In 1986, when Suzanne Heywood was 16, her father drove her to a tiny bach on the shore of Lake Rotoiti and left her there. She was to care for her younger brother while their parents took paying guests sailing around the Pacific. The family were from England and had recently sailed to New Zealand; they had been at sea since Suzanne was seven years old, when her father set upon replicating the journeys of Captain Cook, dragging wife and kids in his wake.

What was meant to be a few weeks in the cold bach turned into almost a year. Suzanne lived “on a cliff edge of fear”, trying to study—she was not allowed to go to school—and kiwifruit picking to keep them afloat. Sixteen!

Wavewalker was her family’s boat, her home, and now her memoir. She traces the odd marvel—whales, rainforest, beaches—but mostly she unpicks her parents. Her father schemes and blunders and repeatedly crashes the boat into reefs. Her mother seems to outright loathe her. “You’re being selfish again,” she sighs down the phone, when Suzanne expresses her loneliness. “I told your father you would be.”

At seven, Suzanne’s skull is fractured in a storm; on a remote island she endures seven operations to relieve the pressure, with no anaesthetic. But there are quieter hurts in this childhood at sea. Co-opted into cooking and cleaning, rather than the correspondence lessons she’s desperate to complete, Suzanne spends much of her time exhausted, ignored, and quite obviously traumatised. “The dampness, the closed wooden cabins,” she remembers. “Salt. Waves. Diesel. Dust. Boredom. Loneliness. Fear.”

The bach at Rotoiti, if nothing else, is solid ground—and Suzanne uses it to launch herself, into the University of Oxford and a normal life at last.