Mean Sea Level (MSL) is the zero-level datum used for depth readings. Which statement best describes MSL?

• A. The zero-level datum used for length measurements.
• B. The reference height for the tide-forecast charts only in rivers.
• C. The zero-level datum used for depth readings; depths may be referenced to MSL or MLLW depending on chart.
• D. The mean seasonal water height.

Answer: (C)