Is this idiomatic Latin? I can't find an example anywhere of "iacere" being used with a dative like this.
The usual "in vos" would suggest "at you", I suppose, so perhaps that would not work in this context.
A quick google search found a phrase "constructam iaciunt ponto" by Suetonius.
There are a few such instances of "iacere" with the dative, but they are in the poets, who are of course not the best model for standard idiom, and they seem to mean the same as "in ...". In the one you mention, which actually comes from the poet Virgil, they have clearly cast this structure "into the sea", and not "to the sea" in the sense that you throw something "to someone".