View Full Version : Re: validity of boat velocity measurements

Johan Tegin
11-30-2009, 10:17 PM
At KTH a system was developed within the scope of our MSc project
course a few years ago. The system was intented for some of our
students who also happen to be on the national team (if I recall
correctly) and is using a GPS for position and velocity. The system
can also measure the amplitude of the stroke, the motion of the seat
and the feet contact forces. It may be possible to manufacture more
such systems. I'm trying to find more information on this and you are
very welcome to contact me directly if you're interested in further

Best Regards,
Johan Tegin, PhD
Researcher, Mechatronics Lab, Machine Design, Royal Inst. of Tech.,
Stockholm, Sweden

> Vi mäter pos, hastighet med GPS. Vi mäter också årutslag,
> sätesrörelse samt kraft från fötter.

30 nov 2009 kl. 21.33 skrev Dat Phan:

> Lisa,
> I believe most auto magazines and auto manufacturers use VBox made by
> Racelogic for car performance data acquisition. Their devices log
> data at
> 5-100 hz.
> http://www.racelogic.co.uk/?show=VBOX
> http://www.racelogic.co.uk/?show=VBOX-Products-Data_Loggers
> http://www.vboxusa.com/products.php
> The VBOX II SX5 samples at 5hz and retails for £1600 (~$2600).
> Listing on
> vboxusa.com:
> The VBOX IISX is a powerful instrument used for measuring the speed
> and
>> position of a moving vehicle at 20Hz. It is based on a new
>> generation of
>> high performance satellite receivers, and will measure acceleration
>> figures,
>> braking distances, lap times, cornering forces and much more. Due
>> to the
>> small size and simple installation procedure, the VBOX is ideally
>> suited for
>> use in cars, bikes, off road vehicles and *boats*.
> Hope this helps.
> Dat Phan
> MS Student, Kinesiology
> San Francisco State University
> On Wed, Nov 18, 2009 at 10:32 PM, Lisa McDonnell
> wrote:
>> I'm interested in devices used to measure boat velocity (ie: sprint
>> kayak)
>> accurately... given flat-water conditions, little wind etc. It's
>> important
>> that we reach a high level of precision and interested in
>> calculated stroke
>> to stroke boat velocity (takes approx. 0.4 - 0.6 seconds for a
>> single sided
>> stroke) when determining performance variables.
>> I have considered impellers with a velocity sensor made by NK used
>> for
>> Rowing, but have also heard that there are high frequency GPS
>> systems that
>> exist and sample at 4 Hz? Can anyone suggest a product, or know the
>> approximate cost of such a GPS device? Or are there any other
>> devices that
>> can measure stroke to stroke boat velocity?
>> Thanks,
>> Lisa McDonnell
>> PhD Student
>> Institute of Sport and Recreation Research New Zealand
>> School of Sport and Recreation
>> AUT University
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