One year since UK couple Paul and Rachel Chandler were taken hostage by Somali pirates, the BBC's East Africa correspondent, Will Ross, looks at how the fight to end piracy is going.
"When we come across a boat with ladders on board, we can be sure they are pirates," says a senior member of Nato's anti-piracy task force.
"After all, there are no known window-cleaning operations in the Indian Ocean."
More often than not, when the international warships capture these pirates, they disarm them, leave them enough fuel to get back to Somalia and set them free.
The pirates have even on occasion managed to get their engines overhauled courtesy of some naval expertise.
"There is obviously massive frustration," said Lt Cdr Simon Ward aboard the Danish warship, Esbern Snare.
"We are out here to eradicate piracy. We are achieving that, in a way, but we are not sending people through the courts, which is what we would like to see more of.
"But we are doing the best we can given the situation we've been given."
Catching suspects in the act of piracy is extremely difficult, and possessing pirate paraphernalia is not enough to stand up in court.
Few countries are willing to prosecute the pirates, and unless that changes, the deterrent is weak.
At any given time there are up to 30 warships operating in the Gulf of Aden and the Indian Ocean, but the navies are having only limited success.
Without the warships, the picture would be far worse as they are managing to deter and disrupt piracy. The problem is one of scale.
"When you look at the Somali basin, it is basically the size of Western Europe," says Commodore Christian Rune, commander of Nato's anti-piracy task force.
"It's like patrolling Western Europe with a couple of police cars - there is no way you can respond to every robbery."
The Nato task force has been urging the cargo vessels to do more to protect themselves, including travelling at high speed in the dangerous areas, and putting extra look-out crew - even dummies - on deck.
Another possibility is building a strong room into which the crew can retreat before pirates get aboard. This buys time for a warship or helicopter to rescue the ship as the pirates cannot move the ship or get to the highly prized crew.
Nato now says many of the successful hijacks are against ships which ignore the advice, known as Best Management Practice.
Although figures vary, some reports say the pirates are currently holding 26 vessels along with 486 crew. From this they will receive tens of millions of dollars in ransom.
The crew aboard the Esbern Snare even refers to the pirates having a "business plan". It might seem like a strange turn of phrase, but it is spot on. This is big business, which evolves as the circumstances change. As the international naval operations have become more co-ordinated and efficient, the pirates have expanded their area of operation.
It is rare to get a glimpse of a pirate lair on the Somali coast, but Nato says it knows of at least nine locations.
The task force has images of one lair, which it has called Great Pumpkin, where ladders for scaling the sides of vessels are on display alongside barrels of fuel and water.
There is no shortage of the small boats known as skiffs at Great Pumpkin, and there are also larger whalers or mother ships which have become vital these days as the pirates head more than 1,000km (620 miles) out to sea.
Behind the boats are the 4x4 vehicles - bought from the piracy proceeds.
The warships get within a mile of the Somali coast, and the crews can watch the pirates making preparations, but they have no mandate to take any action.
In fact, no-one has a mandate. Even the Somali government has no control over these well-guarded bases, and as long as Somalia is engulfed in conflict, that situation is unlikely to change.
Meanwhile, the impact of piracy is continuing to disrupt trading and commerce all around East Africa.
In the Kenyan port of Mombasa a Chinese cargo ship is unloading mobile homes for a Chinese oil company. It is then heading to South Africa, where it will pick up coal and other minerals for China.
"Normally the journey from China to East Africa takes 21 days. But because of the pirates, we had to go around the southern tip of Madagascar and it took five days longer," said Zhang Guosen, the captain of the 30,000-tonne Le Yi.
He has taken a few of the recommended measures in order to make it harder for pirates to get on board, including wrapping barbed wire around the side of the ship.
But Mr Zhang looks exasperated when asked about the operation to stop the pirates.
"When the warships catch the pirates, they send them back to Somalia. That's not a good idea. They go home, get more weapons and go back to sea to do more piracy," says Mr Zhang.
"There is no risk for the pirates. We are too soft on them. They should be locked up for a very long time."
The navies even end up catching the same pirates twice. Without more convictions, the status quo looks set to carry on for years. The question is whether the warships can afford to stay that long.