7.2 Maritime Navigation, Buoys, and Rules of the Road
Key Takeaways
- In the IALA Region B system, the 'Red Right Returning' rule dictates that red buoys should be kept on the starboard side when returning from the sea.
- The give-way vessel must take early and substantial action to avoid a collision, while the stand-on vessel must maintain its course and speed.
- In a crossing situation between two power-driven vessels, the vessel that has the other on its starboard side is the give-way vessel.
- A power-driven vessel must generally give way to sailing vessels, vessels engaged in fishing, and vessels with restricted maneuverability.
Introduction to Maritime Navigation
Navigating the world's oceans requires a comprehensive understanding of aids to navigation and the "Rules of the Road." Just as traffic lights and lane markings guide automobiles, an international system of buoys, lights, and regulations ensures the safe passage of vessels at sea. For aviation candidates, grasping these concepts is vital, as maritime operations frequently intersect with naval aviation.
Aids to Navigation: The Buoyage System
The International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA) governs maritime buoyage systems. The United States follows the IALA Region B system.
Lateral System and the "Red Right Returning" Rule
The lateral system indicates the edges of safe water areas. In IALA Region B (which includes the Americas, Japan, South Korea, and the Philippines), a fundamental mnemonic is "Red Right Returning." This means that when a vessel is returning from the open sea (entering a harbor or proceeding upstream), the red buoys should be kept on the starboard (right) side of the vessel, and green buoys on the port (left) side.
- Red Buoys: Typically nun buoys (conical shape), featuring even numbers. At night, they may display a red light.
- Green Buoys: Typically can buoys (cylindrical shape), featuring odd numbers. At night, they may display a green light.
- Daymarks: Fixed signs attached to structures in the water, functioning similarly to buoys. Red triangles correspond to red buoys, and green squares correspond to green buoys.
The Cardinal System
While the lateral system depends on the direction of travel, the cardinal system is absolute, based on the compass. Cardinal marks indicate where the deepest and safest water lies relative to the mark. For example, a North Cardinal mark indicates that safe water is to the north of the mark. These are heavily used in IALA Region A (Europe, Africa, Australia, and most of Asia) and are characterized by black and yellow horizontal bands and specific topmarks (two black cones).
Navigation Rules: The "Rules of the Road"
The International Regulations for Preventing Collisions at Sea (COLREGs) act as the maritime equivalent of traffic laws. They dictate which vessel has the "right of way" (the stand-on vessel) and which must alter course (the give-way vessel).
Basic Definitions
- Stand-on Vessel: The vessel that must maintain its course and speed. This predictability allows the other vessel to maneuver safely around it.
- Give-way Vessel: The vessel that must take early and substantial action to keep clear of the stand-on vessel.
Determining the Right of Way
A general hierarchy exists for determining which vessel is the give-way vessel, based on maneuverability. A highly maneuverable power-driven vessel must generally give way to vessels with restricted maneuverability. The hierarchy, from most privileged (stand-on) to least privileged (give-way), is:
- Vessel Not Under Command (NUC): A vessel that, through exceptional circumstances (e.g., engine failure), cannot maneuver.
- Vessel Restricted in her Ability to Maneuver (RAM): A vessel engaged in work that restricts maneuverability (e.g., dredging, laying cable).
- Vessel Constrained by Draft: (Only applies under International Rules, not US Inland Rules). A vessel whose draft restricts her to a narrow channel.
- Vessel Engaged in Fishing: Specifically commercial fishing with nets or trawls, not recreational fishing.
- Sailing Vessel: A vessel propelled solely by wind. If a sailboat has its engine running, it is considered a power-driven vessel.
- Power-Driven Vessel: Any vessel propelled by machinery.
- Seaplanes: Generally must keep well clear of all vessels.
Common Encounter Situations
When two power-driven vessels encounter each other, specific rules apply:
- Overtaking: A vessel approaching another from more than 22.5 degrees abaft the beam (from behind) is the overtaking vessel. The overtaking vessel is always the give-way vessel and must steer clear of the vessel being overtaken.
- Head-On: When two power-driven vessels are meeting on reciprocal or nearly reciprocal courses so as to involve risk of collision, both vessels are required to alter their course to starboard (right), passing port-to-port.
- Crossing: When two power-driven vessels are crossing courses, the vessel which has the other on her own starboard side is the give-way vessel. Conversely, if you see a vessel on your port side, you are the stand-on vessel.
Sound and Light Signals
Communication between vessels is vital for clarifying intentions, especially in reduced visibility or close-quarters situations.
- One Short Blast: Indicates "I intend to leave you on my port side" (altering course to starboard).
- Two Short Blasts: Indicates "I intend to leave you on my starboard side" (altering course to port).
- Three Short Blasts: Indicates "I am operating astern propulsion" (backing up).
- Five or More Short, Rapid Blasts: The danger or doubt signal. Used when a vessel does not understand the intentions of another, or believes the other vessel's actions are insufficient to avoid a collision.
During periods of restricted visibility (like fog), vessels must sound specific signals at regular intervals. A power-driven vessel making way through the water sounds one prolonged blast every two minutes, while a sailing vessel sounds one prolonged blast followed by two short blasts every two minutes. Mastery of these rules ensures that the vast, seemingly unregulated oceans remain organized and safe for all mariners.
Navigation Lights
To safely navigate at night, mariners rely on a standardized system of navigation lights that indicate a vessel's type, size, and orientation.
- Masthead Light: A white light placed over the fore and aft centerline of the vessel, showing an unbroken light over an arc of the horizon of 225 degrees, fixed to show from right ahead to 22.5 degrees abaft the beam on either side.
- Sidelights: A green light on the starboard side and a red light on the port side, each showing an unbroken light over an arc of 112.5 degrees.
- Sternlight: A white light placed as nearly as practicable at the stern, showing an unbroken light over an arc of 135 degrees. By observing the combination of these lights, a mariner can instantly determine the heading of an approaching vessel and apply the appropriate Rules of the Road in total darkness.
Under the International Regulations for Preventing Collisions at Sea, what action should two power-driven vessels take when meeting head-on?
According to the general hierarchy of the Rules of the Road, which of the following vessels is considered the most privileged (stand-on) and requires all other listed vessels to give way?