Waterramp swallow tail skis? Followus tv ep 10

[I_Am_Mod]

I was just watching ep10 of the Followus.tv episodes from xavier bertoni and kevin rolland,
http://www.skipass.com/news/52646-followus-tv-ep10-waterjump-wake-mo.html

Followus.tv Ep10 glacier, waterjump, wakeboard, moto

(4:11 , 4:20, 4:47, etc....)
you can see that they have a ridiculous swallow tail mod on one of their water ramp skis, is this a functional mod to decrease surface impact, increase speed ?or is it just a beater experimental ski that they now used on the waterramps ?
i'm quite intrigued and would like to know what it is/could be ...

 

[I_Am_Mod]

better size:

 

[Myfirstname.]

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[I_Am_Mod]

*what it's for .....