Navigation General · Light Characteristics
The notation 'Mo(A)' on a chart or Light List indicates a light that:
- AShows alternating red and white sectors
- BTransmits Morse code letter A (dot-dash) in flashes✓ Correct
- CIs a quick-flashing amber light
- DShows a group of flashes equal to 'A' on the phonetic alphabet
Explanation
Mo(A) means a Morse code light showing the letter A: one short flash followed by one long flash, repeated. Safe water marks commonly use Mo(A).
Authority: 33 CFR 62 (U.S. ATON System)
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