SüdTeam Training Koblenz

On 29. Jan 2012 I was in Koblenz for some in-field testing of various new features and to record sample data from two JFA 8+ at different stroke frequencies. This is the first time I have used video synchronization on the water and the results are promising. Data has been recorded using an iPhone4 in the boat and an iPad2 captured HD video material in the motorboat. The acceleration graph is overlayed straight into the video, so there’s no post processing required on the user side. This is great for ad-hoc analysis because the video is directly available on the iPad Photo library and can be replayed using a slow motion video player such as VideoPix. And of course you can also download the Videos from the device using the USB Cable to your PC/Mac.

I have posted some of the results on the RowMotion YouTube channel:

Weather conditions weren’t perfect as you can see in the video, the wind was pretty rough and made it difficult to record without shaking to much. And it was freezing cold! Anyway, it wasn’t an issue for the ladies and we had a pretty good training session.

As you can see in the videos, even though the data connection is buffered data delivery over WiFi is still dropping data from times to times and/or not delivering in time. Part of the issue in this session was that I mounted the iPhone near the bow, whereas it would have reduced the distance to the WiFi Access point if mounted near the stern. Another mounting tip that I will apply the next time: I did place the iPhone below the water line. From a technical perspective this is absolutely sub-optimal since water is excellent at swallowing 2.4GHz WiFi signal. In the future I intend to maintain a best-practices section to share these experiences.

I did observe an interesting effect though when we went underway a bridge and signal stabilized all of a sudden (this is the piece with the SF30 recording). It seems the bridge did a good job reflecting the WiFi signal between the hull and motorboat.


  • Jon

    Good lesson, well exeiplnad, with good, friendly vocal presentation. Ratio triangles can also be quite useful for this introductory topic only. The equals ( = ) sign does not come out well with the computer graphics. I notice negative indices are not used at this stage, namely m/s^2 is used rather than ms^(-2). I guess that is also fine for an introduction. Seeing that you have had no responses so far, I’m hoping to have done you a favour by posting the first. Keep up the good work. Regards, Rick Swan.

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