🔍 Key Concepts

• Inland Navigation Rules – sound signals for locks and bridges (not the standard meeting/crossing/overtaking signals) • Difference between long blast and short blast durations • How mariners request single vs. double lockage by sound signal

💭 Think About

• Think about which signals you normally use for meeting, crossing, or overtaking situations, and consider whether this lockage signal is one of those or a special-purpose signal. • Ask yourself: does a ‘single lockage’ mean you want one chamber cycle for just your vessel (or group), and would that likely be a simple, easily distinguished pattern? • Consider how a lock operator needs to distinguish between a request for lockage and other routine maneuvering signals in the area.

✅ Before You Answer

• Verify in the Inland sound signal regulations that there is a specific pattern for requesting lockage, separate from maneuvering signals. • Confirm the duration difference: a long blast is typically 4–6 seconds, a short blast about 1 second. • Check which of the options is not commonly used as a meeting/crossing/overtaking signal, making it more suitable as a special lock-request signal.