Are there differences in how fog or restricted visibility signals are used on inland waterways compared to international rules?

• A. No; they are identical.
• B. Fog signals are banned inland.
• C. Inland signals may differ in types and procedures for fog, compared to international rules.
• D. Inland waterways use only verbal signals in fog.

Answer: (C)

Fog signals are used to communicate in restricted visibility, but the exact signals and procedures can differ between international rules and inland regulations. The international rules provide a standard set of sound signals for restricted visibility, but inland waterways have their own Navigation Rules that may specify different types of signals or different ways and times to use them. This reflects the local navigation environment, equipment, and traffic patterns inland, so mariners must follow the inland rules when operating there, rather than assuming a one-to-one match with international rules. The other options aren’t correct because fog signals are indeed used inland, they are not banned, and signals aren’t limited to verbal messages—sound signals (and sometimes other means) are still used inland, though they may differ from international standards.