At what point do you have to accept that your child is gone?

Eight months ago, Ricky and Robin Wright’s 19-year-old daughter Danielle set off on the trip of a lifetime.

She was part of a seven-person crew who would sail a 21-metre wooden boat from the west coast of New Zealand to Newcastle, on the east Coast of Australia.

Danielle, who travelled from the US state of Louisiana for the trip, set off on her adventure on May 29, 2013. But on day three of the trip, the boat (named the Nina) ran into a storm.

There were a few satellite aided messages that came through to New Zealand in the days after the boat ran into the storm. But the crew has not been seen or heard from since.

After initial effort to find the boat failed, New Zealand authorities officially called off the search more than one month later, on July 6. Maritime experts assume the 85-year-old yacht sank immediately without trace. Both the Rescue Coordination Centre New Zealand and the US State Department are convinced there is no evidence the boat is still afloat.

But Ricky and Robin Wright still haven’t given up hope that their daughter is alive.

In fact, in the past eight months, they’ve devoted their lives to finding their only child. The Wrights have spent almost $664,000 on private plane searches.

And Mr Wright is in the process of getting his pilot’s licence so that he can fly over coastal areas of Australia and look for signs of that his daughter is alive.

You see, the Wrights survive with the hope their little girl is still living on the boat somewhere on the Tasman Sea catching fish and drinking rain water to survive.

And if she’s not still on the boat, they’re hopeful that Danielle could be living in a deserted coastal area or on an island with her fellow crew mates, waiting to be rescued.

In an interview with News Corp today, Mr and Mrs Wright – who temporarily moved from their home in Louisiana to a home in NSW’s Port Macquarie – said they will not give up.

“We cannot assume the boat sank without evidence, and we think it’s highly likely that it did not,’’ Mrs Wright said. “We know there’s a chance the boat sank. There is a chance. But do you assume the worst and stop searching?’’

But, as pointed out in the News Corp piece, “the search has to end at some point”. So at what point do you give up?

You can only assume Kate and Gerry McCann, the British parents if missing girl Madeline McCann, have asked themselves the same question over and over again in the years since their daughter went missing from a Portuguese holiday resort.

Since 2007, the McCanns have not given up hope their their daughter, who would now be 10 years old, is alive. Even after Portuguese authorities closed the case in 2008, the McCanns continued the investigation by hiring private detectives. The case has since been reexamined by British and Portuguese authorities.

But their daughter still has not been found.

For Queenland’s Bruce and Denise Morcombe, whose 13-year-old son Daniel went missing in December 2003, a relentless search meant they found closure – but it just so happened that the result of the search was not the one they’re prayed for.

In 2009, the Morcombes called for a coronial inquest into their son’s disappearance. And in 2011, a man by the name of Brett Peter Cowan was charged with Daniel’s murder. Just over a week after Cowan’s arrest, Daniel’s remains were found in bushland near the Glasshouse Mountains.

Ricky and Robin Wright have created a page that’s dedicated to the search for their daughter and her crew mates. It’s called ‘Bringing Home the Niña and Her Crew’ and it’s used as a tool to fundraise for their search.

A few weeks ago, Robin updated the Facebook page writing:

Ricky and I are wrapping up our visit to Australia and New Zealand in the next 2 weeks. It’s hard to even think about coming home without Danielle, but we’ve done everything we know to do to search for Nina and 7 very special people.

We know they can survive whatever the Tasman throws at them with God’s hand of protection covering them. Please keep all the family members and the crew in your thoughts and prayers as we continue to wait for our loved ones to resurface.

You can only assume that the recent story of a man who washed up on reef in the Pacific after 16 months adrift would have given more hope to the Wrights – just as the story of Jaycee Lee Duggard, who was found alive 18 years after she disappeared, probably gave hope to to the parents of Madeline McCann.

As spectators, it’s easy to make judgements about what the families in these situations should and should not do; we can say that the search area is too great and the resources too finite

But if you were those parents – if that was your daughter who was missing – wouldn’t you do the same? Wouldn’t you hold onto every possibility (no matter how absurd it may sound to others) that your child is alive?

I’m not a parent, but I know that I would.