the ALPHA ....a few questions

> 10 years ago
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seanhogan
seanhogan
QLD
3424 posts
QLD, 3424 posts
20 Apr 2016 9:05am
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
lao shi
WA
1346 posts
WA, 1346 posts
20 Apr 2016 7:35am
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
sailquik
VIC
6171 posts
VIC, 6171 posts
20 Apr 2016 12:03pm
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
seanhogan
QLD
3424 posts
QLD, 3424 posts
21 Apr 2016 4:33pm
thanks guys !!!!
Stuthepirate
Stuthepirate
SA
3591 posts
SA, 3591 posts
21 Apr 2016 5:45pm
What happened here Sean!?
That's some pretty funky gybing there man.





decrepit
decrepit
WA
12873 posts
WA, 12873 posts
21 Apr 2016 4:34pm
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
powersloshin
NSW
1855 posts
NSW, 1855 posts
21 Apr 2016 6:44pm

that's the french jibe
seanhogan
seanhogan
QLD
3424 posts
QLD, 3424 posts
22 Apr 2016 5:24am
^ 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
decrepit
WA
12873 posts
WA, 12873 posts
22 Apr 2016 5:43pm
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.
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