- If restricted visibility encountered or suspected.
- If traffic conditions or the movements of other ships are causing concern.
- If difficulty is experienced in maintaining course.
- On failure to sight land, a navigation mark or to obtain soundings by the expected time.
- If unexpectedly sighted land or a navigation mark or change in sounding occurs.
- On breakdown of main engines, steering gear or any essential nav equipments, alarms or indicator.
- If radio equipment malfunctions.
- In heavy wx (weather) if any doubt about the possibility of wx damage.
- If the ship meets any hazard to navigation, such as ice or derelict.
- If any other emergency or if in any doubt.
