🔍 Key Concepts

• Rule 35 – Sound signals in restricted visibility (fog signals) • Which vessel types are grouped together with a vessel not under command for the same whistle signal • Difference between fog signals for a towed vessel, a sailing vessel, and a vessel aground

💭 Think About

• First, recall the exact fog whistle pattern used by a vessel not under command (number and order of prolonged vs. short blasts). Then ask: which other vessels use that same pattern under Rule 35? • Think about how the Rules group vessels: some ‘special’ vessels (NUC, restricted in ability to maneuver, constrained by draft, fishing, towing, sailing) share one pattern, while a towed vessel and a vessel aground each have their own distinct patterns. • Ask yourself: in fog, does a sailing vessel underway sound the same as a power-driven vessel, or is it included in the special group with NUC and RAM for a different pattern?

✅ Before You Answer

• Verify from Rule 35 (International) which vessels use: one prolonged blast followed by two short blasts. • Check separately what signal a towed vessel (or last vessel of a tow if manned) must sound – note how many short blasts it uses. • Confirm that a vessel aground uses primarily bell/gong signals (with some optional whistle patterns), not the same standard whistle-only pattern as a vessel not under command.