Sailing robot Honey Badger that could sail itself around the world
by Adam Fisher on 19 Feb 2014
An Orange Pixel flickers on the horizon, sandwiched between the inky azure of the mid-Pacific and the robin’s-egg pale of the Hawaiian sky.
The Drone That Will Sail Itself Around the World Corey Arnold
Extracts from a major feature article on Wired on a sailing robot, a Drone called Honey Badger
Richard Jenkins is the first to see it—a sailing robot, which has been blowing our way for a month. We’re in a small motorboat seven miles out at sea, just north of Oahu’s windward shore. Dylan Owens gets the next good glimpse. 'I see the wing,' he exclaims, 'and the tail!'
Jenkins and Owens are the engineering duo behind Saildrone, which in the words of their website is 'a wind-powered autonomous surface vehicle.' On October 1, the 19-foot craft was set loose in the San Francisco Bay with a simple command lodged in its electronic brain: Sail to Hawaii. For 2,248 nautical miles the boat did the rest.
The path it chose happens to be identical to that of the annual Pacific Cup sailing race, and the fastest anyone has traversed this course is just over five days. The single-handed-sailing record is eight and a half days. As Jenkins and Owens look on, Saildrone is about to complete what might be called the first no-handed ocean sail: San Francisco to Hawaii in 34 days. It’s not quick, but then again there is no one aboard to complain.
The journey has included a storm with gale-force winds followed by two weeks of doldrums. During the tempest, Saildrone was reporting speeds of up to 16 miles per hour and angles as extreme as 75 degrees, meaning it was heeled over and surfing down the backside of breaking waves—waves with enough power to snap it in two had they caught the boat in the wrong position. The doldrums were equally worrisome: With no one aboard to scrub the bottom, algae, seaweed, and barnacles might have overtaken Saildrone, transforming it into just another piece of flotsam.
As the vessel sails into sight, I see that it’s a streamliner—a narrow hull stabilized by two outriggers, one on each side. Its 'sail' is a sail in name only; in reality it’s a 20-foot-high, solid carbon-fiber wing. Extending from the back of this wing, halfway up the mast, is a tail—just like an airplane’s. ('That’s a little trick that I stole from the Wright brothers,' Jenkins says.) Above the waterline the boat is painted safety orange and emblazoned with the words OCEAN RESEARCH IN PROGRESS in all caps. The hull is black with bottom paint, and near the bow is the name in a fancy serif: Honey Badger.
The Honey Badger is more than a sailboat and more than a robot, although it’s both of those things. The Pacific crossing is really a test of a new type of sail that automatically keeps itself pointed into the wind, like a weather vane. Adjusting a little tab on the back of the tail—a task handled by the Honey Badger’s autopilot—is enough to maintain the correct course and to angle the wing so it creates forward thrust. There’s no need to employ ropes, winches, or even sailors. The mechanism is so simple it might really be best regarded as a plug-and-play power source. Like a windmill, it converts a ubiquitous natural resource into usable energy.
Its potential goes far beyond record-setting jaunts to Hawaii. One obvious application is to mount the wing on a fleet of sensor-laden drones and send them sailing into the world’s oceans, where they could report on their findings. 'I want to get the data we need to show that global warming is real,' Jenkins says. To that end, they could monitor ocean acidification, a key barometer of climate change.
Drones could replace the world’s weather and tsunami buoys. The waters around oil platforms could be sniffed 24/7 for the first signs of a spill. Tagged sharks, whales, and other marine life could be followed and their locations patched into the international marine-traffic control system with a warning to stay away. Protected borders, coastlines, islands, and environmentally sensitive marine areas could be patrolled by drones programmed to photograph any interloping ships.
What’s more, Saildrone’s technology is so efficient it could potentially power vessels that today require a motor. Jenkins has developed a scaled-up version of his wingsail to propel passenger ferries that ply the waters of the San Francisco Bay. On windy days, the ferry motors would power down while the wings did most of the work. By the time you read this, the ferry wing will be flying from a test sled backed by two government agencies, sailing back and forth along commute routes. Jenkins is confident the test will prove that in only a few years, the cost of retrofitting the ferries will pay for itself in fuel savings.
As we draw closer, it becomes clear that the Honey Badger has made the journey unscathed, and the mood changes from worry to jubilation. 'She looks just like I left her!' Jenkins, the boat’s mop-headed designer, says with genuine surprise in his voice. Owens—who is responsible for Saildrone’s electronics—is similarly relieved. 'This makes it concrete,' he says. 'For the past month it’s just been an icon on a web page.'
On the way into the harbor with the Honey Badger in tow, the men share Budweisers and congratulations. 'I was hoping to find a castaway hugging the back or a tooth from a great white or at least some guano on the deck,' Jenkins says. 'But it’s Honey Badger,' he continues, his cherubic face twisting into the froggy expression that always proceeds a joke. Owens chimes in for the oft-repeated punch line, a quip from the viral video that gave the craft its name. 'Honey Badger don’t care,' and then, with feeling: 'Honey Badger don’t give a shit!'
Sailboats have sails. Aerodynamically speaking, a sail is a wing. But the angle of a sail relative to the air moving across it—the wind, in other words—is controlled and adjusted by means of ropes and pulleys. Tremendous force (and usually a winch) is needed to set a sail so that it cuts through the wind at the correct angle and creates the lift that moves the boat. And then the problem becomes keeping the sail at the correct angle. The boat may turn, which turns the sail with it. The boat may speed up, which changes the speed and direction of the wind passing over it. Or the wind may shift, changing speed and direction all on its own. In every case, the angle must be readjusted manually—that’s what is meant by trimming a sail.
A hard wing on a free-rotating mount is a much more difficult thing to engineer than a mast—a simple pole held up by guy wires—but the payoff is in the actual sailing. By severing all the ropes that run between the boat and the sail on a normal yacht, a lot of the complexity of sailing goes away. In a normal sailboat, every turn of the rudder turns the sail. Not so with a free-rotating wing, which by its very nature is always correctly angled into the wind. Furthermore, dialing in the amount of sideways lift generated by the wing—thrust, in other words—is a matter of adjusting the elevator-like tab on the back of the tail.
How Saildrone Works
The six technology secrets that float this autonomous, ocean-crossing boat.
1. The Wing
As wind passes over it, the wing produces thrust. That force is concentrated on its axis of rotation, preventing the wing from spinning wildly.
2. The Tail
A ¬little tab at the back of the tail can be set to the left or right, causing the wing to rotate a few degrees and maintain an efficient angle of attack.
3. The Counter-weight
Positioned at the end of a spar, it adjusts the wing’s equilibrium so its center of gravity is balanced, allowing it to rotate as needed.
4. The Rudder
While in theory it’s possible to operate Saildrone by using only the sail, it’s more efficient to use a rudder to point the boat where you want it to go.
5. The Autopilot
GPS provides speed data and location. That’s all Saildrone needs to know. Navigation instructions reach the autopilot via satellite.
6. The Keel
If Saildrone gets knocked over, it will right itself because of the keel’s weighting. Its steep angle sheds debris like kelp and lost fishing nets.
The morning after the Honey Badger arrives in Hawaii, it’s time to send her out again. The new mission is to spin the odometer past 7,939 nautical miles and thus rob another sailing drone, Liquid Robotics of its endurance record.
Barefoot on the dock of the Kaneohe Yacht Club, Jenkins opens his iPad and drops a few new waypoints into the Honey Badger’s brain—aiming it around the South Pole and toward the equatorial Pacific. If successful, it will be the first drone of any kind to 'circumcise the world,' as Jenkins gleefully puts it. It’s approximately 25,000 miles—10 times the distance to Hawaii—with no pit stops. What are the odds?
'It’s a long shot,' says Jenkins, who points out that Saildrone was designed to get to Hawaii, no more. 'We cut a lot of corners when we started,' Owens agrees, 'because we were paying for it out of our own pockets.' Hawaii was the milestone that Schmidt wanted. 'Every sailing journey that I’ve ever been on has been a near disaster,' says Jenkins, sipping his beer from the bottle. 'We’ll see.'
A month later Jenkins checks on the Honey Badger’s progress for the day. The odometer stands at 6,000 nautical miles, but something looks wrong. Digging into the data he realizes that the sensor that measures the rudder’s angle is sending random garbage to Saildrone’s brain. Salt water must have somehow infiltrated the connection. 'That was the last analog circuit on the boat prone to corrosion,' Jenkins says, cursing himself for not having upgraded it. 'The new version of the boat is all digital.'
Jenkins and Owens start sending commands to the drone and realize that all is not lost. Even without the rudder, the wing should be able to steer it back to port. 'It’s a long way from dead,' Jenkins says. Reviving the boat is a simple matter of swapping the old-style analog rudder encoder with the new-style digital encoder. The only catch is that they’ll have to go to Hawaii to do it.
Another trip to Hawaii? The crew greets the news with a chorus of clinking glasses: 'Honey Badger don’t care.' And then they raise their pints high for their traditional toast. 'Honey Badger don’t give a shit!'
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