We are of the age where mankind is just discovering the vast information involving the oceans and the earth itself, leaving much to be discovered and understood. Before we draw any conclusions about what Noah knew or didn't know, all we can do is postulate.
Nothing meaningful can be said about The Flood without proving the first claim:
That god exists and can be demonstrated to be true.
(faith, visions, voices, or other personal claims, will NOT be considered as evidence . . . )
I may misunderstand you, but that seems to me like saying that we cannot say anything meaningful about the moon with out first proving that God exists. There are things we can say about the moon and there are things we can see about the Flood. If you are really interested, there is a movie showing in many theaters on February 23 that talks about this: "Is Genesis History?" Check out http://isgenesishistory.com for locations.