AhaBulbStuff Everyone Should Know
AhaBulb: Stuff Everyone Should Know · ahabulb.com/boat-sailboat-running-lights

A sailboat moving under sail alone at night shows which lights?

Sidelights and a sternlight.

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  1. Sidelights and a sternlight ✔
  2. A masthead light and a sternlight
  3. One red all-round light

Why: Inland Rule 25 says a sailing vessel underway shows sidelights and a sternlight. Unlike a power-driven vessel under Rule 23, it shows no white masthead light.

Huh, didn't know that: Sailboats under 20 meters may combine those lights into one lantern at or near the top of the mast.

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What did the mermaid wear to math class? An algae-bra.
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References

Answer: Sidelights and a sternlight. Inland Rule 25 says a sailing vessel underway shows sidelights and a sternlight. Unlike a power-driven vessel under Rule 23, it shows no white masthead light.

  1. 33 CFR 83.25 Sailing vessels underway and vessels under oars, Inland Rule 25 (eCFR) www.ecfr.gov/current/title-33/section-83.25
    A sailing vessel underway shall exhibit: (i) Sidelights; and (ii) A sternlight.
    Checked 2026-10-08.

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Boating & WaterWhen must recreational boats show their navigation lights?Boating & WaterAt night you see only another boat's white sternlight, no red or green. What situation is this?Boating & WaterA boat under 50 meters anchored at night may show what single light?

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