The Wind Whales of Ishmael - a novel by Philip Jose Farmer. This is a SF sequel to Herman Melville's Moby Dick(!)

With no more noise than of a ghost gliding over the ocean, the seas disappeared. Night was replaced by day. The ship Rachel was falling. And Ishmael, the lone survivor of Ahab's Pequod and now of the Rachel, fell through the empty sea-space and landed in another world. Where he landed was a place on Earth, but not of his time. Here, without seas, was a place of mighty whalers: of harpooners who flew their boats more than sailed them; and whales who soared for the heights where the air was too thin for men, instead of diving for the deeps. Here, too, was the home of the Purple Beast of the stinging death, but here also was the key to mankind's future.