USCG-RADAR-L3.1

Relative motion plotting: the method

USCG-RADAR-M3 · Relative Motion Plotting · USCG-RADAR-M3-A The e-r-m method and two worked plots, from CPA and TCPA to avoiding action and ARPA checks.

Every radar plot is a **vector triangle**. Learn one notation, the **e-r-m triangle** of Pub. 1310, and use it every time.

AI-drafted catalogue content pending SME review. Radar Observer renewal by sea service depends on the NMC accepting that the position routinely used radar, and the carriage rule turns on inspected status and GRT; verify with the National Maritime Center and your approved course provider before relying on either.