Gormless, in October last year NATO announced that it would send its Standing Naval Maritime Group 2 to the waters off Somalia within two weeks in an operation called Allied Provider, but this was only to ensure food got into Somalia for humanitarian aid. So there has been a patrol for several months.
The US (Africom) are considering land based attacks to flush out the pirates, as they have a lot of land based support and they are also some international assistance in getting the Somalian Government to set up and maintain its own coast guard services which it currently doesn�t have.
It seems a lack of resource, inclination and coordination might be the issue, as well as preference for diplomacy rather than military action. Any actions, whether diplomatic or military, would need the support of the Somali people, who are traditionally suspicious of foreign intervention. Engaging with the pirates on the sea by military means in isolated instances might save the day � providing it accords with the Geneva Convention, but that protection is only watering one tree, not taking care of the whole forest.