Which mark sits on or close to a small hazard with navigable water around it?
Short answer
An isolated danger mark, with the chart used to resolve the danger's extent and passing distance
An isolated danger mark is placed on, moored above or close to a small isolated danger with navigable water around it. That definition does not make close passage safe: the chart and publications define the danger's extent, depth and suitable clearance. Use the black-and-red body, two black spheres and two-flash light together, and revise Safe Water and Isolated Danger.
Sources and scope
Reviewed by Richard Moore on . This answer is scoped to iala region a unless the answer says otherwise; check the current chart, publication, local rules and official operational guidance before acting afloat.
Quick check
Which mark sits on or close to a small hazard with navigable water around it?