The point fritzo was making, is the bible can give pointers to where to look for things, and clues to what happened in the past. Sometimes it's the only record available, and even fanciful information based in fact can be useful.
		
		
	 
More than likely there was no single "Great Flood," that started all the different flood myths. Human settlements grew up around river basins (the Tigris, Euphrates, Nile, then Yangtze  in China, and many more). These rivers often flooded, killing many people and starting a myth. This is why flood myths show up in most religions.
	
		
	
	
		
		
			What's the difference between thinking there was an ark and there wasn't one?  Do you have evidence either way?  There WAS a large flood in the area due to a large natural dam break around what is now the Strait of Gibraltar, and nearly every culture in that area of the world has an ancient tale of a "flood" and how "someone saved a great deal by building a large boat."  While I don't think anyone seriously believes that every animal in the world was taken 2 by 2 onto the ark, it is reasonable to say that there may have been a farm village that saved all of it's animals in this method- hence the story.  Time and exaggeration probably made the legend to what it is today.
 
People with that spiteful "IF IT'S IN THE BIBLE IT'S HOGWASH" attitudes are just as annoying as the literal translation bible thumpers.  There's a lot of history in the bible, and it can be used as a tool to uncover our past.
		
		
	 
The thing is, the myths often get transmitted to other cultures. The Sumerian empire, which had a boat in its myth, predates every single other culture that has a big boat in its mythology. The Jewish flood myth is almost certainly just taken from the Sumerian myth. Not a different account, but later jewish scribes just writing down the myth that first was written down by sumerian scribes.
And just because there was a story about a boat first written down in Sumeria a couple thousand years ago doesn't mean there actually was a boat. More than likely, there was a really fucked up flood on the Tigris and the boat story was added later. That's what happens with these myths. They're mostly embellished.
Oh, and your idea about the gibralter flood is silly. That event occured 5.4 million years ago. 
http://www.sciencenews.org/view/gen...e_filled_Mediterranean_in_less_than_two_years 
Humans didn't even exist when it happened.