Ping, Dragartist, thank you for the information.Not wise of the existence of the book.
With the information I have located which are the buoys, though the document is not said which is one of them (type 300.. ???).
In this case the Nimrod it was not patrolling an area, was going in traffic to a WP and the throwings of the buoys were spread in the time and to an alone buoy.
I have mas doubts of the documents but though they are classified, understand the situation.
Thank you.