SpeedWatch, wireless wireless STW

That’s my goose-bumped knee and I’m rowing at 2.2 knots through the water, which is my true speed in terms of performance, as opposed to speed over ground (SOG), which would be my true speed in terms of getting somewhere.  The distinction relates to endless discussions about what true True Wind is, which depends, but more relevantly to that JDC SpeedWatch strapped to my thigh.  It would be a fairly unremarkable gadget if it was a GPS (showing SOG) but in fact it’s listening wirelessly to a tough little transmitter under the boat’s bow seat, which in turn is wirelessly collecting STW data from a tiny magnetized propeller mounted on the hull a few inches away…

I was a little dubious about this double wireless technology, especially when it showed almost a knot of speed with the propeller laid out dead still for photography (below).  But then I read in the manual that such anomalies are typical when the system is dormant, plus I saw apparently accurate, consistent, and responsive readings when the little prop was actually spinning.  This is pretty serious gear, especially for small boat racers, and has lots of features I haven’t mentioned, like a 4,000 hour Lithium battery in that gigando “watch” (which, if worn on your wrist to the skipper’s meeting, may itself unnerve your opponents).  The package includes three ways to mount the prop to your boat, but should also include an extra prop (for ninnies like me, who knock them off accidentally).  There are manuals and photos at JDC, some good dope at this outlet, and the U.S. distributor is Ocean Equipment.