In September 1940, the British ship SS City of Benares was sunk by a German U-boat in the mid-Atlantic. Among the passengers were 90 children, nicknamed "seavacuees," whose parents had made the painful decision to send them to Canada, New Zealand, Australia and South Africa — where they believed they would be safe from the near-constant bombings of Britain by the Nazis.

While much has been written about the children who were evacuated from cities to the British countryside, less is known about the program that sent children overseas.

Hazel Gaynor, who has written six other historical fiction novels centered on events that took place during World War II and whose "The Lighthouse Keeper's Daughter" was a bestseller, now uses the fate of the City of Benares as inspiration for "The Last Lifeboat." Its story closely mirrors the sinking of that ship, which Gaynor calls the Carlisle.

Gaynor's primary characters are Alice King, a young librarian who volunteers to escort children heading to Canada aboard the SS Carlisle, and Lily Nichols, a war widow whose children, Georgie and Arthur, are aboard the ship.

From the moment the torpedo strikes the Carlisle and it begins to sink, "The Last Lifeboat" morphs into a gut-wrenchingly suspenseful story. Many of the ship's lifeboats, filled with passengers, tip before they can be launched, spilling children and adults into the icy waters. Some that are successfully launched capsize amid fierce winds and waves.

Only seven of 90 children appear to have survived the catastrophe, but as readers soon learn, the lifeboats have been undercounted. At least one is still afloat, carrying six more children — including Arthur Nichols and his protector, Alice.

Gaynor's strength as a writer is in her vivid portrayal of the struggling adults and children aboard the forgotten lifeboat. Her cinematic descriptions evoke strong emotions in readers. She deftly describes the food and water shortages, the passengers' wet clothing, the frigid air, the fierce waves and the terrified children's chapped and water-logged skin.

There are so many heroes in this story. In one scene, a man leaves the lifeboat, sacrificing his life so there will be more food and water for the children. Before he goes overboard he tells Alice: "Get the children back to their mothers whatever it takes." And then there is Arthur's mother, who determines that the lifeboat carrying her son might still be afloat a week after the torpedoing and persuades the government to resume its search.

Novels inspired by wartime tragedies and heroics fill miles of bookshelves, but you won't easily forget what happens on the last lifeboat.

Carol Memmott is a writer in Austin, Texas.

The Last Lifeboat

By: Hazel Gaynor.

Publisher: Berkley, 370 pages, $17.