North bound from Casablanca to Antwerp on a bulker last Tuesday morning (doing a Navigational Assessment) experienced my first Virtual Navigation Marks? I had read about them as an idea in SEAWAYS some time ago but these were the first and only ones I've experienced. They mark the east/west extremities of the Ushant TSS and look like red blobs on the ECDIS charts. For the Filipino navigators and Captain of the vessel they were the first that they had come across. There were the usual jokes about colliding with one on the TSS approaches and the comment that USHANT TRAFFIC CONTROL would probably report it to Port/Flag State as a collision!
The mind boggles just thinking of what Varley and Barrie Youde may have to say on the subject, but does stretch the imagination!