It seems to matter little how many of the world’s warships gather in the Gulf of Aden to deter acts of piracy. The pirates still manage to ply their trade and in recent weeks there has been a spike in ship hijackings, including yesterday’s capture of a British-owned vessel.

How can it be that with so much focus now on countering the pirates, they remain a significant threat to international shipping? There have been more than 40 attacks since the beginning of the year, ten of which were successful.

With 1.1 million square miles of water to cover just in the Gulf of Aden alone, the international warships operating in the area have never been able to guarantee safe passage for the thousands of ships that transit the routes. They rely, instead, on the merchant seamen on board the vessels sticking to certain rules if they wish to complete their journey without being commandeered. To make ships' voyages still more dangerous, there is now evidence some of the pirates are switching their tactics and hunting in the Indian Ocean.

On any day, there are between 15 and 20 warships on counter-piracy patrol in the Gulf of Aden from different navies that range from the United States and Britain to Russia, China and India. To underline the concerns that piracy have raised, there are three separate organisations involved - the US-led Combined Task Force 151, Nato and the European Union with Operation Atalanta. Countries such as Russia and China are not part of these operations, but apparently there is good communication between all the warships.

To make their job slightly easier, all merchant ships are advised to use the special international transit corridors - one going east, the other, west - across the Gulf of Aden where the foreign warships can then concentrate their efforts. There have been successes. Of the 40 attacks this year, ten were foiled by the intervention of one or more of the warships. A military helicopter hovering over the hijack-area is often more than enough to send the pirates fleeing.

The EU naval force which currently does not include a Royal Navy warship has succeeded in detaining 16 pirates so far this year, and the combined number of arrests carried out by all the foreign ships is more than 100 since January 1. The EU has an arrangement with Kenya for arrested pirates to be dealt with through their judicial system, and the first trial is due to take place this month.

The transit channels, however, are 500 miles long and, even within these more confined areas, it is still not possible for the warships to be everywhere. The pirates, operating in small boats that provide no reflecting radar blips, have adapted their methods, and have become more heavily armed to present to targeted vessel crews a significant threat to their lives.

The counter-piracy maritime organisations urge the merchant crews to take a number of steps to deter pirates. These include putting barbed wire around their vessels to make boarding more difficult and to ensure that they have crew members manning the hoses. Delay is important. If the crews can hold off the pirates for any length of time, the chances are that the nearest warship can get within helicopter reach of the incident and send the pirates packing.

The merchant ship-owners are also recommended to keep their vessels 600 miles away from Somalia’s eastern seaboard from where most of the pirates emerge. Not all the merchant ships, however, conform to the rules. Some fail to use the transit routes, and others give scant attention to installing anti-piracy defences.

Why the spike in attacks now? There appear to be two reasons. First, the monsoon period is over and, second, the pirates are apparently low in stocks of hijacked vessels and need more to maintain their income and to sustain the lifestyle they have enjoyed as a result of the huge ransoms paid by shipowners.

“Ultimately, this problem is not going to be resolved at sea but on land [by the authorities in Somalia], but meanwhile the pirates are continuing to thwart all the efforts being made by foreign navies to stop them,” one military source said.

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