The Rope Eater by Ben Jones

When Brendan Kane accepts a stranger's offer of work-two years on a ship departing the following morning-the nature of the journey isn't divulged. It matters not, though, for Kane is directionless himself, having just witnessed the Civil War's horrors only to return North with nothing but the clothes on his back and as many dead soldiers' letters as he could carry in his pockets.
Aboard the mysterious Narthex, Kane meets a ramshackle crew that includes an eccentric doctor and a three-handed Muslim full of horrifying lore. Kane learns only that they're sailing for the Artic in search of gold or maybe whales. But when it turns out the Narthex's destination is a temperate paradise hidden amidst glaciers-a mythical place-Kane and his cohorts must struggle to survive not only the bleak Artic conditions, but the loosening grip on sanity of an egomaniacal captain and the data-obsessed doctor. With each second that passes, it seems increasingly unlikely any of them will get out alive.