NK Empower wireless oarlock rowing power meter review

After announcing they were working on a power meter last year, NK have now released their empower oarlock onto the market bringing a power meter that promises to be accurate, easy to use and – most important of all – affordable. I have been using mine for the last few weeks and so feel it is a good time to outline my thoughts – both the positive and the negative and also some thoughts of where I hope to see NK go with the product over the next few months and years.

If you’ve bought anthing from NK recently then the packaging will probably be familiar to you with their simple but effective plastic bag holder – saves having to break out the scissors!

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Inside the bag we have the empower gate itself, the magnetic plate (for measuring catch and finish angles), plastic inserts to help the gate fit snugly on your pin, the calibration tool, manual and in my pack some NK stickers.

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The NK gate itself is clearly larger than a standard gate but not overly so, the bulk itself is mostly in the back of the pin where the sensors and battery pack live.

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Generally this extra bulk at the back could be an issue for a bow rigger, and NK have a useful table that shows compabaility for most of the boat manufacturers out there – and yes, my single is a Fluideisgn which means the gate wouldnt fit….this isn’t a major issue however as NK have worked with Fluid to produce C-Cups that are larger than the standard ones, so luckily for all you fluid owners you also get your own special installation step.

Installing the gate

NK have a useful video and I have also noted my own installation findings.

Comparing the two C-Cups you can see the new one is considerably roomier

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One new C-cup installed, second to follow

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Now with the new C-cup as they are longer it will mess up your footplate position and also your span, so you have to re-adjust your span and also move your feet. Now the cup is around 3cm longer than the old ones

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So you can either move your rigger around that much to keep your boat trim the same, or you can move your feet one hole which is around 3 cm as shown.

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Now install the plastic washers into the gate and slot onto the pin with the magnetic plate below, make sure there are no washers between the gate and the magnetic plate.

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Now you need to make sure the plate is straight to make sure your angles are correct its recommended to get a long straight edge and line it up across both pins, making sure that it is at 90 degrees to the centreline of the boat.

Once done, tighten with the hex key. And with that, youre installed! Next you need to calibrate the gate

Pairing the Empower gate and the GPS

Again – more useful videos from NK

Firstly go into your speedcoach settings and setup,

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then go into “Accessories setup”

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“Oarlock Setup”

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Now you will see the following screen, currently blank as you are not paired.

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Press the enter button again and you will see the following screen and you select connection

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And now pair.

Now press the button on the side of the oarlock and it will begin to flash green slowly until it connects when you will see this on the screen and the oarlock will show a solid green.

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Note that you only have to do this pairing once, once they have been paired the first time then the speedcoach will remember and in future once you turn on the oarlock the speedcoach will automatically spot and pair with the oarlock without you needing to do anything.

A cool thing to note is on the pair page now where you move the gate you can see the angles change in realities like below

however the angles are not calibrated yet so that leads us to….

Calibrating the Empower gate

Even more NK Videos!

Going back to initial setup – in this setting pages it’s a good idea to clarify the blade lengths and inboard (essential for working out power as it has to know how much leverage you have on the oar to calculate your power) as standard its 288/88 but if you don’t have this then adjust, zero the force on the gate and then next zero the angles.

To do this, take the natty oarlock tool

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And fit it to the magnetic plate as shown making sure that A and B are at the top to begin with

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And select “zero angles” on the GPS

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The speedcoach will take you through the calibration

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Complete!

And now you’re getting accurate angles and are ready to boat

Note that the manual mentions you should occasionally calibrate both angles and force, this is pretty normal for power meters as outside conditions sometimes mean the values “drift” over time. A quick calibration can make sure that the numbers stay accurate.

In use the gate is impressive in its simplicity, as mentioned once you have calibrated it initially then it will automatically connect to that same speedcoach once it has been turned on, so it really is as simple as turning it on and away you go – if you are familiar with the speedcoach GPS then you will be immediately familiar with setting up the various screens on the speedcoach to show your data – except now you can also see

  • Catch Angle
  • Max Force Angle
  • Finish Angle
  • Force
  • Slip
  • Power
  • Wash
  • Average Power
  • Stroke Length
  • Work per Stroke
  • Effective Length
  • Avg Work per Stroke
  • Max Force

The NK GPS allows you to select up to 4 different screens in the classic view which showing any combination of the above which I find most useful during a workouts or you can set a detailed screen which lets you focus on a singe technical point like angles – better for technical outings

Why is training with a power meter important?

There are many advantages to using a power meter over a heart rate monitor or rowing on ‘feel’ – it’s for good reason that a power meter has become the most popular training tool in cycling after all!

The main advantage is that using a power meter takes out all the guess work involved in estimating how well you are rowing. With a power meter on your boat, there is a quantitative number that tells you exactly how much power you are putting out – or, in other words, how well (or badly) you are going – in short, a power meter doesn’t lie, whereas heart rate and boat speed can be affected by a number of external factors, such as fatigue, hydration, wind, stream and temperature. By using power you are seeing exactly how hard you are working and how well you are propelling the boat.

One thing to note – it’s not proposed that a power meter replaces a heart rate monitor – its best to use both since they are actually telling you different things. Power is the input of effort to move the boat and Heart rate is a relative figure which measures your body’s response to that effort. Using a heart rate monitor and power meter together will allow you to see how your body is responding to training.

Downloading your workout
Once you have finished your outing the workout will be recorded on the GPS – you can extract it from the GPS either by the android/ios app  or via windows or MacOSNote that at the time of writing if you export via a mobile app then the data file doesnt include the data from the empower gate (e.g. power, angles etc) – this is being worked on by NK at the moment and will hopefully be corrected soon. Exporting by Link means you end up with a .fit and a .csv file – the reason for two files is because of the challenges around support for rowing – currently all the main training sites have rowing as an “extra” sport and is not the main focus, so they don’t include the concept of rowing metrix like force curves and catch angles – to get around this the GPS produces two files

  • the .fit file which is formatted to be is fully compatible with all the main training log sites out there at the moment in the same way as .fit files are for cycling – so like cycling you get cadence, power, GPS route etc and all that information

strava page

  • the .csv file which a complete list of all rowing metrix in one place – not recognised by most sites out there but luckily one site is and that is rowsandall which has been configured to display the rowing specific metrix for your review

rowsandall curve

There are some points that are worth highlighting that are outlined in the FAQ on NK’s site

  • NK have used Bluetooth to connect the gate to the monitor – although this is a widely used connection method, it does have the drawback that it is only capable to create a 1:1 connection between the master and slave device – by that I mean that a gate can only broadcast to a single screen – if you think that through then it means with the current gate and GPS it is impossible for a coach and a rower to see data at the same time from a single gate, or even two people in a pair seeing each others power output at the same time.
  • The Empower gate cannot display a force curve either during the outing or from the data at the end of the workout – the closest you can see is a rough “curve” using the data points of the catch and finish angles and the peak force angle – NK does justify this however as they point out “Even after years of looking at and coaching with force curves, there is still no agreement on what makes a “good” curve” which is a solid argument
  • For scullers – Currently you can only use a single empower gate with a single monitor, you cannot connect two gates to a single monitor – i’m not aware of a technical reason why it wouldn’t be possible gates to a single screen over bluetooth but until this is activated this means the same drawbacks of a single side power meter in cycling apply to the empower gate and if you have a power imbalance (which most of us do) you may get incorrect power readings as your gate is doubling either your weaker or your stronger side to get the average power – again this is justified by NK as it cannot be that larger otherwise you wouldn’t go in a straight line! But again its worth paying attention to
  • Currently  I am seeing occasional drop outs when using the gate with a bluetooth heart rate belt which requires the NK GPS to be powered off and on again to reestablish connection and this has been confirmed by at least two other users – I have found that not connecting a HR belt to the GPS keeps the Empower connection stable  and I know NK are aware and are working on a fix
  • Wear could be an issue over time -the all in one build is excellent as a waterproof/lifeproof device, however over time I would see the plastic parts that come in contact with the blade would wear which would eventually mean it would need to be replaced – it will be interesting to see if NK could replace the plastics for you or if you need to buy a whole new gate?
  • Currently the GPS only allows 4 panes of data – personally I would like to be able to see some more since some points are better in context – for example catch angles, finish angles and overall angle are related but to see them all you would take up 3 panes – better to either have one pane scroll through the data points or have catch and finish on the same pane as the overall but smaller so it’s easier to see all in one
  • Price – the elephant in the room is price – at £600 for the empower gate and £389 for the GPS you are looking at nearly £1000 all in – on paper a lot of money but genuinely adding power to your training is the number 1 best way to improve your training efficiency and make sure that you are getting the most out of your workouts on the water as I have discussed before and how others have discussed before  – and remember that in cycling £1000 is common for a power meter so NK have actually done well to hit a lower price point with their empower gate despite the lower potential market – and compared to other power meters available today it is priced very well.

Conclusion

All in NK have produced a great piece of kit in the Empower oarlock, producing a power meter that’s easy to install, use and export the data for analysis – yes there are a few drawbacks currently, particularly the minor bugs mentioned above (although I have no doubts they will be fixed) – but NK has finally made an affordable power meter available to all,  and in my mind is the first thing that someone should buy if they are looking for something to help them reach their maximum potential.

 

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About stelph82

I am a rower who is a lot of a technology geek as well!
This entry was posted in Biomechanics, Gadgets, Rowing software, Rowing Telemetry. Bookmark the permalink.

3 Responses to NK Empower wireless oarlock rowing power meter review

  1. Somehow I just saw this post, even though you published it already in February. Great review, and thanks for the link.

    • stelph82 says:

      No it was an error on my/wordpress side – for some reason it published back when I started writing the review rather than when I published today 🙄

  2. Pingback: Rowe.rs workshop – why use biomechanics | rowingmusings

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