If so they had enough intelligence data to position the dhows 450 nm out or they'd never catch the tanker. I'm guessing the boys may have upgraded their gear, though.
I think the general view of merchant sailors is a little more aggressive than the ones I know merit. They're just working stiffs doing a rather tough and dirty job, and risking their lives to protect their cargo is not in the job description, especially if it involves shooting firehoses at people armed with RPG's and automatic weapons. The pirates have taken (relatively) good care of past hostages, enough to prevent a life-or-death scenario from the point of view of the sailors.
More likely it will take armed professionals to oppose armed professionals (yeah, give me a cupie doll for a golden revelation on that one). It simply becomes a question of who, and when. But it will most definitely involve attacks on a civilian population and a risk of death for hostages. So who bells the cat?