Signalman 1 & C - Historic Naval Ships Association

TopmarksBy day, topmarks are the most important featuresof cardinal marks. The arrangement of the cones mustbe memorized. For north, the points of the cones is up;and for south, the points of the cones is down. An aidto help you memorize the west topmark is that itresembles a wineglass. Cardinal marks carrytopmarks, whenever practical, with cones as large aspossible and clearly separated.ColorBlack and yellow horizontal bands are used tocolor cardinal marks. The position of the black band,or bands, is related to the point of the black topmarks.The black and yellow horizontal bands are used asfollows:North—Black bands above yellow bandsSouth—Black bands below yellow bandsWest—Black band with yellow bands above andbelowEast—Black bands above and below yellowbandThe shape of a cardinal mark is not important; butin the case of a buoy, it will be pillar or spar.Light CharacteristicsWhen lighted, a cardinal mark exhibits a whitelight. The characteristics are based on a group of quick(Q) or very quick (VQ) flashes, which distinguishes itas a cardinal mark and indicates its quadrant. Thedistinguishing quick or very quick flashes are asfollows:North—Very quick flashing (VQ) or quickflashing (Q)East—Very quick flashing every 5 seconds (VQ(3) 5s) or quick flashing every 10 seconds (Q (3) 10s)South—Very quick flashes followed by a longflash every 10 seconds (VQ FL (6) + LFl 10s) or quickflashing followed by a long flash every 15 seconds(Q (6) + LFl 15s)West—Very quick flashing light every 10 seconds(VQ (9) 10s) or quick flashing every 15 seconds(Q (9) 15s)As a memory aid, associate the number of flashesin each group with a clock face (3 o'clock, east; 6o'clock, south; and 9 o'clock, west).The long flash immediately following the groupof flashes from a south cardinal mark is to ensure thatits six flashes cannot be mistaken for three or nine.Quick flashing lights flash at a rate of either 50 or60 flashes per minute. Very quick flashing lights flashat a rate of either 100 or 120 flashes per minute. It isnecessary to have a choice of quick or very quickflashing light to avoid confusion. Two north buoysthat are placed near enough to each other to bemistaken is one example where the quick flashing orvery quick flashing lights would be needed.ISOLATED DANGER MARKSAn isolated danger mark (fig. 9-16) is erected on,or moored above, an isolated danger of limited extent.An isolated danger mark has navigable water allaround it. The extent of the surrounding navigablewater is not important. The isolated danger mark can,for example, indicate either a shoal that is wellFigure 9-16.—IALA Maritime Buoyage System isolated danger marks.9-17