This thing again. I think all the misunderstanding starts from this one person misinterpreting Homer's "wine-dark sea" to mean blue. No. It means on the deep black sea.
In my own interpretation, Homer refers to the colour of red wine as you can see in a black earthenware cup of the sort that was common in ancient Greece, or a bronze crater, both very dark, and actually not so different from the colour of seawater as seen from a boat offshore (not exactly black, but not really coloured either).