have tried to balance viewing flexibility with ease of operation by providing two display modes:

"SKILL" mode offers pre-configured data screens that are fast and easy for athletes to use to focus on particular aspects of the stroke. The preconfigured SKILL screens are CATCH, FINISH, LENGTH, WORK, POWER.

"CLASSIC" display mode offers full flexibility to choose any data in any of the four SpeedCoach windows and is ideal for rowers and coaches who are interested in creating their own preferred combinations. For example, it is possible to see how boat speed is impacted by catch and finish angle. Or, monitor heart rate and power while maintaining rating. In CLASSIC mode you have the option of freezing the top windows to Rate and Split and changing only the bottom two, or allowing all four windows to flex.

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Force curves were made available in early rowing analysis systems because they are the most basic representation of the actual analog data from the force sensor, with no analysis applied. As a result, they're familiar, but that doesn’t mean they're ideal. Even after years of looking at and coaching with force curves, there is not much agreement in the sport about what makes a "good" force curve. (Lots of opinions, but not much agreement!) Also, it is challenging for athletes to use force curves as a target for changing their rowing, particularly without a clear target also represented on screen. We have chosen to present primarily numerical data that breaks the stroke down into clearly understood elements because we have demonstrated to ourselves, and many other coaches and athletes, that simple numbers are much easier to focus on when attempting to make changes or assess progress.

Because the EmPower Oarlock logs five key elements each and every stroke (catch angle, slip, peak force, peak force location, wash and finish angle), we are also able to present a clear "picture" of the stroke very similar to a force curve which we call a "Stroke Profile".

When charted using a simple Excel template, the Stroke Profile illustrates these key characteristics of one or more rower. In the example below, four scullers were evaluated during 20' session. We can see that Rower #2 is probably rigged too far into the bow (see their shallow catch angle and deep finish angle). We can also see that Rower #2 has their peak force occurring later in the drive than the other three. The coach can now provide Rower #2 with a target Peak Force Angle of -10 to -20° in order to better match the other rowers in the boat. Rower #2 can monitor himself as he rows future sessions.

To create your own Stroke Profiles, please see Excel Templates and instructions on how to use them below:

Empower Oarlock Downloads

WORKOUT STROKE PROFILE TEMPLATE

Empower Oarlock Downloads

ROWER COMPARISON TEMPLATE

Empower Oarlock Downloads

Oarlock Template Tutorial

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With our focus on simplicity of installation, pairing and understandability, the initial release of the system is a one-to-one pairing between oarlock and SpeedCoach. Every oarlock needs a dedicated SpeedCoach to view and log its measurements. The SpeedCoach is hardware capable of pairing to multiple oarlocks, and we will offer this option as a firmware update in the future.


But wait! I'm a sculler, and I clearly use two oars!

While it is absolutely true that all scullers have differences in their stroke between their left and right hands, these differences (a) cannot be TOO great or the boat would never go straight; and (b) are generally smaller in their impact on boat speed than the larger elements which can be captured on either side. When in sculling mode, the SpeedCoach doubles the Work and Power values obtained from the single Oarlock so the effective athlete output is shown. We are in part choosing to release the EmPower Oarlock for sculling as a one-to-one system to learn more about the typical combinations of measurements preferred by scullers so we can create a simplified and manageable user interface for displaying the MANY values available when you double the number of Oarlock measurements to be displayed. We promise you will see that the system is incredibly powerful with only one Oarlock as soon as you try it. Note that you can also swap sides occasionally to compare results because the Oarlock is so quick and easy to install and can be used on either side.

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The initial release of the system does not allow pairing of SpeedCoach units for timing comparisons in team boats. However,one of the main contributors to poor timing is inconsistent catch and finish angles between rowers. By coordinating all rowers to hit the same angles, timing is generally self-corrected.

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There are rough guidelines for what to expect (-65 and +40 for sculling, -55 and 33 for sweep), but no "perfect angles" for every situation. Angles will differ based on unchangeable variables, such as sweep vs. sculling and the height and arm span of the athlete, and changeable ones, such as rowing style, foot stretcher location, spread/gearing, and inboard. In fact, knowing angles is what allows coaches and athletes to adjust and test these variable parameters. The goal is having each athlete hit angles that maximize their effectiveness, and in team boats, having all athletes hit the same angles as closely as possible. The other measurements provided by the EmPower Oarlock assist you in making these evaluations: slip, wash, length and effective length, as well as trial and error combined with assessing the results.

Our partners at BioRow have been measuring athletes and compiling representative data for over twenty years. This Oarlock Reference Values Table summarizes representative ranges for many of the values provided by the EmPower Oarlock.

Representative Oarlock Values by Class and Skill Levels

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We adopted with the approach employed by Valery Kleshnev of BioRow, which is to use a set threshold. Clearly, that set threshold may not truly define "slip" and "wash" as we think of it for a smaller, lighter, or less powerful athlete. This threshold is also pretty much irrelevant if you’re paddling as much of the stroke will be below this value. However, if you think of these measurements more as a relative target than as an absolute target, the fixed threshold is simple and effective. For example: "I tend to lay back too far and lose my grip on the water. When I do that, my wash value is 18. When I keep my core engaged and shorten my finish slightly, my wash drops to 10 or 11 and my speed increases. I'm going to try to keep my wash value below 12 at steady state."

This discussion, in general, points out our philosophy with this product. We may not be starting with 100% perfect measurements, perfectly executed. There has simply not been broad enough access to rowing biomechanics data like this to determine the absolute best way to measure everything on day one. We teamed with Dr. Kleshnev and BioRow to ensure we had a strong, validated starting point with measurements that have helped him coach many athletes to world-record times. But, we are also sure we and our customers are going to learn new approaches from expanded use of this system, which is why we are anxious to get it on all sorts of boats with all sorts of athletes. We have been using it in our own rowing and coaching, and we have seen first-hand that these measurements make sense and work in practice. And, both the Oarlock and the SpeedCoach can be updated in the field as we continue to make improvements in the future. Alternatives here would be to make these a user-settable threshold value, or to define them as a percent of peak force. We may test these approaches in the future.

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We have put a huge amount of effort into making sure each sensor is accurately calibrated and provides consistent readings in all situations and conditions. We have not yet encountered a situation where the measurements don't make sense.

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The only C-cup riggers we have found that do NOT work are the standard Fluid Design cup, Empacher C style, and WinTech C-style pin bracket. Fluid replacement brackets that will fit the oarlock can be found here. Empacher's can use a Dreher bracket which can be found here.

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The weight difference is small (170g sculling, 188g sweep) and unnoticeable once the weight of the rower is added to the boat. However, the weight WILL make an unloaded single or double tip in the direction of the oarlock, so some attention must be paid when placing the boat in the water. Again - if this proves annoying to people, we'll experiment with a weight bar that could be added to the other oarlock. In the meantime, adding a second magnet to the opposite side can help alleviate some of the difference in weight.

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We typically see power numbers from the oarlock equate to 85% of ERG values but this varies slightly. In all three systems, WORK is calculated as FORCE over the LENGTH of the stroke. POWER is WORK over time. These are measured as the actual output of the athlete applied to the oar/handle and should be fairly equivalent. Work done by the athlete on the slide is not measured in either case, although it does affect the athlete/boat/oar system. Note that calories on the C2 erg are calculated differently as there is a "per stroke" addition for calories burned going up the slide standardized for a 175 pound male athlete.

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No current plans for a V2. Will support this with future software updates. There will undoubtedly be changes at some point - we've generally not stood still with our products - but this one has the smarts and connectivity to be updated for quite a long time.

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At a 2:30 you are definitely rowing hard enough that you will see slip and wash numbers that are reflective of your technique, and respond to changes in a relevant way. Your "wash" arc degrees below 100N are likely to be greater than a tall heavyweight sculler's, but reducing the value will indicate a more effective finish.

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That is actually the beauty of these values vs. speed, particularly where wind is concerned, or where you are using GPS speed on moving water: they are measuring the work YOU are doing in the boat to move the boat through the water. So, while your GPS speed may change with current, or your water speed may change with wind, work and power are accurate measures of your output and will be consistent indicators of your effort and effectiveness. (Slip and wash will be revealing indicators of how your technique changes with headwind and tailwind.)

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Users need to download the latest revision of the LiNK applications in order to export the Oarlock data. If you are just getting summary data in the export file, you most likely have an older version of the LiNK application. You can get the latest version of the NK LiNK Application here.

Learn More about LiNKGet the LiNK Now!
LiNK for Windows
NK LiNK version 1.32 for Windows

LiNK for OSX
LiNK Version 1.32 for OS X

LiNK for iOS
version 1.0.13

LiNK for Android
Use the NK LiNK app to view your workout data on an iOS device. v 1.0.13

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The pitch is set at 4 degrees for all of our oarlock products. It is not possible to use differently pitched bushings with this oarlock due to the fact that the load cell is installed inside the sleeve of the oarlock. NK had to develop smaller, custom bushings that are not compatible with other manufacturer's bushings.

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