It's GREAT to be me. --- "45% liberal/55% conservative"
Diplomacy is the art of saying 'nice doggy" until you can find a gun.
"I do not underestimate the ability of fanatical groups of terrorists to kill and destroy, but they do not threaten the life of the nation. Whether we would survive Hitler hung in the balance, but there is no doubt that we shall survive al-Qa'ida." -- Lord Hoffmann
Don't discount the possibility of their using these ships as a provocateur or bait.
Think about it. Strait of Hormuz. Place the four large cargo ships in the strait. Scuttle them. Congratulations, You just shutdown all shipments of oil out of the Gulf. Any predictors of what that will do to world oil and gas prices? Iran's navy damage capacity is a peashooter compared to what it can do with four old cargo ships.
"If your opponent is of choleric temperament, seek to irritate him." - Sun Tzu
What would the provocation serve other than to usher a crushing military response from us?
But, you never know.