Testing two singles using the NK Empower Oarlock

Thought this might be of interest, this weekend I ran a comparison between two singles using the NK Empower gate and I thought people might find it useful to see the data collected in the test – to avoid any bias and to keep the focus on the data I have avoided naming the two brands used.

The format of my test was to do a loop 4k on the Henley Course doing a 1000m piece downstream at around rate 20 followed by a 1min piece at 32. I then switched into the second boat – I used the same set of blades in all tests and made sure both boats had the same rigger span, and that when switching the gate over kept it on the same side (bowside) and calibrated once I had switched.

The conditions were good with only a little stream, although it must be noted that a slight wind picked up for the pieces in boat 2 – the wind was blowing downstream making it a tailwind for the 1000m piece and headwind for the 1min

Boat 1 – 1000m piece

Average rate –  20.86spm

Power – 263.40 watts

Catch – 67 degrees

Finish – 46 degrees

Effective length – 98.7 degrees

Peak Force Angle – 22.11

Pace – 2:00

 

Boat 2 – 1000m

Average rate – 20.25

Power – 279.45

Catch – 74.38

Finish – 42.89

Effective length – 101.57

Peak Force Angle – 22.37

Pace – 2:01

 

Boat 1 – 1min piece

Average rate – 32.62

Power – 413

Catch – 66.60

Finish – 43.75

Effective Length – 96.48

Peak Force Angle – 30.81

Distance – 264m

 

Boat 2 – 1 min piece

Average rate – 33.31

Power – 453.88

Catch – 70.76

Finish – 40.68

Effective length – 97.02

Peak Force Angle – 30.19

Distance – 254m

 

Although I think the results were skewed a little by the wind (particularly in the 1min piece I think), I think in general it looks like Boat 1 has done better in the tests. Despite shorter drive lengths and lower average power it was still the faster in both the 1000m and 1min tests.

Interesting that despite significantly different catch and finish angles between the boats the peak force angle was the same when at the same rate?

 

Below are a couple of graphs from rowsandall comparing the data

bokeh_plot

 

bokeh_plot (2)

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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. Bookmark the permalink.

4 Responses to Testing two singles using the NK Empower Oarlock

  1. Tom: Great idea for a comparison. Any chance that you could upload the two sessions to rowsandall to do analytic comparisons? I’d be interested to understand if the catch angle difference is just a rigging or cal shift. I’d also be interested to look at things like the correlation of work per stroke and pace to see if there is a difference.

    • stelph82 says:

      Yup already loaded onto rowsandall – which graphs would you like to see? angles seem to be a rigging thing as they are faily constant through the pieces – ive uploaded the work per stroke vs pace, would appreciate your thoughts!

      • It seems curious that the peak force angle is the same even though the catch and finish angles differ. Although maybe that is more specifically related to the geometry of the oars and the boat instead of the oars and the rower? As for things to compare, I think when you are doing side to side comparisons of equipment, the thing that I would be most interested in would be pace vs power. That would essentially be the efficiency of the boat (plus all the errors you get from measuring speed). It would also be interesting to try to look at power vs stroke rate for the two trials to see if there are differences

      • stelph82 says:

        Agree, the peak angle is unusal although as you say it could be linked to the geometry of the blades/pin since 0 is always straight between the pin so perhaps that position in the stroke is always where I get the most leverage despite the couple of degrees difference in catch/finish – its a shame you don’t get the full curve with the NK to be able to compare in detail

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