The  International  and  Inland  Rules  contain the  following  supplemental  information: Except for indicating distress and need of assistance, the use or exhibition of any of the foregoing distress signals and the use of other signals that may be confused with any of the those  signals  is  prohibited. Note the relevant sections of the International Code of Signals, Pub. 102, the Merchant Ship Search and Rescue  Manual,  and  the  following  signals: A piece of orange-colored canvas with either a black square and circle or other appropriate symbol (for identification from the air) (fig. 5-17), or a dye marker (fig. 5-17). The following signals, although not part of the Rules of the Road, are prescribed for submerged submarines  in  emergency  situations  involving  rising  to periscope  depth  or  surfacing: A white or yellow smoke flare fired into the air from a submarine indicates the submarine is coming to periscope depth to carry out surfacing procedures. Ships should  clear  the  immediate  vicinity  but  should  not  stop propellers. A  red  smoke  flare  fired  into  the  air  from  a submarine is a signal that the submarine is in serious trouble and will surface immediately if possible. Smoke flares of any color, fired into the air at short intervals, mean the submarine requires assistance. All ships in the area should clear the immediate vicinity but stand by to give aid. BUOYS LEARNING  OBJECTIVES:  Define  buoys. Recognize  the  International  Buoyage  Regions. Describe the IALA Maritime Buoyage System including buoy types, buoy colors, and buoy markings. Buoys are moored floating markers placed so as to guide ships in and out of channels, warn them away from hidden dangers, and lead them to anchorage areas, and so forth. Buoys may be of various sizes and shapes. Regardless of their shapes, however, their distinctive coloring is the chief indication of their purposes. Large  automatic  navigational  buoys  (LANBYs)  are major  aids  to  navigation,  and  they  provide  light,  sound signal, and radio beacon service. The LANBY is an all steel disk-shaped hull 40 feet in diameter. The light, sound signal, and radio beacon are located on the mast. Although buoys are valuable aids to navigation, they  must  never  be  depended  upon  exclusively.  Buoys frequently drag their moorings in heavy weather, or they may be set adrift when run down by passing vessels. Lights on lighted buoys may go out of commission. Whistles, bells, and gongs actuated by the sea's motions may fail to function in smooth water. INTERNATIONAL  BUOYAGE  REGIONS To reach agreement with all maritime countries to bring all buoyage into one system with the least amount of money and time expended, two international buoyage regions   were   established.   Figure   5-19   outlines International Buoyage Regions A and B. Navigational charts produced and/or printed after 1983 indicate the buoyage region to which the chart refers. MARITIME  BUOYAGE  SYSTEM Until recently, as many as 30 different buoyage systems were in use around the world. In 1982, most of the maritime nations of the world signed an agreement sponsored   by   the   International   Association   of Lighthouse  Authorities  (IALA).  This  agreement adopted  a  system  known  as  the  IALA  Maritime Buoyage  System.  The  system  provides  rules  that  apply to all fixed and floating marks other than lighthouses, sector  lights,  range  lights,  lightships,  and  large automatic  navigational  buoys  (LANBYs). The  Maritime  Buoyage  System  provides  five  types of marks that may be used in any combination. The five types of marks are lateral, cardinal, isolated danger, safe water, and special. Each type of mark will be discussed briefly here and in more detail later. 1. Lateral marks–indicate the port and starboard hand sides of channels. Within the Maritime Buoyage System there are two international buoyage regions where lateral marks differ. These buoyage regions and the different lateral marks will be discussed in detail later in this chapter. 2. Cardinal marks–used in conjunction with the compass, indicate that the navigable water lies to the named side of the mark 3. Isolated danger marks–erected on, or moored directly on or over, dangers of limited size. 5-26