🔍 Key Concepts

• How charted shorelines are defined in standard hydrographic practice • The difference between high water and low water tidal datums • Which tidal level is safest for showing dangers close to land on a chart

💭 Think About

• Ask yourself: If the shoreline were drawn at low water, what would happen to features that are only covered at high tide? • Consider which tidal level best represents where land is usually dry and visible to a mariner approaching the coast. • Think about how chartmakers ensure that rocks and shoals near the coast are portrayed in a way that avoids giving a false sense of clearance.

✅ Before You Answer

• Review which tidal datum is typically used for soundings versus which is used to depict shoreline and drying heights. • Check your memory of how the U.S. Coast Pilot or chart marginal notes describe charted datums. • Verify which option represents a level that is above most tides, not in the middle or at the lowest state of tide.