Don't be fooled.
Achar would like you to believe that the flood story we have in Genesis is "schizophrenic." Indeed, he has dedicated four long posts (with a fifth one promised) to the proposition that "the Noach text that we have in the Torah is an amalgamation of two competing versions of the tale."
His evidence? Repetitions, and competing details. For example, one "version of the tale" says God wanted two of each kind of animal on the arc, the other says 14 were requested. One version says Noah sent a raven, the other said Noah sent a dove. One version tells us Noah brought a sacrifice, the other doesn't And there are many more, in this vein.
I can't answer all of the problems Achar says he found, but I can answer the few I mentioned above.
First, the bible frequently gives general information, before providing the details. In Hebrew we call this klal u'prot. A famous example is the first verse in Genesis: "In the beginning of God's creation of heaven and earth, the earth then was welter and waste and darkness over the deep and God's breath hovering over the waters." This is the klal, the general information. The prot, or the details of the creation follow.
It can be argued that the first command to Noah regarding the animals (take them two-by-two) is the klal; the prot (take the pure, or kosher, ones seven-by-seven) followed. In fact, the unbiased mind sees this in the verse: "Of all the pure animals, take seven pairs, man and his woman; and of the animals that are not pure, two, man and his woman."
What about the raven and the dove? For reasons known only to himself, Achar neglects to mention that this particular "schizophrenic" detail is present in the epic of Gilgamesh, a parallel flood story featuring a man named Utnapishtim who, together with "whatever I had of all the living beings" escapes a divine-sent flood.
At the end of Utnapishtim's flood, he acts just like schizophrenic Noah, sending out a dove then a swallow, and finally a raven, which didn'tt return.
Remember Achar's central claim: "The Noach text that we have in the Torah is an amalgamation of two competing versions of the tale." If this is true, why are the doves and the ravens, details Achar says belong to competing sources, present in one source, the epic of Gilgamesh?
This doesn't prove that the Torah is a divine revelation, or that Noah's flood was an event in history. It simply delivers a swift kick in the groin to the claim that our Flood story is an amalgamation of two competing versions of the tale.