Kerry Hamill was a great letter-writer, so his family knew something was wrong when his carefully penned correspondence stopped in 1978.
The young New Zealander accidentally sailed into Cambodian waters and was then captured, tortured and killed by the Khmer Rouge at the S-21 prison in Phnom Penh, where thousands died.
His brother Rob Hamill and his family now want to retrace Kerry's journey, as a way to heal and raise awareness about the plight of at least 2 million Cambodians killed under the regime.
"I'm connecting with my brother in many different ways. This is one of the ways. Coming here to Darwin is really special.
"The loss of 2 to 3 million lives in that terrible time, in that beautiful country with beautiful people and culture, [this is] a small way of acknowledging their losses as well."
For the past four years, Rob, who has been a champion rower for New Zealand, his wife Rachel and two of their sons, Ivan and Declan, have been sailing around Australia and the world.
The trip from Darwin to Cambodia will be the final leg of their journey.
Kerry had been in Darwin during the rebuilding period after Cyclone Tracy in the 1970s and he purchased his yacht Foxy Lady there before setting off.
"I think it's going to be pretty emotional., I know I'm going to be pretty emotional," Rachel said.
"But I think it's something that [our sons] will get a lot out of. They'll learn a lot more.
Two other men on board the yacht also died. Canadian Stuart Glass was shot, and British teacher John Dewhirst was taken with Kerry.
They travelled to Indonesia, Malaysia and Thailand and had dropped Kerry's girlfriend off in Singapore.
The yacht was later blown off course.
"They took shelter behind an island called Koh Tang about 50 kilometres offshore, and on the other side of the island was a Khmer Rouge naval gun base," Rob said.
"They were attacked by a gun boat."
Rob said his family's upcoming trip would be a chance to share more of the story with his teenage sons and talk openly about grief, which was difficult for other family members in the 1970s.
"They talk about grief being passed through the generations and so I don't want to have any of my grief carried subliminally, I suppose," he said.
Rob and Rachel's sons also want to hear more about their uncle.
"We haven't really talked about it in the recent years," Ivan said.
"So it would be good to have a proper talk about it with dad, I know it's going to be definitely sad."
Rob travelled to Cambodia in 2009 to give a victim statement at the United Nations-backed trials prosecuting senior leaders of the Khmer Rouge regime.
He also told his story in a documentary film, Brother Number One.
Rob said he initially felt awkward about sharing his experience, given many Cambodians had lost their entire families.
"I was really concerned but it was actually seen [in Cambodia] as a way, that finally someone may understand," he said.
"Bridging that gap to tell the story outside their own devastation, to communicate that to the world.
"That plays some role in minimising these things happening again."
Rob said he also wanted to reach out to anyone who knew or has memories of Kerry before he sailed from Darwin.
