This explanation is certainly interesting:
The official version of events was questioned by Yulia Latynina, a leading Russian opposition journalist and commentator.
"The Arctic Sea was carrying something, not timber and not from Finland, that necessitated some major work on the ship," she wrote in the Moscow Times newspaper on Wednesday.
During two weeks of repair works in the Russian port of Kaliningrad just before the voyage, the ship's bulkhead was dismantled so something very large could be loaded, she wrote.
"To put it plainly: The Arctic Sea was carrying some sort of anti-aircraft or nuclear contraption intended for a nice, peaceful country like Syria, and they were caught with it," she said.
That would explain the motive since the value of the cargo--and the value of the secrecy about the cargo--would make an operation like this worth it.
It does not, however, explain why criminals would believe they could extort money from a Russian government's secret project to export such a sensitive cargo. Who did they think they are, SPECTRE? More like KAOS, under the circumstances.
Which may mean that the simple explanation is real--stupid criminals went after a ship that just really wasn't worth it.
But this is Putin's Russia, so I can't quite buy the simple explanation yet.
Just what was on the Arctic Sea?
UPDATE: Interesting. So it took three large cargo planes to move fewer than a score of men and they were taken to the former KGB's infamous prison?
Russian federal investigators said they were questioning the sailors and the eight suspected hijackers. Interfax news agency said both groups had been brought to the notorious Lefortovo prison run by the main KGB successor agency.
...
The group was reportedly brought to Moscow in three heavylift Il-76 transport planes, each capable of carrying 40 metric tons (44 tons) of cargo.
It was unclear, however, why three planes were needed to fly a small group to Moscow, and why one of Russia's largest planes — often used to transport heavy weapons and other balky cargo — were used for the operation.
The Russians sure take their timber thefts seriously. One shudders to think what the Russians would do if state security was involved.