🔍 Key Concepts

• Electronic Plotting Aid (EPA) capabilities and limitations compared to ARPA (Automatic Radar Plotting Aid) • Typical collision-avoidance information: CPA (Closest Point of Approach) and TCPA (Time to CPA) • How target trails and number of tracked targets help with assessing risk of collision

💭 Think About

• Think about what information a watch officer needs from an EPA to quickly judge the risk of collision with another vessel. • Consider whether an EPA is usually limited to only one of these functions, or if it is normally designed to bundle several collision-avoidance tools together. • Ask yourself: which of these listed functions are clearly related to evaluating other vessels’ movements and potential close-quarters situations?

✅ Before You Answer

• Verify whether TCPA is a standard output of electronic plotting systems used for collision avoidance. • Check if target trails are commonly associated with displaying the past motion of targets on radar/EPA displays. • Confirm whether there is any reason an EPA would be restricted to plotting only one of these functions rather than combining them.