1)
What is "Yagati"?
1.
Radak: One who is drowning, he screams for help.
2)
What is the meaning of "Nichar"?
1.
Rashi: It dried. This is like "Charah Mini Chorev" (Iyov 30:30).
3)
Why does it say "Kalu Einai"?
1.
Rashi: Every protracted hope is called Kilyon Einayim, e.g. "[v'Einecha