gps-icesailing

Hello all, 

I'm completely new on that site !! 

 

Could you explain me some facts : 

 

What's Alpha Speed ?

Why there's differences between watch screen / application / Gps foiling app ? 

I have a Suunto 5 Do I need to make some adjustements on the watch to be more accurate ? and if yes, How I can proceed ?

Thanks a lot for your help !!

Aloha!

 

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