🔍 Key Concepts

• Power-driven vessel underway vs towing vessel light requirements • Which light(s) are visible from astern only per the Navigation Rules • The difference between sternlight, towing light, and masthead lights

💭 Think About

• First decide: if a tug is not actually towing, is it treated as a special towing vessel or just a normal power-driven vessel for lights? • Think about which light is specifically defined to show to other vessels coming up from more than 22.5° abaft the beam (from behind). What color and how many of those are required? • Ask yourself: when are yellow lights aft required, and what condition on the tow must exist for that to apply?

✅ Before You Answer

• Verify the definition and color of a sternlight in the Navigation Rules (Rule 21). • Check Rule 23 for power-driven vessels underway and note what is required aft. • Confirm when a towing light (yellow) is required aft (Rule 24) and whether that applies when the tug is not towing.