Which bathymetric feature is shown only on Provisional-Edition maps?

Which bathymetric feature is shown only on Provisional-Edition maps?

• A. Sunken rock
• B. Channel
• C. Foreshore flat
• D. Exposed wreck

Answer: (A)

Provisional edition charts are used to publish new or uncertain information that hasn’t yet been fully verified for the standard chart. They highlight hazards and features that could affect safety but aren’t confirmed enough to upgrade the main map. A sunken rock fits this role because it’s a submerged hazard that can be difficult to detect and may be identified after a survey or new data comes in. Placing it on a provisional chart warns mariners to exercise extra caution until the position and existence are confirmed for the official edition. In contrast, channels and foreshore flats are more routine chart features that rely on established data, and an exposed wreck, once verified, would typically appear on the standard chart rather than being confined to provisional editions.