Source:"Pirates fired a rocket-propelled grenade and machine guns Saturday in an attack on a luxury cruise liner off the east African coast, the vessel's owners said......Press Association, the British news agency, said passengers awoke to the sound of gunfire as two 25-foot inflatable boats approached the liner. The injured crew member was reportedly hit by flying debris."
Inflatable boats? So basically they could be taken out with a pellet gun. If you are set upon by pirates on the open sea, i suggest this shotgun (Model 870™ Marine Magnum™). It's motto is look good while you fight pirates.