Forums > Windsurfing   Gps and Speed talk

the ALPHA ....a few questions

Reply
Created by seanhogan > 9 months ago, 20 Apr 2016
seanhogan
2811 posts
20 Apr 2016 7:05AM
Thumbs Up

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

lao shi
WA, 1171 posts
20 Apr 2016 7:35AM
Thumbs Up

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.

sailquik
VIC, 3938 posts
20 Apr 2016 12:03PM
Thumbs Up

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.


seanhogan
2811 posts
21 Apr 2016 2:33PM
Thumbs Up

thanks guys !!!!

Stuthepirate
WA, 3323 posts
21 Apr 2016 4:15PM
Thumbs Up

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





decrepit
WA, 8347 posts
21 Apr 2016 4:34PM
Thumbs Up

Select to expand quote
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.

powersloshin
NSW, 903 posts
21 Apr 2016 6:44PM
Thumbs Up


that's the french jibe

seanhogan
2811 posts
22 Apr 2016 3:24AM
Thumbs Up

^ 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...)

decrepit
WA, 8347 posts
22 Apr 2016 5:43PM
Thumbs Up

Select to expand quote
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.



Subscribe
Reply

Forums > Windsurfing   Gps and Speed talk


"the ALPHA ....a few questions" started by seanhogan