Visual aids to navigation : using lamps or fire to indicate location at night

Basic Requirements

  • Aids should be seen within the required range
  • Aids should be clearly separated from other lights with certain features to allow for seafarers or observers to identify them without difficulty
  • Blinking intervals should remain constant and accurate, and easy to identify by seafarers
  • Lanterns and light sources should have high efficiency and credibility as far as possible
  • Aids should comply with proper safety standards in order to meet usages requirements and purposes of aids with regard to geographical navigation

Types of Visual Aids to Navigation

Types of Visual Aids to Navigation
Type Description
Lighthouse Manned Lighthouse
Manned Lighthouse
A tower containing a powerful flashing lamp that is built on the coast to guide ships, indicate location of a harbor or gates of a port. It is also used for ships to determine their own location or where land falls.
Unmanned Lighthouse
Unmanned Lighthouse
Light Pole Light Pole With the same purpose as a lighthouse, it has the simpler structure of a pole with floating lights
Light beacon Light beacon It is a structure located on shoals and reefs to indicate the existence of dangerous obstacles or routes near the navigating routes. If it has light fixtures, it is a light beacon, if not, it is a beacon
Illuminating light Illuminating light A tower with a projector reflecting high intensity light on reefs or the top of breakwaters to inform vessels of the existence of the obstacles
Leading Lights Leading Lights A two-light structure with light fixtures. A front light is installed at a lower height while a rear light is installed at a higher height. It is built on land, in a line extending from the navigating route to indicate difficult channels, harbors or port gates with a narrow entrance
Direction Lights Direction Lights A structure with projecting lights of three different colors - green, white, and red - built on a site on land in a line extending from the navigating route to indicate difficult channels, harbors or port gates with a narrow entrance. The vessels may navigate through the safe zone lit in white.
Light Buoy Light Buoy Light buoys are floating at sea to indicate reefs, shoals and limits of the channel. If it has light fixtures, it is a lighted buoy, if not, it is an unlighted buoy

Shape Aids to Navigation : indicating the location with shapes or colors during daytime

Basic Requirements

  • This system employs a simple arrangement of shapes and colors to mark a location during daytime

Types of Shape Aids to Navigation

Types of Visual Aids to Navigation
Type Description
Beacon Beacon A boundary mark indicating reefs or uncovered rocks. As it is built underwater separately, selection of location and design should be good enough to endure waves, wind pressure and tidal currents. In particular, clearing markers are to help avoid reefs or other dangers
Buoy Buoy A float moored in water which is difficult to navigate where fixed marks are not available. It also plays a role of an inducer. Buoys with lights are referred to as lighted buoys
Leading mark Leading mark Aid that indicates difficult channels and harbors with a narrow entrance, guiding vessels to navigable channels as a direction mark They are built on land in a line extending from the navigating route composed of front and rear landmarks, or more than two landmarks

Sound Aids to Navigation : indicating a location by generating sounds when visibility is restricted by fog, snow, rain, etc.

Basic Requirements

  • Sound aids to navigation inform their location to vessels with sounds generated by sound waves.
    Machines that generate sound waves for this purpose are fog signals
  • Fog signals are built in areas or harbors of often restricted visibility by fog, snow, sunset, heavy rain or haze. Under these conditions, they are operated day and night. They have a relatively short range, as they are operated by sound. Moreover, the range and direction of sound vary according to weather or sea conditions

Types of Shape Aids to Navigation

Types of Shape Aids to Navigation
Type Description
Air Siren Air Siren Sounding a siren blast through compressed air. They are attached to a lighthouse in foggy coastal areas, detect fog, and make sounds automatically under foggy conditions to inform of their locations to nearby vessels.
Electrical horn Electrical horn Sound aid that produces a siren using low frequency vibrations
Motor Siren Motor Siren Sound aid that produces a siren using motors

Radio Navigation : Using it as indicators for navigation by taking advantage of the various characteristics of radio waves

Basic Requirements

  • Every indicator with the features of radio waves such as straight, constant velocity or reflexibility for vessels or airplanes is called radio navigation or radio-beacon. As it makes use of radio waves, it has the advantages of availability under any conditions and range across a broad area.

Types of Shape Aids to Navigation

Types of Shape Aids to Navigation
Type Description
Air Siren Air Siren DGPS is an acronym for the Differential Global Positioning System, and it is a system emitting G1D modulated to MSK with Radio Beacon signal (A2, A) of 283~325kHz on medium wave by more accurately correcting Localization Errors of GPS using 24 satellites (21+3 reserves), which has 10m degree and 100m effective range.
Electrical horn Electrical horn A Racon is a radar transponder commonly used to show the location of a ship on its radar screen with a Morse bright-line spectrum by emitting non-directional waves, 24 hours a day. It contributes to the safe operations of a ship in dense fog or bad weather.
Motor Siren Motor Siren LORAN (Long Range Navigation) is a long-range radio navigation system to measure the location of a ship by using hyperbolic navigation. Loran-A and Loran-C are commonly used systems.

Special Purpose Aids to Navigation : Sending various navigation information including vessel traffic or tidal current directions with radio waves or shapes to navigational vessels during day or night in narrow straits or waterways.

  • VTS : Designed to guide vessels for safe navigation by installing radar and CCTVs in waters like port entrances or channels, or narrow channels
  • Tidal Current Signal Station : A large screen signal system indicating strength and direction of tidal current to navigational vessels sailing in strong waters like harbor entrances or channels, or narrow channels
  • Weather signal box : Designed to give necessary information like special weather reports to navigational vessels
  • Radar Beacon : A radar response unit to show the location of a transmitting station with Morse-code on a vessel's radar screen

IT based maritime traffic system

Types of Shape Aids to Navigation
Remote monitoring systemRemote monitoring system Maritime weather signal systemMaritime weather signal system
Current signal system

Current signal system
A to N AIS/navigational
aid automatic identification system
A to N AIS/navigational aid automatic identification system