The recent escalation in pirate attacks has highlighted the vulnerability of shipping off the coast of Somalia. Now many ships are taking their own precautions, using hi-tech equipment to keep pirates at bay.
A beefed-up international naval presence and United Nations resolutions giving foreign military vessels greater powers to chase the pirates have created little in the way of an effective deterrent.
But a consensus is emerging that ship-owners themselves could be doing more to prevent piracy.
So is there more in practical terms that ships' captains can do to fend off the pirates?
Wire and sound
Those who have witnessed attacks say the pirates tend to sneak up on one side of a ship.
They use grappling hooks and ladders to board it at the most vulnerable point - where there is least distance between the height of the deck and the water level.
Some vessels have strung barbed wire at those points, as recommended by the International Maritime Bureau in London. In some cases, say experts, this has proved effective.
Slippery foam sprayed onto the deck can also present a further barrier to pirates taking over.
Other possible solutions include electric security fences and blasting the pirates with water from fire hoses.
While hoses can be used to knock them off balance as they try to board a ship, they are thought to be of limited use against heavily-armed intruders.
Another weapon in a skipper's armoury are loudspeaker systems - or long-range acoustic devices - which provide a clear warning and can, in some instances, damage the hearing of potential unwelcome boarders.
One manufacturer describes its product as having a 'highly irritating deterrent tone for behaviour modification'.
An obvious deterrent is the deployment of more lookouts to give ample warning of a possible attack, supplemented by beefed up camera surveillance.
Skippers are also able to deploy sensitive radar, again, alerting them to imminent danger.
Use of arms
Controversial, though, is any proposal to arm crews.
The problem with this, says Will Geddes, managing director of International Corporate Protection group, is the risk of a protracted battle with already well-armed pirates.
John Burnett, author of "Dangerous Waters: Modern Piracy and Terror on the High Seas", says that of the 40,000 ships at sea today, most are crewed by people from developing countries.
"They've never held a gun in their lives, so you're asking them to arm themselves," he said.
"If you have guns for protection, you have to shoot to kill... even if you have the officers shoot, you're going to be shot back at and I think the chance of injury and death to the crew members, and damage to the ship, would be prohibitive."
John Burnett suggests thorough training of crew so that when they enter pirate territory, they are alert and assume that they are going to be attacked.