I'm sure some vital facts are missing from the story, but some questions for those in the know:
Would it be normal (if say, the last encounter hadn't happened) for a destroyer to alter course to avoid these freakin' Iranian pangas? I can understand that attempted radio contact would be proper procedure, as well as the horn blasts. However, given the situation appearing to be in international waters, I can't help but think if the last incident didn't happen, the destroyer would have kept on its way, with the idea that a bicycle shouldn't play chicken with a Mack truck.
Yes, it would be normal to change course.
(a). Nothing in these Rules shall exonerate any vessel, or the owner, master or crew thereof, from the consequences of
any neglect to comply with these Rules or of the neglect of any precaution which may be required by the ordinary
practice of seamen, or by the special circumstances of the case.
(b). In construing and complying with these Rules due regard shall be had to all dangers of navigation and collision and
to any special circumstances, including the limitations of the vessels involved, which may make a departure from these
Rules necessary to avoid immediate danger.
Basically it is the responsibility of all ships at sea to avoid collision. If your vessel hits another, no matter what the circumstances are, you are at least partially at fault, and can be held liable. This applies to ships of war as well. So regardless of the Iranian's actions or playing chicken, the captain of the destroyer had a legal responsibility to take action and avoid collision if he deemed risk of collision to exist.
Additionally:
(a). Any action to avoid collision shall be taken in accordance with the Rules of this Part and shall, if the circumstances
of the case admit, be positive, made in ample time and with due regard to the observance of good seamanship.
(b). Any alteration of course and/or speed to avoid collision shall, if the circumstances of the case admit, be large
enough to be readily apparent to another vessel observing visually or by radar; a succession of small alterations of
course and/or speed should be avoided.
(c). If there is sufficient sea-room, alteration of course alone may be the most effective action to avoid a close-quarters
situation provided that it is made in good time, is substantial and does not result in another close-quarters situation.
He can't just tweak it a couple of degrees to Starboard, he's supposed to make a pretty decent change so that everyone knows he's maneuvering to avoid the collision.
Depending on exactly where the Iranian's were in relation to the destroyer he he may very well have been
required by international law to change course and/or speed. The relative positions of the two vessels is what determines which vessel has the right of way, and which is burdened.
That's the legal answer. Functionally, little two bit navies do this all the time, especially in the Persian Gulf and Red Sea. They feel like they've accomplished something by making a US vessel change course. It's been happening, daily, since at least 1991. The Saudi's are actually worse about it. And, Yes, US military vessels are required to follow the international law and make sure a collision does not occur. So we go around them. Completely normal for a Hormuz transit, and not indicative of a change in either countries behavior from the Farsi Island stupidity.
