I guess I was showing my provincialism. I got a private message from a guy named Marty, who wrote:
Hi Barnacle,
You and I live in a part of the world called IALA-B. Europe and Asia are IALA-A, where it is “Green Right Returningâ€. There is a long topic on the forum about that:
http://www.shipsim.com/ShipSimForum/index.php/topic,3566.msg36024.html#msg36024
Welcome to the forum.
Regards,
Marty
The topic is indeed illuminating on the subject of buoyage in different parts of the world, and on another subject that interested me: controlling vessels in SS.
Anyway, it turns out that the sim, and the AI ship, are correct: in England, it's Green Right Returning, to the dismay of American seamen.
Luckily, I didn't run aground!
Barnacle