Ship conflict warning from stand-on ship perspective

Ship conflict warning is a plausible way to reduce the ship collision probability by alerting the ship of a conflict hazard timely. However, there is a lack of method that focuses on alerting the stand-on ship to compensate the give-way ship unawareness of or inactive response to a risky situation that requires immediate action. Therefore, this article aims to propose a conflict warning method from the stand-on ship perspective to trigger the stand-on ship’s involvement in the conflict elimination by quantifying the terms of the COLREGs regarding the stand-on ship’s responsibility for conflict elimination. The conflict severity is divided into 8 classes by conflict evolution analysis, according to the give-way ship’s action performance, the stand-on ship’s maneuverability and the rules in COLREGs. These 8 subdivided conflict classes are linked with the 5 stages of the encounter process to support the stand-on ship to accurately understand the current conflict severity and her corresponding action responsibilities. Finally, several typical encounter scenarios are designed and the own ship is set in the stand-on position to demonstrate the feasibility of this proposed conflict warning method. The results show that the proposed conflict warning method from the stand-on ship perspective can identify the give-way ship’s action intention, and accurately assess the conflict evolution to clarify the conflict severity currently and the corresponding obligation of own ship in the stand-on position, which contributes to the collision probability reduction.