Vessels required to have an Automatic Radar...

🔍 Key Concepts

• Automatic Radar Plotting Aid (ARPA) performance standards (what ARPA is specifically designed to measure and display) • Difference between own ship data (heading, speed input) and extra navigation systems like ECDIS and AIS • Meaning of speed through the water vs speed over the ground and why radar collision-avoidance might need one or the other

💭 Think About

• Ask yourself: What minimum information must ARPA receive/indicate in order to calculate and display target courses, speeds, closest point of approach (CPA), and time to CPA (TCPA)? • Which options describe information that is essential for radar collision avoidance, and which describe information from separate systems (like ECDIS or AIS) that are not part of the basic ARPA requirement? • Consider which choice matches the mandatory inputs/indications for ARPA as set out in IMO performance standards, rather than optional or integrated features found on modern bridges.

✅ Before You Answer

• Verify which option directly supports relative motion and CPA/TCPA calculations done by ARPA. • Check whether ECDIS tracks or AIS data are actually part of the ARPA requirement, or just common integrations on newer equipment. • Confirm whether ARPA must indicate the vessel’s speed, and if so, whether it refers to speed over the ground or through the water in the regulations/performance standards.

Vessels required to have an Automatic Radar Plotting Aid must have a device to indicate which of the following?

The vessel's current position

Speed of the vessel over the ground or through the water

An ECDIS generated trackline

AIS information of vessels in the vicinity

🔍 Key Concepts

💭 Think About

✅ Before You Answer