The sinking of the Marquette was one of World War I's most epic sea tragedies.
A naval court of inquiry found no one was at fault, but it raised suspicions of sabotage, and queries about why nurses had been transported on an unmarked, grey ship, and not a hospital ship, protected under the Hague Convention.
Isabel Clark was born in 1885 to early Scottish settlers who won a 122-acre (49ha) section at Ardgowan outside Oamaru in a Government ballot to divide land. The youngest of six children, she studied at Waitaki Girls' High School where she "displayed more than ordinary ability and industry".
She followed her beloved sister Elsie into the nursing profession by training at Waimate and Oamaru hospitals, passing in 1912. She worked at private hospitals in Dunedin and Auckland before war broke out.
The short, slender woman, who was a stickler for accuracy and efficiency, quickly joined the Army Nursing Service. She formed a contingent of 100 nurses that left Wellington on the hospital ship Maheno on July 11, 1915.
On arrival at Port Said, Egypt, she worked at a local hospital before setting sail from Alexandria Harbour on the Marquette, bound for Salonica, Greece, on October 19.
Five days later, around 9.15am on a cool, blustery October 23 morning in the Aegean Sea, some nurses were walking on the promenade deck where there was a terrific explosion.
The torpedo, fired from a German submarine, tore apart its starboard side and it began to list to port, before starting to sink by the bow.
A survivor wrote to the Clark family in March 1916 to inform them of their loved one's final moments.
Another nurse told of seeing Miss Clark and a friend - both laden by pantaloons, two petticoats, a starched grey dress with a long full skirt, long sleeves and a stiff collar and cuffs, a full length starched white apron, a red cape and a white veil - walking down the gangway "hand in hand".
"She saw them speak to one another and together they jumped into the sea."
Their bodies were never found.
One unnamed nurse told the Auckland Weekly News of the courage shown by her colleagues. "The nurses ... refused to go into the [life] boats until most of the soldiers were saved: they stayed on deck cheering them on until only a few men remained."
Miss Clark's final letter was to her sister Elsie, then living on a South Otago farm, and spoke of her excitement at the crossing to Greece.
But it also came with an eerie premonition: "I suppose we will run the risk of being torpedoed."
The 32 New Zealanders who died in the sinking are commemorated on the Mikra Memorial in Greece.
