Yeh, they have hijacked entire tankers in the past and are a major danger to shipping.To solve the problem they need better security measures on commercial shipping and need to expand the seaguard's battle with piracy. It is impossible to track everyone but at least better order can act as a deterrent.
I met someone who worked on a tanker in that area for a while and he said he was always worried about that people might try something. He told me a funny story about his experiences. Him and his mates where originally sailors who operated in the North Sea and didn't know how to swim because the water was so bloody cold. His company relocated him to South East Asia and these Brits were given a training course there about what to do if pirates attacked. Because they did not always have sufficient security to safely deter a boarding action, they were advised to escape in a motor launch. If for some reason a launch was unavailable they were to jump in the sea, and hope that other friendly shipping could pick them up, so they all learnt how to swim. To complete the final section of the safety course they had to stage a sea rescue.
"If you are low enough to jump into the water with your life jacket on, you can do so because the water is very warm. Now, what should be done to rescue a friend in the water?", said the instructor.
"Lucky we can swim now", a man whispered to his friend.
The instructor threw in a plastic dummy with a life jacket. Almost immediately, just as someone was about to answer, the dummy was savagely mangled and ripped into pieces. The sailors looked on in bewildered astonishment as the frenzied sharks continued to thrash around the test subject.
"Bugger. I think I'll stay with the pirates thankyou".