Under sunny skies, the Frankfurt am Main gently sways on the waves of the deep blue Mediterranean Sea. But this is not good weather for refugees; the waves are too high for the small wooden or inflatable boats they are forced to cross the sea on. Earlier this week, the Bundeswehr sent the Frankfurt, its largest ship, to the waters off the coast of Libya from the port of Cagliari in Sardinia. The vessel is taking part in the European Union's Operation Sophia.

Sophia is not a rescue mission. "The purpose of our operation is to curb illegal migration from North Africa to Europe," Commander Andreas Schmekel said. Still, more rescues have been made than arrests: 13,000 people have been plucked from the sea in the course of the operation so far, but only 68 alleged smugglers have been nabbed. According to media reports, there are an increasing number of refugees in Libya waiting for the right moment to make the dangerous crossing to Europe.

A year ago, more than 700 people drowned when their boat sank off the coast of the Italian island of Lampedusa. At the time, it was the worst boat tragedy in the Mediterranean. About 500 people drowned in a similar incident just this week, according to the UN's refugee agency.

The crew of the Frankfurt am Main are experienced in dealing with sinking ships filled with refugees. They say they saved more than 700 people in the Mediterranean Sea off of Libya's coast in early April.

Kristin, a paramedic, said she and her team were on duty nearly 36 hours straight. "Before, I could not imagine that over 500 people can fit in a single wooden boat," Kristin said. Normally stationed in northern Germany, Kristin came aboard to support the Frankfurt am Main's medical team in early April. The 31-year-old has worked with the Bundeswehr in Afghanistan, but she said the maritime operation had unique challenges.

"There is hardship in Afghanistan, too," Kristin said. "But these people have experienced much suffering and misery - and you can tell. And when you see people jumping off boats, it can be quite depressing. These people are damaged. In their eyes you can see the suffering they have experienced." Kristin has two wishes on this journey: no deaths and no children.

'Very unusual operation'

Until the first boats show up, the crew goes about its daily routine: Shooting exercises are carried out with a machine gun, and firefighters simulate their emergency duties by running across the deck in helmets and breathing apparatuses. On the front deck, a petty officer who identified himself as Jan checks the lights in the red and blue containers. This is the first stop for people who are brought out of the water and onto the boat. "This is a very unusual operation," Jan, the ship's 22-year-old electrical engineer, said as he screwed in a lightbulb. "A lot happens that you do not expect."

Beside him was a picture of a gun and a knife in a crossed out red circle, which means that weapons are prohibited. When people are brought onto the ship, they are searched, examined by a medical team and interviewed. Then they are given new clothes.

Jan was on board when the Frankfurt am Main pulled those 700 people out of the sea in a few hours. "This is a type of stress we are not really familiar with," he said. "When that many people come on board, everyone here is excited," he adds.

Accomplishing the operation's stated goal of fighting smugglers has proved more difficult than plucking people out of the water. "At first, the smugglers escorted the boats out of Libyan waters," Commander Schmekel said. "Then they realized that there were warships out there - that they were doing something. After that, they never left Libyan waters again." Ships deployed for Operation Sophia are not allowed to enter that zone.

What the crew can do is gather information by interviewing refugees pulled out of the water. No one on the Frankfurt am Main believes that the Mediterranean mission will tackle the issue. "No problem created on land can be solved at sea," Schmekel said.