Maritime Training & STCW Courses › Radar Observer
Checked against 46 CFR 11.480 and 15.815 · October 2026
The short answer
- Radar Observer is a national endorsement on your Merchant Mariner Credential (MMC) showing you're trained to use radar for collision avoidance and navigation.
- It's required for deck officers on radar-equipped inspected vessels of 300 GRT or more, for pilots on radar-equipped vessels of 300 GRT or more, and for masters and mates of radar-equipped towing vessels 26 feet or longer.
- There are three versions: Unlimited, Inland Waters and GIWW, and Rivers.
- You get it by completing a Coast Guard-approved course and submitting the certificate. It's then valid until your MMC expires.
What is it?
Radar Observer is an endorsement the Coast Guard adds to your MMC after you complete an approved radar course. The course certificate is the evidence; the endorsement is the qualification. Course vs. endorsement →
| Version | Valid on |
|---|---|
| Radar Observer-Unlimited | All waters |
| Radar Observer-Inland Waters and GIWW | Inland navigable waters and the Gulf Intracoastal Waterway, not the Great Lakes |
| Radar Observer-Rivers | Rivers, canals and similar waters designated by the local Coast Guard Officer in Charge, Marine Inspection (OCMI) |
Source: 46 CFR 11.480
Who needs it?
- Deck officers, including the master, in the required complement of inspected vessels of 300 GRT or more that carry radar.
- Pilots serving under federal law on radar-equipped vessels of 300 GRT or more.
- Masters and mates of towing vessels 8 meters (26 feet) or longer that are fitted with radar. 46 CFR 15.815 Towing careers →
Mates working toward an unlimited license will need it, and employers on smaller vessels often ask for it even when the regulation doesn't.
Who may not need it?
- Unlicensed ratings, such as ABs and ordinary seafarers. The requirement applies to officers and pilots.
- Masters of smaller vessels that aren't towing vessels, such as many six-pack and small passenger vessel operators under 300 GRT, unless the employer requires it.
Choose the version that matches the waters you'll work. A Rivers endorsement won't cover you offshore.
Where it fits in your career
AB to Third Mate → · The Deck Officer Ladder →
Requirements
- Complete the Coast Guard-approved Radar Observer course for the version you need, and pass its practical demonstration.
- Submit the course certificate to the Coast Guard. 46 CFR 11.480
The course
An approved Radar Observer course covers how radar works, its limitations and errors, plotting other vessels' courses and closest points of approach, and applying the Rules of the Road in restricted visibility, with hands-on simulator work. Inland and Rivers courses focus on the waters they cover. Check that the course is approved for the exact version you need. How to check a course →
What happens after the course?
- Keep the course certificate.
- Submit it to the National Maritime Center (NMC), usually with an officer endorsement application or renewal.
- The endorsement is valid until your MMC expires.
- To keep it at renewal, you'll need one of: an approved refresher course; at least 1 year of relevant sea service in the last 5 years in a position that routinely uses radar for navigation; or one of the other ways allowed under 46 CFR 10.227(e)(1)(v). Without that evidence, it won't appear on your renewed MMC. 46 CFR 11.480 Renewal & Continuity →
Common mistakes
- Taking Rivers or Inland when you'll need Unlimited. Match the endorsement to where you'll sail.
- Assuming radar sea time counts automatically. The renewal route needs service in a position that routinely uses radar for navigation, and your letters should say so.
- Confusing Radar Observer with STCW radar or ARPA training. They're separate requirements.
- Letting it drop off at renewal. If you can't show the sea service, take the refresher before you file.
Get the version for the water you want to work, not the one that's convenient this month. And when you're sailing, ask that your sea-service letters mention bridge watches using radar. It can save you a refresher course at renewal.
Official sources
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