South Africa's Cape Town is in dire need of fresh water, and an ambitious marine-salvager has an unusual solution: kidnap an Antarctic iceberg, use tankers and tugboats to drag it to Cape Town, and use the meltwater to hydrate a thirsty city.

How feasible is such a plan? On one hand, a 125-million-ton iceberg could supply 20% of Cape Town's annual water demands. On the other, moving such a monstrous iceberg could be expensive and dangerous, especially if the berg unexpectedly flips over, cracks or collapses en route, glaciologists told Live Science.

"The issues are going to be how massive it is and the fact that it's going to start melting as they go along," said Ted Scambos, a senior research scientist at the Earth Science and Observation Center at the University of Colorado Boulder, who isn't involved with the iceberg heist. "There are ways for the iceberg to break once it does start to get warm that are difficult to control." [In Photos: Huge Icebergs Break Off Antarctica]

The concept of "pirating icebergs" isn't a new one. But one of the latest cold capers is being floated by Nicholas Sloane, a South African marine-salvager who has experience fighting off armed pirates, rescuing thousands of rockhopper penguins soaked in fuel from a shipwreck and helping to refloat the Costa Concordia, the Italian cruise ship that capsized off Tuscany and killed 32 passengers, according to a profile in Bloomberg Businessweek on Sloane and his plans to lasso an iceberg.

Sloane's latest project was inspired by the years' long drought desiccating the city of 4 million people. Cape Town households are currently restricted to 18.5 gallons (70 liters) of water a day, according to Bloomberg. To put that in context, the average American uses between 80 and 100 gallons (300 to 380 liters) of water daily, according to the U.S. Geological Survey.

To ease the water shortage, Sloane has proposed kidnapping a huge iceberg — one measuring 3,281 feet long, 1,640 feet wide and 820 feet deep (1,000 by 500 by 250 meters), he told Bloomberg. He's already amassed a team of glaciologists, oceanographers, engineers and financiers for the endeavor, called the Southern Ice Project, which has a price of $200 million.

If the Cape Town government foots the bill — which seems unlikely because other options, such as desalination, are less expensive, Scambos said — the crew would use satellite data to locate the best-size iceberg on course for Gough Island, located about 1,600 miles (2,570 kilometers) away from Cape Town, Bloomberg reported.

Sonar and radar scans would reveal any structural flaws. If the iceberg passes muster, two tugboats would trap it with a $25 million net of ropes made of Dyneema, a supermaterial that's buoyant and suited for low temperatures, friction and tension.

If netted successfully — no small feat given that winds reach 80 mph (128 km/h) with ensuing waves in this part of the world — the iceberg would be dragged by two supertankers each pulled by a tugboat. This bizarre procession of ice, supertankers and tugs would follow the currents to save on fuel, first using the eastward Antarctic Circumpolar Current and then jumping to the Benguela Current, which would deliver them to South Africa.

The entire trip would likely take 90 days, Sloane told Bloomberg. Given known melt rates, the iceberg would be at least 8% smaller by the time it reached its destination, he said. Then, the iceberg would sit in the cold Benguela Current offshore, where it would be moored and wrapped in a humongous geotextile skirt to protect the ice from the elements. Machines would then churn the berg into an ice slurry that could be shipped to shore on container ships and put into municipal reservoirs. [Antarctica: The Ice-Covered Bottom of the World (Photos)]

Price versus payoff

The challenge is daunting, but "I do think that they'll be able to move a large iceberg," Scambos said. That's because, in part, the ocean's currents are in their favor.

"If it could be made to work in any location, that path from the Antarctic Peninsula to Cape Town is probably one of the best ones," he said. "The other good one that really has a shot is Perth, Australia."

Still, the crew would need to take many precautions. For one, meltwater could pool on the top of the iceberg as it's being towed, which could cause the ice to fracture. "If they've read through the literature, they should probably cut some trenches and make drains to make sure water doesn't accumulate on the upper surface because that can cause problems," Scambos said.

Second, even though the currents will help them "go with the flow," getting onto the right currents will likely be difficult, especially with such a huge payload, he said. It's also unclear how the iceberg's trek through the salty sea will contaminate the frozen fresh water within the iceberg, and whether organisms such as algae will start growing on it during the journey.

But if successful, the prize is pristine polar water. "It's fantastically fresh and clean," Scambos said. "Most of the waters are from hundreds to thousands of years ago."

Because an undertaking like this has never been done before, it will likely take four or five missions before the entire process goes smoothly and in the most cost-efficient way, he said.

The Antarctic won't miss a few of its icebergs, Scambos added. "The Antarctic sheds billions and billions of tons of ice every year," he said. "The amount Cape Town might take is "a tiny fraction of the ice that's in the Southern Ocean."

The proposal has a few things going for it, said Matthias Huss, a glaciologist at the University of Fribourg in Switzerland who isn't involved with the Cape Town project. "The iceberg would release its meltwater anyway, so why not use it for drinking water supply?" Huss told Live Science in an email. "Also transporting the water in the form of a block of ice is likely more efficient than shipping liquid water."

The prohibitive cost likely means this won't be a long-term solution for Cape Town's water woes, said Tad Pfeffer, a glaciologist at the Institute of Arctic and Alpine Research at the University of Colorado Boulder, who isn't involved with the Southern Ice Project.

"However they do it, it's going to be really expensive," Pfeffer told Live Science. "They could probably do it for as long as they have money for it. Economically, it's probably not all that good an idea, except in dire emergency."

Originally published on Live Science.