Which vessels are required to carry ARPA equipment?

• A. All vessels
• B. Vessels 10,000 gross tons or more EXCEPT public vessels, AND tank vessels 10,000 gross tons or more operating in navigable waters
• C. Vessels operating in restricted waters
• D. Only public vessels

Answer: (B)

ARPA is meant for ships where advanced radar plotting is most needed to manage complex, high-traffic navigation and prevent collisions. The regulation targets large vessels, requiring ARPA on ships of 10,000 gross tons or more, with two key carve-outs: public (government) vessels are exempt, and tank vessels of 10,000 gross tons or more operating in navigable waters are included. This combination ensures that the ships with the greatest potential risk and traffic—large merchant and fuel/cargo tankers in busy waterways—are equipped to track multiple targets and calculate collision threats automatically. Smaller vessels, or those operating only in restricted waters, don’t fall under this ARPA requirement, and public vessels are not required to carry it.