Commentaire sur L’Exode 15:4

ירה בים Onkelos translates this by שדי בימא: HE HATH CAST IN THE SEA. The word שדי is an expression for “casting”. And thus, also, it says, (Exodus 19:13) או ירה יירה which Onkelos renders by או אשתדאה ישתדי “or he shall certainly be thrown down” where the ת is used in both these words in place of (as marking) the Ithpael form, so that in these Targum words the root is שדי‎.

מרכבות פרעה וחילו, after giving thanks to G’d for the destruction of Pharaoh and his horse, Moses refers to G’d’s fight against the army and his elite corps of officers which constituted the backbone of his army.

ירה בים, the verb is a variation of זרק or השליך, meaning: “he threw, flung with force.” It is used as such an alternate in Samuel II 11,24.