"But as the last whelmings intermixingly poured themselves over the sunken head of the Indian at the mainmast, leaving a few inches of the erect spar yet visible, together with long streaming yards of the flag, which calmly undulated, with ironical coincidings, over the destroying billows they almost touched;-at that instant, a red arm and a hammer hovered backwardly uplifted in the open air, in the act of nailing the flag faster and yet faster to the subsiding spar."
Musing: The last vision from the ship is of Tashtego, the Native American, at the mast. The flag is calm, even as everything else is destroyed. The red arm and the hammer perhaps indicate the futility of the Native Americans still trying to save the flag - the flag that signifies the country that is destroying them. The imagery is actually pretty clear - the nailing of a flag to a sinking ship by a dying tribe. That Melville saves this image to the end is pretty telling.