The north and south cardinal markers are easy to identify since they point up (North) or down (South). But for the East and West I need a memory aid and the one I was taught at school for my 'Seamanship & Nautical Knowledge' 'O'-level is 'WOOL WINDS WEST' as it looks like a spinning bobbin, and DIAMONDS IN THE EAST when the two triangles form a diamond shape.Incidentally, my O-level was earned by opting to take the course at Oban High School as part of the Friday afternoon 'Training for Leisure' program. We were told that with the advent of computers we should prepare ourselves for a surfeit of leisure............sadly it hasn't work out that way but I loved the course; and do admire the new buoys!
Many thanks for the comment, John, and for giving me a way of remembering which is which.Alastair MacColl writes to say that cardinal marks also have characteristic colourings, perhaps best seen by Googling 'Cardinal Marks' - though there's a good picture at http://visual.merriam-webster.com/transport-machinery/maritime-transport/maritime-buoyage-system/cardinal-marks.php
My mnemonic is "Eggs is east". I don't understand the NLB's fetish for replacing the old red and green (or black as the latter used to be) port and starboard hand boys with cardinals. The solid red and green is so much easier to identify than the yellow and black banding and red and green lights at night are instantly recognisable compared with trying to remember which of four different sequences of white flashes you're looking at!