Comparisons
Maritime study — side-by-side comparisons
When two concepts look identical until you look closer, a side-by-side beats a long article. These are the comparisons we get the most exam questions about — IALA Region A vs Region B, COLREG head-on vs crossing, NUC vs RAM, COLREG vs US Inland Rules, and the Spanish PER vs PNB.
IALA Region A vs Region B — what actually changes
IALA Region A vs Region B in one page: which countries use which, what changes (only the lateral marks), the "red right returning" memory aid, and how to never confuse them on an exam.
Open comparisonHead-on (Rule 14) vs Crossing (Rule 15) — telling them apart
When is it head-on, when is it crossing? Rule 14 vs Rule 15 side-by-side with the exact angle thresholds, who turns where, what the lights tell you, and the trap examiners use to swap them.
Open comparisonNUC vs RAM — the two reds that everyone mixes up
Two red lights or red-white-red? NUC vs RAM compared in one table: definitions, lights, day shapes, who gives way and the exam traps that swap them. Free reference.
Open comparisonCOLREG vs US Inland Rules — what changes inside the demarcation line
Inside the COLREG Demarcation Lines, the US Inland Navigation Rules apply, not COLREGs. Side-by-side of every difference USCG exams test: yellow flashing lights, whistle conventions, Western Rivers, special anchorage areas.
Open comparison