From OpenStreetMap Wiki
|Status:||Draft (under way)|
|Definition:||An area of the sea floor which nears the sea surface (literally, becomes shallow) and can lie completely below it or be exposed at low tide.|
|Rendered as:||dotted line|
Alternatively, it can be described as tidal sand spit, although the latter is generally not tidally washed. Often, but not always, breaks waves over its top and can be a hazard to navigation, as in the famous wikipedia:Nantucket Shoals.
- man_made=shoal - perhaps for artificial surf breaks