The International Regulations for Preventing Collisions at Sea (IRPCS) include provisions for the use of shapes and sounds as visual and audible signals to communicate intentions and warnings between vessels. These signals are crucial for maintaining safe navigation and avoiding collisions, especially in situations where visibility may be limited. Let’s explore the use of shapes and sounds as outlined in the IRPCS:
Shapes:
- Anchored Vessel: When a vessel is at anchor, it must display a black ball shape during the day to indicate its status to other vessels.
- Vessel Not Under Command: A vessel that is unable to maneuver, such as due to mechanical failure or being aground, must display two black balls vertically during the day.
- Vessel Restricted in its Ability to Maneuver: A vessel that is restricted in its ability to maneuver, such as due to its work or operation, must display three black balls vertically during the day.
- Vessel Engaged in Fishing: A vessel engaged in fishing must display two black cones, apexes together, during the day to indicate its activity.
Sounds:
- Short Blast: A short blast on the horn or whistle, which lasts for about one second, is used to indicate intentions such as passing on the starboard (right) side.
- Prolonged Blast: A prolonged blast, which lasts for about four to six seconds, is used as a warning signal to indicate danger or an imminent risk of collision.
- Rapid Succession of Short Blasts: A rapid succession of short blasts is used to signal the intention to overtake another vessel.
- One Prolonged Blast Followed by Two Short Blasts: This sound signal is used by a vessel leaving a dock or berth to indicate its movement.
It is essential for mariners to understand and recognize these shapes and sounds to effectively communicate and interpret the intentions of other vessels. This helps promote safe navigation, especially in situations where visibility may be reduced due to factors such as fog, darkness, or heavy rain.
Remember, the use of shapes and sounds as outlined in the IRPCS should be done in accordance with the specific rules and guidelines provided. Familiarize yourself with these signals and be prepared to use them appropriately to ensure clear communication and prevent collisions while at sea.