Forward it to info at gpsteamchallenge.com.au, and I'll have a look.

One thing I've noticed with alphas is that the entry speed (on a reach) is really important. You need to have a big sail up, and be screaming across the wind. The gybe isn't really the most critical part of your alpha number (I've found), ie if you're only doing 20 knots across the wind then there's no way you'll ever get an alpha above 20 knots.

red said...

Had a good sail today and had some good planning gybes and thought I might get a PB for Alpha but on downloading noticed really low speed and also realspeed tended to pick strange "turns" for my speed. I've cleaned the file (to the best of my ability) and was wondering if anyone can help?

did you stay within the 50meter proximity range?

I haven't had an Alpha session yet but figure the best Alphas will be done by broad reaching into a start mark to get maximum speed, then arcing a turn upwind using momentum to maintain as much speed as you can over around 200m as you create a curved track to windward. Progressively tighten the arc until you begin your gybe at the maximum possible gybe speed. Hopefully your gybe point will be about 50-100m upwind of your start mark. Exit the gybe wide and as fast as possible then bear away to get up to speed as quickly as possible. Then create a similar arc progressively turning upwind again to just make the proximity of your start mark.

So the ideal Alpha should look bent around upwind and then bent back, making the overall run look like a bent banana. Some of Andrew Daffs best runs look a bit like this and it makes sense to me (although it was done to follow the sand bank at the time). But I'll cover myself also by saying I haven't got any decent Alphas so this might be total crap...