Radar and ARPA

Radar Observer Information

The Navigation Rules (Rules of the Road) requires that the vessel operator to understand the operation of radar for determining risk of collision. Having a Radar Observer Endorsement documents that you have received training in the application of radar for both collision avoidance and navigation.

A Radar Observer Endorsement can be added to any Merchant Mariner Credential and is required for deck officer endorsements greater than 200 tons and the STCW endorsement for Officer In Charge of a Navigation Watch (OICNW).

All radar observer endorsements are valid for five years and require a demonstration of collision avoidance plotting skills to renew. Mariners requiring a radar observer endorsement must keep their original or renewal course completion certificates with them as poof of holding a valid radar observer endorsement.

To qualify for an original Radar Observer Endorsement the applicant must received approved training in the use and operation of radar equipment. This training is provided in two parts:

  • Radar Theory: this includes instruction on the theory, setup, and operation of radar; and the application of radar for navigation and to determine risk of collision.
  • Rapid Radar Plotting: this includes instruction in manual plotting techniques to determine risk of collision and action to avoid collision with a minimum CPA.

To qualify for a renewal of a Radar Observer endorsement the mariner must demonstrate the ability to determine the range and bearing of multiple contacts on a radar or radar simulator and demonstrate an understanding of relative motion, including the action required to pass a contact at a safe distance.

Automatic Radar Plotting Aids (ARPA) Information

ARPA is a negative STCW endorsement, meaning that without an ARPA training certificate your MMC will be endorsement as “not valid for ARPA equipped vessels. After presenting a valid ARPA training certificate the National Maritime Center will remove the negative endorsement from the mariner’s MMC.

To qualify for an ARPA course the mariner must have a valid Radar Observer Unlimited endorsement. An ARPA class covers the theory, development, and application of ARPA as it applies to the application of the International COLREGS (Rules of the Road).