Which waterway?
Do you know what international waters means?
Besides which no one is claiming the yacht was in international waters, it rests entirely on the right of innocent passage in territorial waters.

They don't, the problem is there aren't any clear markers (like a line of buoys for instance) to mark where exactly the line between their waters and international waters are. So it's really a matter of estimation for your average patrol boat. And the fact that they're British gives them all the more reason to watch them like hawks, because the Anglo-Iranian history is not exactly a pleasant one. Occupation and threats flying from both sides during World War II, two coups by the Brits with the aid of the CIA (which put Dr. Mossadegh in power, but when he wouldn't agree to simply hand out free oil to the two nations, they removed him and reinstated the monarchy), combined with their support for the Iraqis during the Iran-Iraq War through funding and weaponry secrets (along with the United States, they gave Iraq poison gas secrets and funding).

The rights to the Shatt-al-Arab waterway is very complex.

Iran and Iraq have been fighting over the Shatt-al-Arab waterway for a very long time. Even before there was an Iraq or Iran. The first treaty for this waterway was in 1639!

The Algiers Agreement of 1975 established the border along the thalweg principle (mid-river) and was later rejected by Iraq. However the Algiers agreement of 1975 still remains the "official" treaty on this issue.

It was this waterway and rights to navigation that was one of the reasons for the Iran-Iraq war in the 1980's.

In the 1990's Iraq drained some marshlands in an attempt (successful) to redirect the waterway in order to claim total control. The original intent of thalweg was to always have the border along the deepest portion of the river (theoretically in the middle). This means that the border can change depending on where the deepest part of the river is. Hence the desire of the Iraqis to change the flow of the river. However interpretations of the '75 treaty treated the border to be static and consisting of straight lines. Arguments pro/con this interpretation continue to this day.:damn:

The rational was that static borders and ones consisting of straight lines makes it easier to control the border. Both sides agreed but disagreed on where the straight lines should be.

This was compounded by US attempts to "restore" the marshlands in early 2004, but also in a way that favoured Iraq.

UNSCR resolution 1723 authorized the British to patrol the waterway and this further pissed off the Iranians. The British patrol in accordance to the 1975 treaty and the "static" interpretation.

Hence, the Iranians are very very sensitive of anyone infringing on what they consider "their" side of the waterway. These captures and releases (there have been at least 8 in the past few years) are not frivolous. In order for the Iranians to be able to make their case for redefining the borders, they have an obligation to enforce (through their actions) border security or risk losing their claim of sovereignty.

This is why the Iranians always catch and release any "invaders". This is also why other countries, especially the US, need to stay out of these issues and allow the Iranians to do what they really have to do without making a big deal out of it.

However, since the US has a policy of always interpreting Iranian actions in the worse possible light, our press and our State Department often have to make bellicose statements, which the Iranian government ignores and release as they originally intended.

This gives the US State Department the chance to pat themselves on the backs and proclaim that the "hostages" were released due to their intervention. Yeah, whatever. :nope:

More than you probably wanted to know about the Shatt-al-Arab waterway, and I have only briefly touched on the major points. This is a complicated and complex issue. But rather interesting actually. :)

But Platypus this incident was not in the Shatt, it was in the Gulf itself.
Though as you mention the patrols in that waterway and the associated problems then the second incident with the RN was outside the river and the dispute centred on competing claims of extention of the thalweg line out to sea which had never been adressed let alone resolved. That is why the second incident wasn't covered by the UN resolution and the British admiralty had declared it off limits for patrols.

I suppose it would be easiest just to mention for Blacklights information that the whole lot of waters, be it the straights, the gulf or the Shatt al arab simply don't contain anything that is legally international waters.

That is correct that this incident took place in the gulf. My comment was aimed at the people referring to the waterway, not specifically this incident.

But he cannot have been refering to the shatt as Iran has never claimed the whole of it and it couldn't possibly be termed international waters.

Parading the "captive invaders" in their news like they usually do doesn't help their cause either IMHO. They seem to view EVERYTHING as an attack against them. Even people on a drifting sailboat waiting for a tow was seen as a threat by them. Please.
If the US found a boat of Iranians disabled and drifting into our waters, they would not be rounded up, captured, interrogated, paraded down the streets and in the news as captured spies, etc...
More than likely, the coast guard would end up rendering asistance (Unless there was something VERY suspicious about them being there or say if they're carying drugs or weapons).

Hold on Blacklight, didn't the coastguard arrest that sailor and sink his boat.
You know the fella that was doing a solo crossing of the Atlantic in a row boat in an attempt to set a new world record.:rotfl2: