Under Pressure - David G S Greene

This fiction book is based on my memory of a real Scientific American article of an experiment in which a dog is kept alive underwater, breathing water, nearly freezing, and under extreme pressure. Herein, a scientist is thrown into the North Atlantic, weighted with anchors, to discover the paradise dedicated to Odin, populated by his sacrifices. Sunken in that same watery depths, a slave cargo marches thousands of miles, surfacing at last to take care of a magnificent breed of sheep. A U-boat crew..