Somali pirates are increasingly using hijacked merchant vessels with hostage crews as giant motherships to attack deeper into the Indian Ocean, the European Union anti-piracy task force says, according to Reuters. Forcing the original crew to operate the ship at gunpoint, pirates can now launch attacks during stormy monsoon seasons, forcing up ransoms, security costs and shipping rates. Until late last year, navies trying to secure regional sea lanes were facing some 500 young Somalis largely limited to skiffs and small boats powered by outboard motors and open to the elements. When naval officers referred to "motherships", they were simply referring to the largest small boat in a group. Even then, the pirates were wreaking havoc, redrawing shipping routes, driving up insurance costs and holding dozens of vessels and hundreds of mariners for months at a time. "The pirates are changing their modus operandi, taking ships which have been hijacked and sailing them back out into the Somali basin," said EU Naval Force Somalia (EU NAVFOR) spokesman Wing Commander Paddy O'Kennedy. "Their previous way of doing things was very dependent on the weather. Now they are using larger ships, the weather is having much less effect on their operations and they can travel further." When EU aircraft overflew the vessels, officers at EU NAVFOR's headquarters at a British military base outside London say the pirates swiftly threatened by radio to kill the hostages or lined up prisoners on the deck with guns to their heads. Grain and oil shippers said this month rising piracy might force them to reroute vessels around the Cape of Good Hope, potentially further pushing up global food and energy prices. PIRATE TANKER Somali pirates have now mounted attacks within 150 miles of South African and Pakistani waters and 250 miles of India. The level of force used is also rising, with one ship attacked with six rocket propelled grenades during a hijacking attempt. EU and other commanders had expected a falloff of attacks in December and January as monsoon waves made it impossible to beach-launch small boats. Instead, they found themselves facing what seemed like almost a coordinated surge of up to eight large hijacked ships, smaller skiffs ready on their decks ready for boarding parties with AK-47s, RPGs, ladders and grappling hooks. The EU estimates between two and eight such ships are now out in deep Indian Ocean waters at any one time, carrying 20-30 pirates as well as a similar number of hostages from the original crew. Ships used to attack others included at one stage a 146 metre South Korean tanker -- since freed by South Korean commandos in an a rescue that killed eight pirates. Others include freighters and factory fishing vessels. Other states including Malaysia and Russia were also using force to retake hijacked ships of their own nationality, they said.European forces have largely avoided trying to retake vessels. "We're always looking at the way we do business but the safety of the hostages is our primary concern," said O'Kennedy. The EU force says the fact the number of actual hijackings has remained roughly constant despite rising pirate numbers is a sign of success. Naval patrols have made the key Gulf of Aden chokepoints safer, although the wider ocean remains dangerous. With the payout for an individual pirate up to $50,000 for a successful hijacking, and the highest ransom to date for a cargo ship some $9 million, there is no shortage of young Somalis willing to take the risk and fuel the problem further. O'Kennedy pointed to the widespread poverty and lawlessness in Somalia. "We are simply treating the symptoms of the situation onshore," he said.