The freighter MV Stannis left the Libyan port of Bengasi several weeks ago, passed through the Straits of Gibraltar and then turned south. The freighter - not the most modern of vessels - has now set course for the port of Lagos in Nigeria.

On the bridge stands 46-year-old Captain Dirk Smith, scanning the horizon with his binoculars. The radio crackles into life. The Nigerian frigate Thunder is enquiring after Smith's ship and freight.

Smith replies that he has machinery and spare parts on board. He is lying, of course. MV Stannis is smuggling weapons.

In reality the ship isn't called MV Stannis, but Hamburg. It isn't an old freighter, but a modern German frigate. Dirk Smith's real name is Dirk Steffen and he is a German naval captain.

The Hamburg is playing the part of an arms smuggling vessel in a multinational naval exercise, "Obangame Express."

During these naval maneuvers off the West African coast, 20 countries are practicing anti-piracy and anti-smuggling operations. The focus is on acquiring familiarity with communications, chains of command, and how to board suspicious vessels.

They came in a speed boat

Thunder has just lowered a speed boat on to the water. Ten soldiers are on board. The boat circles "MV Stannis" once and approaches the ladder on the port side which has just been let down.

Two of the soldiers stay in the speed boat, the remaining eight scramble up the rope ladder as it sways back and forth, their automatic weapons at the ready.

Once on board, the soldiers, clad in black, cover the gangways and stairs and keep the ship's crew in check.

Cautiously, they make for the bridge where they encounter Captain Dirk Smith. The make-believe weapons smuggler confronts the soldiers telling them to leave his ship. "Turn around," they command .

As he refuses to obey, they force him to the ground and handcuff him.

Below deck, two Nigerian soldiers are insisting that two other walk-ons in this rehearsal for a naval operation hand over their papers. "Captain Smith" is brought below. A little later, a soldier appears on deck again - with another member of the ship's crew.

Cardboard boxes with photos of weapons

In the cargo hold, the Nigerian soldiers are hunting for the freight. They find cardboard boxes plastered with photographs of weapons.

Back on deck, blinking in the sunlight, they inform Smith his vessel will be heading for the port of Lagos under naval escort. The boarding team from the speed boat will be staying on board the "MV Stannis."

The exercise is now over.

"That was a professional performance," said Captain Dirk Steffen. It was evident that the Nigerian boarding team had undergone extensive training and were familiar with western military standards.

He does, however, see room for improvement. "You came on board without water or medical supplies," he told the team. An operation like this can take several hours, if not a whole day.

"You could easily become exhausted. In the event of injury, you wouldn't be able to cope on your own," Steffen said.

Without this exercise under the glaring heat of the sun, which pushed temperatures to above 30 C (86 F), this mistake probably would have probably gone unnoticed, until a real operation, perhaps against smugglers in the Gulf of Guinea, when it might have been too late.

'That will help us'

The Nigerians were delighted with "Obangame Express " - and not only because it drew their attention to unforeseen hazards.

"Over the last two weeks, three German soldiers visited us in our barracks and showed us tactics we hadn't used before," said one of the team members, who has served in Nigeria's army for 12 years. "That will help us and we'd like to thank them."

Shortly before the Nigerians leave the Hamburg, military mementoes are exchanged and a group photo is taken.

The boarding team jump into the speed boat and head off back to their frigate Thunder to track down real pirates and smugglers in the Gulf of Guinea.