If I remember right...Barrage is on the main road out of Argassi towards Zakyhtnos town and is on the left had side somewhere...
An old and good friend of mine owns this cocktail bar. It has a friendly atmosphere and I thoroughly reccomend you go for at least one drink and to say hello to Yannis!...from the centre of Tsillivi and where the road forks up hill to the left and right to the beach...take the road to the left and keep going until you see it on a corner on your right (approx 5-10 min walk depending on pace!)...
You might want to venture over to the other side of the beach...I know it's a fair walk, but if you're after jetskis, then you might want to try the Jetski club owned by Nikos (near the Mango Beach Bar)...You can try and negotiate or tell him he was reccomended by me!...he'll know the name...
Don't know if Nikos has expanded this year, but prevous years he has had jetbikes only. Very friendly and won't let you go out without your life-jacket! Not sure on this years pricing, but you can but ask him!...
Forgot to tell you that Speed Club is located on the right side of Tsilivi beach (close to Mango Beach Bar.