Hi,

been asked a few questions by my team members and was struggling to answer.

The alpha :

1)what is it supposed to look like on the water ?
I came up with the drawing I found on seabreeze
(my french version of it)



2) Distance
then I got asked : 50 m minimum or maximum between A and B ?

3) and yesterday I recorded an alpha (the green one) that actually looks like one (on ka 72 & google earth)



Any explanations/ clues ? Thanks in advance

Sean

Diagram is good. Some may use an upwind kink before the turn to wash off speed.
Maximum 50m A to B.
Maximum total distance 500m.
Can cross over like your image and still finish within 50m A to B but will be slower as more upwind.

The proximity for the Alpha is a circle with a radius of 50m. You can meet that circle anywhere inside and the software will calculate the best average speed for your run to a maximum path distance of 500m. (It can be a far lesser distance, but that will naturally be slower).

RealSpeed and GPS-Results will show you the proximity circle on your tracks like this example from RealSpeed.

thanks guys !!!!

What happened here Sean!?
That's some pretty funky gybing there man.

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Stuthepirate said..
What happened here Sean!?
That's some pretty funky gybing there man.

Looks like the GPS lost it's skyview in the gybe, or the GPS has a min recording speed greater than the min gybe speed and there's a big hole in the data.
To avoid this sort of thing, set min speed to 1kt and wear the GPS high on the shoulder or on the head.

that's the french jibe

^ Love it

yes those two are funny.... I told the mate I was racing with that day that I had to wait so long for him in the jibe that I started drifting sideways....

Decrepit, I've got the min/maxspeed alarm set, but I'll have to check for the min speed (don't remember ever touching that function...)

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seanhogan said..
^ www.seabreeze.com.au/images/forums/icon_smile_big.gif' /> Love it

yes those two are funny.... I told the mate I was racing with that day that I had to wait so long for him in the jibe that I started drifting sideways....www.seabreeze.com.au/images/forums/icon_smile_clown.gif' />

Decrepit, I've got the min/maxspeed alarm set, but I'll have to check for the min speed (don't remember ever touching that function...)

On the GT31, there's two, one under "memory card" the other under "data logger", and of course they both affect their respective files. Because the memory card is so big it doesn't hurt to have that set to 0. conversely because the data logger is small, 1 or 2 is probably better.