What do we learn from "b'Kol Todah Ezbechah Lach"?
Radak: I will thank You amidst a congregation.
Malbim: I will offer a Korban Todah and thank You for Your Chesed. One of the four groups who must offer a Todah are those who embarked on the sea.
Why does he add "Asher Nadarti Ashalemah"?
Radak: I will offer a Todah to You, like I vowed.
Malbim: I will go to Ninveh, like I vowed.
What is the meaning of "Yeshu'asah la'Shem"?
Rashi: My vows of Shelamim and Todah I will pay for the salvations, which are to Hashem. "Yeshu'asah" is like li'Yshu'asah. Also "Kumah Ezrasah Lanu" (Tehilim 44:27) is like l'Ezra Shelanu 1 .
Radak: I say that salvation is only to Hashem ? He saved me via a great wonder.
Malbim: Initially I feared that evil will come to Yisrael via Melech Ashur ? that is why I refused to go. I will hope to Hashem to save Yisrael from all their afflictions!
We find that the suffix Hei can be in place of the prefix Lamed. This is not only for going to a place (e.g. Mitzraimah), rather, also when it means 'for'. (PF)