No-go area

A no-go area is a zone marked on the passage plan that the vessel must not enter at the planned state of tide, defined by charted depths shallower than the ship’s draft plus required under-keel clearance, plus a safety margin. The navigator shades these areas, shoals, rocks, restricted zones, during the appraisal and planning stages so the safe water and the planned track stand out at a glance, and parallel-index lines and clearing bearings are set to keep the ship clear. Defining no-go areas is part of voyage planning under SOLAS Chapter V Regulation 34.