It has been labelled the world's weirdest race, but unlike some of the watercraft built for the event, Darwin's Beer Can Regatta has managed to stand the test of time.

First run in 1974 as an event to clean up beer cans littering Darwin's streets, the race that involves boats made of drink cans has become an iconic event for the city.

The regatta attracts more than 15,000 people to Mindil Beach every year.

It has also sparked a small but passionate number of enthusiasts with in-depth knowledge in the craft of making boats out of cans.

Darwin resident Mick Keeley has been making the unique watercraft since the 1980s.

Beer can boat builder Mick Keeley stands next to a pile of cans. ( 105.7 ABC Darwin: Emma Masters )

"A few of us decided to build a boat, so we collected cans and sat around on Sunday afternoons and taped them together," Mr Keeley said.

"We built a boat, went down to the regatta and had a fantastic time, so we did it for a few years after that.

"Then you have kids so there's no time for doing it then, and now they're big enough I'm back doing it again."

Designing and building beer can boats has evolved into more than a passing hobby for Mr Keeley.

The entry for this year has taken over his expansive backyard, including purpose-built infrastructure he has developed to prepare the cans for maximum buoyancy.

"It's my secret weapon," he said.

"You've obviously got to seal them and everybody knows how to do it — they put the two open ends together and run tape around it.

"I've come up with a different method that seals them.

"It's the same thing with two open ends together, but it takes about half the time and half the expense and works really, really well."

Growing big ideas

Extravacanz: The largest boat ever entered in Darwin's Beer Can Regatta. ( William Nguyen Phuoc )

The avid beer can boat builder said his work as a fitter and turner has helped make his ideas a reality.

"The boats get bigger and better all the time," he said.

"A couple of years ago I built this monstrous great thing that had 30,000 cans — it was called Extravacanz.

"It was when the container recycling came in and I thought it might kill off the regatta so I'd see if I could do something rather radical.

"We had 87 people on the boat at one stage, so a lot of people will remember seeing that one."

Beer Can Regatta president Des Gellert said Extravacanz is one of the most memorable boats he has seen in the history of the event.

"It was a catamaran two-hull craft with a second floor and a water cannon," Mr Gellert said.

"It was pretty spectacular to see that coming around the point for the very first time.

Beer can boat builder Mick Keeley works on the paddle wheel for his entry in this year's regatta. ( 105.7 ABC Darwin: Emma Masters )

"Mick takes a great deal of pride in the boats he builds."

Mr Keeley plans to build a boat bigger than Extravacanz but has held back on this year's design.

"It's a steel frame, about 6,700 cans, a catamaran design again because they're stable, but the different thing with this one is I've designed a paddle-wheel system," he said.

"Two people sit on each hull and pedal away and the paddle wheel goes around and around the middle and hopefully we go forward."

Nevertheless, it is likely the boat will still be the biggest in this year's competition.

"We're expecting perhaps 12 to 14 boats this year, some of them will be around 5,000-can mark," Mr Gellert said.

"So it will be quite big boats compared with our usual 2,500-can boats."

From beer-swigging to family-friendly festival

The Beer Can Regatta has evolved over the years.

It is an all-day event that includes boat races alongside thong throwing and sandcastle competitions.

"There was a time when the event was a drinking festival," Mr Gellert said.

"You went there deliberately to get drunk and you were going to make a mess of yourself.

"Since the mid '90s we've been moving more toward a family-orientated event, like the old beach festivals from 15 to 20 years ago.

"We are not quite there yet, but we are working on it."

The founder of the event, Lutz Frankenfeld, is quick to dispel rumours the regatta began to clean up the mess after Cyclone Tracey devastated Darwin on Christmas Eve in 1974.

"The first regatta we ran was in June 1974, before the cyclone, and it was a huge success," Mr Frankenfeld told 105.7 ABC Darwin

"We had 63 entries and Mindil Beach was absolutely covered in people.

"It began because we were concerned about the amount of rubbish around.

"You could drive up from Katherine and find Darwin quite easily with all the cans along the road, so it was a matter of cleaning up the town and putting something together."

The 1974 poster for Darwin's first-ever Beer Can Regatta ( Northern Territory Archives Service )

The founder said the event grew quickly.

"We had up to 18 classes, including motor classes, by the '80s," Mr Frankenfeld said.

"In the end we had so much competition interstate with the boats that got faster and faster in the different classes and it just progressed into a world-class event.

"The Americans even wanted me to come over and organise a beer can regatta for the lay days during the America's Cup."

He explained there were also strict rules about how the boats were built.

"You had to build it from cans and cans alone," Mr Frankenfeld said.

"You had to put a bucket of water on it and it had to drain out, otherwise it wasn't legal.

"That's what it was all about and what they are doing these days is totally wrong."

But some of today's competitors are not as concerned about a relaxing of the rules.

"I don't care if someone goes down there with cans stuck to the side of a tinny," Mr Keeley said.

"People complain about it but to me it's somebody having a go.

"It's not about winning anything really, it's all about having a go and having a fun day."

Darwin Beer Can Regatta begins (1980s). ( Picture NT, Northern Territory Library )

The Battle of Mindil

Despite the changing face of the race that stops Darwin, there is a part of the regatta that remains a sure favourite among competitors and onlookers alike.

"The Battle of Mindil is my favourite event," Mr Keeley said.

"All the boats go out there and people throw flour bombs at each other and try to destroy other boats and carry on — it's all good fun."

The race organiser admits the Battle of Mindil is the time when anything goes.

"It's not a race so much as a treasure hunt," Mr Gellert said.

"The aim is to find the treasure and to get it back to the beach but if somebody finds the treasure then the other teams are allowed to take the treasure off them and get it back to me.

"This is where people go mad, throw water and flour bombs, try to up-end each other's boats — it all happens.

"It's certainly unique and it has been running for 42 years.

"It should go on everybody's bucket list to come along, at least once."