Truly a thriller, with vivid descriptions of the seas and weather in Antarctica. The author's background is prodigious and lends tremendous verisimilitude to his descriptions of the place and the privations experienced by the crew of this sailboat in extremely hostile conditions. The physical difficulties are so overwhelmingly horrible, that I found myself concluding that all of those involved must truly be crazy, and the character development and backstory development was not adequate to the task of explaining why the crew would subject themselves to this tortuous trip.
The captain and crew put themselves in harms way to "save the whales" by interfering with the phony research activity that allows the Japanese whaling fleet to violate international agreements and slaughter whales, and harms way includes not only the violent weather and seas, but also the murderous captain of one of the killer ships that is part of the whaling fleet, who has previously rammed a similar boat trying to interfere with the whaling slaughter, leading to the drowning of several of their crew.
Puzzling philosophical and moral conundrum in that the captain and crew of the sailboat are willing to risk their lives and the lives of their crewmates but only some of the crew are finally willing to take the lives of the whalers who have tried to kill them by ramming their sailboat. Finally all but one of the crew is killed in a continuing confrontation with a wounded sperm whale, in the process firing an explosive tipped projectile into the wounded sperm whale after the whale repeatedly rams their sailboat each time they use their auxiliary engines, which send out acoustic noise similar to the noise of the whalers' ships. In the effort to save the whales, the sailboaters have been willing to risk the lives of their companions, themselves, and the whalers, but in the final confrontation with the wounded sperm whale only one of their number sacrifices herself swimming to the whale in a vain attempt to pull out the harpoon and getting bitten in half for her trouble, while the remaining crew fights for their lives and kill the whale while losing all but one of their number, with no discussion of further sacrifice before striking the fatal blow to the whale. This endangered animal, possessor of the largest mammalian brain on the planet, does not seem to show gratitude for the sacrifices of the sailboat crew, members of the alien species that is exterminating is cetacean brethren and its own species, and so is killed for its ingratitude.