I'm not sure about this one. I think I'd translate waves of the sea back into havsvågor or vågor på havet. This is an interesting question, I'll try to think some more about it. As Lundgren8 says, it could never be havets vågorna, definites can't be possessed by genitive nouns.
Isn’t this example just the fact that in English (like in Swedish) a possessive expressed with an s-genitive never takes a further determiner, while the corresponding of phrasing always does? E.g.:
my brother’s children —> the children of my brother
the sea’s waves —> the waves of the sea
Because it's "The waves of the sea", not "Waves of the seas" I think that would be "Havs vågor", but I'm not a native, so if I'm wrong, someone will come and correct me :P
Anyways, saying Oceans' means "of the oceans" (plural), and the sentence is "of the sea" (singular) (or ocean, I think the word in Swedish is the same, "hav")