Sharks, menacing tides and poor water visibility are some of the dangers Jessica Evans' will face when she attempts to swim around Moreton Island later this month in a bid to draw attention to mental health issues.

Key points: The 100-kilometre journey around Moreton Island is like swimming three English Channels

The 100-kilometre journey around Moreton Island is like swimming three English Channels Jessica Evans is hoping to raise money for the Black Dog Institute

Jessica Evans is hoping to raise money for the Black Dog Institute Her only protection from sharks will be an electronic shield

The open water competitor said she believes she will become the first person to complete the 100-kilometre journey around the world's third largest sand island off the coast of South East Queensland.

In preparation, Evans has undertaken a brutal, non-stop and unforgiving training program.

But the 32-year-old is willing to suffer through the weekly torture sessions in a bid to honour her uncle, whose long, silent struggle with depression ended when he took his own life last year.

The Moreton Island wrecks are a popular dive site. ( Ausfish )

"Sadly, a few months ago we lost my uncle Barry," Evans said.

"He was having this fight with depression and none of us really knew how deep and how severe that was.

"He was the light of the room more often than not, and to have that taken away from you, I really think the family is struggling — everyone's looking for answers."

Evans said she searched for an explanation by researching mental health issues, which led her to the Black Dog Institute.

"I thought, 'I want to do something big and I want to do something that hasn't been done before to raise money for that charity'."

Evans has had to learn to lower both her stroke rate and her heart rate. ( Supplied: Scott Newman )

Evans will not be swimming in a shark cage.

Her only protection will be an electronic shark shield designed to keep them away.

Her support crew will also act as spotters from the boat and in kayaks, and several of her open water swimming buddies have promised to jump in the water during the swim.

Like three English Channels

Evans will tackle the swim in four stages, covering more than three times the distance of most people who have swum the English Channel.

The starting point is Cape Moreton, on the north coast of the island and from there she'll swim in an anti-clockwise direction.

"At the moment I'm training eight times a week," she said.

"I definitely like to enter an event and know that I am well prepared, so we swim eight times a week and then we gym three times a week.

"Generally, the swim on the weekend will be a four, or a six-hour open water swim down on the Gold Coast.

"There are nights when I come home and I'm exhausted, like we've spent five hours in the pool that day and I've gone to work, and we've done an hour in the gym."

Evans is swimming eight times a week in preparation. ( ABC News: Michael Rennie )

Coach David Proud said the gruelling training program was vital.

"You've got to be able to swim at a fairly low heart rate, but swim for a long, long amount of time," he said.

"In the pool, when you're training for the distance swims in the 1,500 metres, you're actually swimming at a pretty high heart rate.

"The biggest focus is we've been trying to swim with a lower stroke rate and swim with 30 to 32 strokes per minute.

"She's (Evans) been getting down to swimming one-hour-one-minute for her 5-kilometre swim at that 32 (stroke) rate and holding that lower heart rate, so we've seen a big shift in that over the last three or four months.

"It takes a really special athlete to be able to swim for six hours at a time without really stopping too much."

Three gym sessions a week come on top of her regular swim sessions. ( Supplied )

Evans took up open water swimming with her partner Scott Newman, who will assist in her epic adventure.

"Begrudgingly, I've been dragged into a few [swims]," Mr Newman said.

"I've done a couple of longer swims, but I haven't been able to keep up with Jess on any of them.

"It's a draining sport. She does a lot of kilometres every week, there's a lot of training that goes into it, a lot of preparation that goes into these kinds of events.

"It amazes me how fast she can do things and how easy it looks, but how long she can do that for is beyond amazing.

"I just can't even fathom being able to do that."

Evans says open water swimming is "a different kettle of fish". ( Supplied )

Evans said the benefits of open water swimming went beyond health and fitness.

"The open water is such an unknown," she said.

"You can have the wind going one way, the sweep going the other way, you face blue bottles and jellyfish and everyone's always afraid of sharks.

"Time you might do in the pool doesn't necessarily correlate to the open water — you're dealing with the wind and the sun in your eyes, it's just a different kettle of fish.

"In Australia, we have some of the best beaches, the best open water you can find in the world."

Evans plans to begin her Black Dog Lap around Moreton Island on February 27 and hopes to raise $10,000 for the Black Dog Institute.