European naval officers fighting piracy off the Somali coast have warned that with the onset of the piracy season this month and the pirates' success ratio declining, it is probably only a matter of time before a sailor gets killed during negotiations.
They also warn that detention periods for captured crews have trebled in the last two years, from 40 days to 120 days, and that ransoms being demanded - and paid - are breaking new records.
Piracy is now a scourge right across the Indian Ocean, and anyone who has been a victim will never forget it.
James Grady was second engineer on board the Saudi-owned supertanker Sirius Star when it was seized by pirates two years ago.
"I was working on the deck when the pirates were first spotted," he says.
"I saw them coming closer. I could see they had rocket-propelled grenades and Kalashnikovs. About 15 minutes later they were on the bridge."
That was not enough time for the European Union's naval force, Navfor, to come to the rescue. But with their dozen or so warships patrolling off the Somali coast, Navfor's officers say they have disrupted more than 90 hijackings so far this year.
In a well-staffed operations room at Navfor's headquarters at Northwood, just outside London, I asked one of their intelligence officers - who asked not to be named - what he expected in the coming months.
"We expect from now until December to be very busy. We expect pirates to be active and more intense than before," he said.
"What's interesting is ransom demands look set to increase, as do ransom payments. And we're seeing the length of duration vessels are held is also increasing.
"This is of concern to us because as length of duration increases and there is more money involved, then the negotiations become more protracted as each side holds out for a better deal. One concern of ours particularly is the pirates will become more violent during the negotiation."
'Relying on fear'
Navfor's assessment is that the pirates' success ratio - the number of successful hijackings versus the number attempted - has dropped from 50% a few years ago to 20-30% this year.
This is partly in response to the international naval presence in the western Indian Ocean, known as the Somali Basin, and partly due to the fact that pirates are now roaming extraordinarily long distances away from their home shores, up to 1,000 nautical miles (1,151 miles/1,853km) or more, in search of prey.
When they do capture a ship, and its cargo and its crew, they have a number of ways of putting pressure on the owners to pay a ransom.
Navfor's intelligence officer doubts the pirates would deliberately murder a captive in cold blood but that if one was killed during ransom negotiations then this risked becoming established practice. He describes a terrifying incident last year.
"There was a vessel last year, 30-plus crew on board, all grouped together in one area of the ship and the pirates fired automatic weapons around them for more than 15 minutes.
"Subsequently, they told three of them they would be taken ashore and if the company didn't raise their offer, they would kill them," he says.
"Then they gave them their own telephones to phone home. They are relying on the hostages' fear, allowing the family to apply pressure to the shipping owner. It's a standard technique."
Nodding quietly in agreement is Navfor's Chief of Staff, Colonel Richard Spencer, a British Royal Marine.
His staff have done extensive interviews with sailors once they have been released after ransoms are paid, and many have talked about the unstable, volatile atmosphere once pirates get on board.
Surprisingly perhaps, one of the most dangerous periods is after a deal is agreed and the ransom package is dropped off, usually by light aircraft.
At this juncture there can be up to 70 pirates on the captured ship, all eager for a slice of the takings and fights amongst them have been known to turn deadly.
"We need to bear in mind that the pirates are constantly taking a substance called khat, a drug which affects their state of mind. They mix that with alcohol and whatever medication they can find on the ship. So these are not rational actors," says Col Spencer.
To date, Somalia's pirates have never murdered anyone in cold blood, but clearly there is a risk that could change.
For mariners like second engineer Grady, sailing through the western Indian Ocean brought a traumatic, life-changing experience, and while he acknowledges the work of the EU's navies, he does not believe the pirates are about to see their activities closed down.
"The main problem in Somalia is there are no policeman there to arrest them when they go ashore. There is no legal infrastructure.
"The world's navies have had great success because they are operating close to Somalia, they're catching them on the way out. They're not catching them all of course, that would be impossible.
"People who don't work at sea can't imagine the distances involved, its millions of square miles of ocean to cover, you would need hundreds of thousands of warships to be truly effective".