Velocitek

First impressions are that it certainly does what it says on the box. The large (35mm) display gives a choice of speed over the ground in knots, or vmg (velocity made good, taking into account both speed and angle) towards or away from the wind.

We all know that somewhere in between reaching around at high speed, covering lots of distance but making little progress, and sailing dead downwind, straight at the mark but very slowly, there is an ideal compromise for every wind strength.

It's straightforward enough to set the unit up for vmg: sail close to a mark on the water and press the buttons to input a leeward position, then sail to a point directly upwind of the mark, at least 75m away, to input this point. The unit now stores the wind direction.

With display set to vmg, its particularly interesting to experiment with downwind tacking angles. Obviously, on a beam reach, the vmg is zero: you'll never get to the leeward mark! But slowly bear off toward a run and you will see the vmg steadily increase to a maximum, then decrease again when the more direct sailing angle is offset by much lower speed through the water.

Once sailing close to optimum angle, it's particularly interesting to see how a small increase in pressure affects the ideal sailing angle: bear away too much and you see the vmg start to come down again. I don't think you'd ever want to use this in a race to directly steer by as you might in a big boat with full instrumentation, but in training it would be a great way to improve confidence in determining just what is the best offwind angle for each condition.

In particular, with an asymmetric kite, the trimmer could use the unit to quickly get a good feel for just how much pressure he should expect to feel in the sheet for each wind strength, and transmit this info through to the helmsman.

Obviously a wind shift will affect the vmg calculation, but we found that so long as the shifts were less than 10 degrees, the information on a long leg was definitely valid.

Equally fascinating is the device’s ability to store up to 10 hours of detailed data for download onto a PC. Though the software download was not particularly user friendly (especially if like us you are a Mac user!) the results are definitely worthwhile. Once the software was onboard, it was a straightforward job to convert the racetrack trace to a Google earth image file. On screen you can zoom in to get as much detail as you require, here we have left on screen the entire racetrack, including pre start and sail back to the yacht club. Its pretty clear that the wind shifts were the main tactical priority: look how the wind swung progressively to the left on the second beat, turning the starboard lay line into a beat in the last 200 yards. This level of detail is enough to check out a venue for permanent wind bends; establish the precise course position for tidal information, and provide a record of the decisions made around the course, therefore significantly increasing strategic intelligence.

At the next level, using free gps action replay software, you can run through your track around the course:

You can re-run your race, at any speed desired, with options to pause, speed up, slow down, zoom in, and read off speed, direction and vmg at any point in time. With more than one boat and unit you could follow more tracks simultaneously and compare performance.

The possibilities are endless, but we feel the most significant facilities are to refine downwind sailing techniques, and to review tactical choices and increase venue awareness.