On Sunday, January 9, 1921, the watch stopped forever at 5.20pm, marking one of Warrnambool's darkest days.

Its owner, Norman Borthwick, was lucky to survive, but for 10 fellow passengers enjoying what should have been a leisurely cruise aboard the Nestor motor launch on a glorious summer afternoon, time was up. On Saturday, their families will mark the centenary of the ill-fated pleasure cruise that turned to tragedy, going down in history as the state's worst ferry disaster.

The pocket watch that Mr Borthwick was wearing when he and his wife and two children were thrown into the muddy Hopkins River that afternoon, is among the few tangible mementos to survive the tragedy and forms part of the Warrnambool and District Historical Society collection.

The Borthwicks, who had travelled from their Ecklin home with their children, seven-year-old Janet and six-year-old Jack, for an afternoon on the water, were among the survival stories of the day.

For others, there was no happy ending. Some families lost several loved ones, others were torn apart and children orphaned.

Hawkesdale resident Win Koenig never knew her grandfather, William Sharrock, but she is immensely proud of the man who died a hero saving others that day.

Constable Sharrock was a local policeman, off duty and on board the Nestor with his sister-in-law Eleanora Sharrock and her daughter Issabella.

At 48, he had known the pain of losing his wife Winifred four years earlier, leaving him to care for five children, the youngest just six weeks old.

One, Doris, was Win Koenig's mother. Constable Sharrock couldn't swim, but managed to save not only Eleanora and Issabella, but several other passengers before exhaustion and constricting clothing overtook him. His efforts earned him hero status, with three separate posthumous awards.

His five children, however, including Doris, were orphaned and raised by relatives. Mrs Koenig, named after her grandmother, said her mother kept her painful childhood memories to herself.

"Mum was a 'look forward' and 'get on with the present' kind of person. She didn't talk a lot about it," Mrs Koenig said. "She would say, don't look back, you can't change it."

From time to time, Mrs Koenig, 82 and her sister Gladys, 86, from Hamilton, still visit their grandfather's grave in the Warrnambool cemetery overlooking the river where he lost his life. The grave was unmarked until a headstone was erected in 1998 by Victoria Police.

"We do think of Grandpa and we are very proud of him. He was a very brave man," she said.

Now the sisters and their extended family want others to appreciate their grandfather's good deeds. They plan to donate several of his awards to the historical society collection.

Among them will be his Valour Badge, believed to be the first ever presented posthumously by Victoria Police and the replica brass bell from the William Sharrock police boat named in his honour in 2012.

The heroic policeman's name is listed on a stone monument behind Warrnambool's old court house acknowledging officers who lost their lives in the course of their duty.

Constable Sharrock's bravery was also recognised by the Royal Humane Society, along with that of fellow-passenger, Coode Island life saver Mary Le Marquand, 24. and 32-year-old Warrnambool boatman Leslie Arthur Tinker who were each awarded medals.

Tragically their efforts couldn't save everyone on board the Nestor that day.

Built, owned and captained by decorated Boer War hero Edward Geary, the 50-foot launch was near full capacity with about 80 passengers, including children, when she set off at 3pm that day from the Warrnambool rowing clubhouse headed for Jubilee Park.

Newspaper reports of the accident describe conditions as fine and warm, the water calm. Passengers were resplendent in their Sunday best, albeit heavy attire of the day.

The launch had been licensed for a couple of weeks and had travelled the same return course about 15 times previously without incident. But just a mile into the trip that Sunday, the Nestor began taking water.

The launch zig-zagged erratically. Mr Geary first tried to beach her on mud flats before throwing a rope to some lads in a boat, hoping to secure it to a fence post near the river.

But the rope slipped away and a gusty south-westerly drove her back into midstream. Despite desperate attempts to save her, the Nestor went under, throwing many into the water.

In the chaos that followed, terrified passengers were hauled from the water by rescue boats. Some were resuscitated on the river bank, others, weighed down by their clothing, could not be saved. Among them were little Evelyn Greenwood, just nine and her mother Ellen, 53, from Stawell.

It was also a double tragedy for the Walsh family with 53-year-old Jane Walsh from Ballarat and her niece, Katie Leahy, 29, from Penshurst, losing their lives. Both women were in Warrnambool visiting Jane's sister and Katie's aunt, Millie Main, married to local tobacconist William Main. Katie's mother Catherine was one of the four Walsh sisters.

Jane's great, great-nephew, Melbourne man Roger Walsh, said despite 45 minutes of resuscitation efforts to revive the women on the riverbank, neither could be saved.

Jane, described as a spinster, is buried in the Warrnambool cemetery, while Katie, an accomplished pianist, is buried with her parents at Boram Boram cemetery near Penshurst.

Mr Walsh, who has been researching his family history, uncovered a curious connection to the Nestor tragedy. Seventy-one years earlier in 1850, Jane's parents, Phillip Walsh and Ellen Kelly had sailed into Port Phillip bay from Ireland on the same day, January 9.

Jane and Katie were accompanied on the cruise that afternoon by their host, William Main, who survived, later giving evidence as one of 40 witnesses at a coronial inquest into the tragedy, much of it scathing of the captain's actions.

Questions emerged about the soundness of the Nestor's construction and the bilge pump was found to be not functioning properly.

Coroner D.W. O'Grady ultimately found Mr Geary guilty of culpable negligence and recklessness in the navigation of the launch and not taking all necessary steps for the safety of the lives of the passengers.

He was committed to stand trial for manslaughter the following month in the Criminal Court at Warrnambool.

In a shock announcement two months later that April, the Crown withdrew all charges against Mr Geary, the only explanation being that the manslaughter charge was unlikely to succeed.

For Warrnambool Family History Group president Ray Welsford, it's a twist in the tale as mysterious as Mr Geary himself. Despite his best investigative efforts, he could find no further explanation for the surprise turn of events.

Describing him as "an interesting fellow" Mr Welsford's research shows the Nestor skipper as something of an enigma.

A sergeant in the Boer War, Mr Geary was decorated for bravery under fire and hailed a hero on his return. In civilian life his occupations were listed variously as boatbuilder, fisherman, dentist and electrician. His death at the age of 84 in 1962 was recorded at Melbourne's Kew Hospi8tal for Mental Hygiene.

Perhaps the most surprising twist in the captain's colourful life was his marriage five years after the Nestor tragedy.

His bride was none other than Warrnambool girl Lily Oakley, a Nestor survivor. Mr Welsford will lead a Warrnambool cemetery walk at 2pm today visiting the graves of Nestor victims.

Cemetery walks will also be held on January 10, 13 and 26.