On a cold, rainy morning a few weeks ago, eight black inflatable rafts, loaded with migrants, bob in the waters off the northern shore of the Greek island of Lesbos.

One of them isn't moving.

Vassilis Hantzopoulos of the Hellenic Red Cross points to the horizon.

"This boat up there?" he says. "No engine. Failure of the engine. That's it. So they ask for help from the coast guard."

A Norwegian rescue boat with the European Union's border agency, Frontex, heads toward the distressed raft.

Hantzopoulos walks along the rocky shore with John Sims, a fire captain from Sahuarita, Ariz. He's teaching members of the Hellenic Red Cross how to use a remote-controlled rescue device called Emily — which stands for Emergency Integrated Lifesaving Lanyard.

You might call Emily a buoy. You might call her a boat. She's about 4 feet long, weighs 25 pounds and looks like a cylinder wrapped in an orange-red life jacket.

Sims steers Emily in the water with a remote control. She speeds toward the migrant rafts.

"I'll keep her about 20-30 meters behind [them]," he says. "She rides (waves) really, really well. The only thing that affects her sometimes over a wave is a little bit of wind. In a high wind situation we would actually fill the hull with some water to be able to weight her down some so, so, she wouldn't fly so bad off the top of the waves."

The raft nears the shore, Emily close behind. If someone falls into the water, he or she could just hug the device, Sims says.

"And it gives enough time for a lifeguard to then get suited up and get out to them," he says.

Up to eight people can hug Emily at once.

The raft arrives on shore. Hellenic Red Cross volunteers cover shivering Afghan migrants in Mylar blankets. Emily wasn't needed in this rescue. But Sims says she was standing by just in case.

"Emily is perfect as a floating life buoy or floating life jacket," he says. "If anybody has a problem — they're hypothermic, they're sick, there's a problem with the boat and they happen to fall overboard, Emily can be on site within seconds, and they can grab right on."

Emily was invented by Tony Mulligan, CEO of Hydronalix, an Arizona-based maritime robotics company. He says he designed the devices to be practically indestructible.

"They're made out of Kevlar and aircraft-grade composites," he says. "They can handle a 30-foot wave. They can be thrown off a helicopter or off of bridges."

Emily is powered by a jet engine system that's "basically a miniature version of a Jet Ski," Mulligan explains. It's powered by a 22-volt lithium battery similar to a laptop battery.

"A three-kilowatt electric motor drives the jet pump," he says. "The pump nozzles exit the back of the boat, shooting water jet stream to propel Emily."

Mulligan and his team made the first Emily in 2010. The first version was built to respond quickly in surf zones to assist swimmers caught up in rip currents. The first rescue involved a father and son caught in rough surf of the coast of Oregon.

"The helicopter wasn't going to be able to get there for an hour," he says. "The water's 50 degrees. And it was too rough to put swimmers in. And (Emily) ran out with a line. They grabbed on and (rescuers) pulled them back."

Mulligan has sent 260 Emilys to first responders around the world.

"We've been told that she's done a lot of cool things in Mongolia and Kazakhstan during floods ... and in Indonesia for tsunami response," he says.

Emily costs about $14,000, excluding taxes, shipping and import costs. Mulligan donated two to Greece and another two to Turkey to help with the rescue of refugees.

The 2016 version of Emily is equipped with two-way communication radios, a video camera with live feed to smart phones and lighting for night rescues. The motor is three times more powerful so it can fight strong currents. She travels up to 30 knots.

Mulligan works with Texas A&M University's Center for Robot-Assisted Search and Rescue. A team run by Robin Murphy is tackling the problem of how to make Emily autonomous.

They are devising a computer program that would allow a lifeguard to use coordinates to drive Emily near a cluster of people in need of help and to position itself in a way that allows the greatest number of people to grab on. This would free up the lifeguard to concentrate on people in immediate distress, such as an unconscious victim or a child.

"We're Roboticists Without Borders," Mulligan says. "The purpose is bringing technology to the first responders, then make it safer for them and make them able to do a better job."

This is more than a job for Mulligan. It's personal.

There's a logo on the back of Emily.

"You'll see a little rose on the logo," Mulligan says. "And there's the three initials, ERS, which stood for Emily Rose Shane."

So in addition to the official acronym, Mulligan named the boat Emily after his daughter's best friend, who was killed in a car accident.

She was 13.

"It was devastating for us and her family," he says. "She was a little girl who loved helping people."

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