By Nick Rankin
BBC World Service
Pirates are not just mythological characters with peg legs, parrots and pistols. They now carry AK-47s and use speedboats to rule the high seas of the world.
Piracy is a major problem off the Somali coast
Robbery of the high seas is not confined to 18th-Century history and literature or Hollywood films - it is still very much alive today.
Ninety percent of the world's trade is still moved by sea, so it is not surprising that piracy against cargo vessels remains a significant issue.
It is estimated that seaborne piracy costs the world tens of millions of dollars a year.
Piracy peaked in 2003 with 445 attacks around the world and since then, they have more or less steadily come down.
In 2006, there were 239 attacks. Last year, the number increased slightly to 249.
Although attacks have decreased from the early 1990s, Rupert Herbert-Burns, a maritime security expert at Lloyd's Intelligence Unit, says piracy is still a worrying problem.
"Attacks rose by 14% towards the end of last year, largely due to attacks off the Horn of Africa, specifically in Somali waters or in the territorial waters off Somalia," he said.
According to the International Maritime Bureau, which runs the piracy-reporting centre in Kuala Lumpur, pirates attack different kinds of vessels for a variety of reasons.
In Nigeria, pirates tend to attack vessels involved in the oil business, while in South East Asia, mainly small tankers, tugs and barges are seized.
Cargo is often stolen from barges and crew members are kidnapped and held for ransom.
In Somalia, any merchant ship is a potential target and they are advised to stay at least 200 miles off the Somali coast.
Somalia is a unique problem, because there is no effective central government and no navy to protect its territorial waters.
The country has been at war for almost two decades and piracy has now become a way of making money.
Andrew Mwangura, who runs the Kenyan Seafarers' Association in Mombasa, thinks that piracy has become a way of life for many young Somali men, as they simply do not know any better.
"All my life, I don't know what life is, so if someone gives me a gun and tells me to go and make a living, they go and do that," he said.
Many young men have no education and no understanding of the rule of law.
Somalia has no navy, so many militia groups have taken it on themselves to deal with the problem of illegal fishing.
"Illegal fishing costs Somalia $6m annually and around 800 vessels from around the world are involved," says Mr Mwangura.
Pirate fisherman provide cheap fish for home markets, Somali pirates support their towns and villages. That raises a key question: is helping your own people good or bad?
Held to ransom
"All the attacks off the coast of Somalia are aimed at hijacking for ransom," says Capt Pottengal Mukundan of the International Maritime Bureau.
Some pirates have been brought to justice in Somalia
"The idea is to seize the ships hundreds of miles off the coast, force the ship well inside Somali waters and then the hijackers keep the ship until the owners pay an agreed ransom for the return of the ship and crew."
The amount of money that is demanded by pirates is often substantial.
"In all cases where the vessels have been released in Somalia, they have been paid," says Capt Mukundan.
When a Danish cargo ship, the Danica White, was seized by Somali pirates in June 2007, the ransom paid to secure its release was reportedly as high as $1.5m.
Defining the law
A piracy attack is an attack against a vessel that happens in international waters.
However, attacks that happen inside territorial waters, which are normally 12 nautical miles from the coast, are deemed as acts of robbery.
The laws that govern this distinction also determine the type of response that can be initiated.
For example, if a naval or coastguard vessel is a witness to an attack by pirates who manage to get into territorial waters, they are often forced to break off the right of "hot pursuit", as they do not have the permission of the relevant sovereign government to be in those waters.
As Mr Herbert-Burns of Lloyd's Intelligence Unit recalls, that is exactly what happened in the case of the Danica White.
"Two days after the attack, a United States naval vessel tried to intercede and fired shots across her bow," he says.
"The Danica White then managed to get inside Somali territorial waters and the United States naval ship had to break off pursuit for that reason.
"No one nation has a responsibility for policing international waters. We are reliant upon countries which have an economic or strategic interest in maintaining the security of sea lanes of communication."
An organisation called Taskforce 150 has been in operation since 2003 and involves naval forces from many countries including the US, Britain and Pakistan.
Without help from other countries, it is very difficult to imagine whether Somalia will have sufficient resources and infrastructure to deal with piracy itself.
Pirates, a three-part series by Nick Rankin, on BBC World Service.