I read the BBC news feed of this last night my time.. (it has since been "revised") and it said something along the lines of "it is unknown why the ship fired on the small motor boat" (this has been edited out) and was followed immediately by the paragraph "Al-Qaeda militants have in the past used small motorboats to attack US military and other foreign vessels in waters off the coast of Yemen, our correspondent adds. "
Kinda telling of their attitude towards the situation.