@hawkeye10,
You are wrong on several counts, some that Setanta has noted and others as well.
The major forces preventing the arming of the crews of merchant ships are the various sefarers unions and the insurance companies that insure the owners for injuries to crewmen. Given that they are usually the same underwriters who insure the vessels & cargo, they could easily be motivated to change their policies. However, behind all of this is the nonsensical insistence of Western Governments that their domestic legal processes must be applied to the treatment of pirates acting in international waters. This too limits the potential arming of ship's crews. To make matters even more foolish, the European naval vessels operating off the horn of Africa deal only with assaults on their own flagged ships and, absent an onboard magistrate (sic !) actually release any pirates they catch.
The Somali coastline is about 1,500 miles long. The pirates are operating in small boats, launched from mother ships as far as 500 miles off the Somali coast. There aren't enough naval escorts in the western world to effectively patrol this huge and heavily travelled ocean area using the methods now in force. It seems clear from their many successes that the pirates have access to modern communications and ship routing data: this is much more than a random collection of displaced Somali fishermen.
Until very recently piracy was treated as a crime against all nations and pirates as effectively at war with all as well. Thus preemptive military action was warranted and trial & punishment by military tribunals was the rule for those captured. Under these principles our naval forces would be able to simply destroy & sink any mother ships so identified, without waiting endlessly to observe them in the act of launching an attack. This could easily end the piracy in a matter of weeks. Some continued enforcement would undoubtedly be needed, but soon those financing the operations and even the Somali teenagers manning the boats would calculate the odds and act accordingly.
However all this has become decidedly unfashionable, as Prtesident Bush discovered with respect to terrorists who were defined similarly by the previous administration. Meanwhile we will enjoy the spectacle of the forthcoming terrorists trials in our domestic courts.