It is considered one of the most dangerous sports in Australia, and yet more than 1 million people take part in rock fishing every year.

Isaac Heagney, who has a passion for fishing, spent his HSC year developing an invention that could help save the lives of rock fishers who end up in the water.

"Once it's completely underwater, it sends a message and then the GPS's coordinates are sent to a nominated phone number," he said.

Isaac said he looked at existing products like the EPIRB, a mandatory safety item designed to be taken on board boats.

"But they're just too big and bulky to take on the rocks, like having a bag, and you've got to manually set them off," he said.

"I took the idea of an EPIRB and made it automated.

"So if you hit your head on the rocks, say when you fell in and you're unconscious, it can still alert someone that you're in danger."

Isaac has won the national title of Rural Scientist of the Year. ( Supplied: St Columba Anglican School )

The former St Columba Anglican School student from south of Port Macquarie on the NSW mid-north coast said he "took the GPS components, joined them together and came up with different coding ways to make it all work".

Isaac won the national title of Rural Young Scientist for his emergency alert invention, which consists of two compartments housed in clear acrylic and is completely waterproof.

The invention works by sending a wi-fi signal between a transmitter and a receiver.

"One is worn on your hip. It's about the same size as a bait bucket on a belt or a strap around your waist," he said.

"It communicates or wirelessly talks to another component, which stays out of the water but can't be in your car. It's got to be within a certain distance, so in your bag, up on a higher point on the rocks."

In May, Isaac will have the chance to showcase his winning design at a science and engineering fair in the US. ( Supplied: St Columba Anglican School )

Keen rock fisherman

Isaac has been fishing with his dad since he was a kid. He loves chasing jewfish or mulloway off the rocks whenever he can.

He would nominate his dad to receive the message and raise the alarm.

"He'd be straight down there pretty quick and able to alert marine rescue or any other emergency service, like on the way there he could be doing it.

Isaac has been a rock fisher for many years. ( Supplied: Isaac Heagney )

"Dad's always worried about it [safety]. If I say to him, 'Look Dad, I'm just going out for a fish', he'd always be asking, 'Where are you going?'

"He'd look at the forecast, the swell, sus out where you're going and then I … [thought], 'There's got to be a better way to do this, to stay safer.'

"He's always like, 'You should wear a lifejacket', but I'm like, 'It's so uncomfortable'."

As part of Isaac's major work he interviewed experts at NSW Maritime and Marine Rescue, as well as a couple of mates who are rock fishermen.

"They were all pretty positive about it and said something needed to be done because it is so dangerous."

Initially Isaac thought about a watch and ordered the first few components.

"I looked at the complexity and the size of them, and just the complexity of how to make a watch, and yeah, [the idea] went out the window pretty quickly because it was going to be more like a half-arm watch, not a little wristwatch."

Isaac has tested his invention for his major design work but he hasn't used it since because it has a SIM card.

"Every time I do want to use it I have to recharge the SIM."

Tacking Point Lighthouse in Port Macquarie is a popular fishing spot. ( ABC Mid North Coast: Luisa Rubbo )

Making rock fishing safer

Janine Fitzpatrick lost her husband Simon Williams in a rock fishing accident in 2014.

She is impressed by the device and wishes it had been around back then.

"To have been alerted that he was in trouble as soon as he was washed off the rocks might have made a difference and saved me and our daughters years of grief."

Ms Fitzpatrick said her husband loved rock fishing and would go out almost every weekend.

"He said he was careful, but the ocean is unpredictable and there must have been a moment of inattention or a slip or something that saw him end up in the water.

"If he had been wearing a device that automatically sent a signal back to us that he was in trouble it would have been an added safety feature that could have helped to make the hobby a little less dangerous.

"It would be great if Isaac's prototype could be developed and made available to the public."

In the past 10 years in NSW there have been 84 rock fishing fatalities.

Across Australia there were 123 rock fishing deaths in the same 10-year period, with NSW making up 68 per cent of the total.

In 2017/18, there were 10 rock fishing deaths recorded nationally.

Surf Life Saving New South Wales CEO Steven Pearce said it was encouraging to see young people take up the challenge of inventing devices that could potentially make rock fishing safer.

"As surf lifesavers we welcome any innovation that could make this dangerous sport safer," he said.

"We certainly encourage Isaac and others working in the sphere to continue their research as saving lives is ultimately what we are all working to achieve."

"My name got called out and I was like, 'Holy moly, didn't expect that'," Isaac said. ( Supplied: St Columba Anglican School )

For his prototype, Isaac won $2,100 in prize money and an all-expenses paid trip to the International Science and Engineering Fair in Phoenix, Arizona in May where he will have the chance to showcase his invention.

Justin Munro, the technology and design coordinator at Isaac's former school, said when they entered the Science Teachers' Association of NSW's Young Scientist Awards they did not realise the reputation and enormity of the competition or the experiences that would be on offer, having won the award.

"Isaac will have the opportunity to present his design to some of the best scientists and engineers in the world," Mr Munro said.

"Isaac is a very humble young man and I wait anxiously to see where his HSC major work may take him."

Meantime, Isaac has always had his sights set on a career in carpentry and hopes to start an apprenticeship.

"That's where my interest is, so [I'm] going to love it and leave it [science and technology] there with school."