All the parameters below must be clearly defined in the Company SMS. Below is for guidance only.
Safety Depth:
Usually Safety Depth = Max draft + CATZOC or UKC requirement of the company, whichever is higher.
Soundings less than Safety Depth is highlighted in Black and bold letters. Those more than safety depth are faded out. Safety depth does not trigger an alarm.
Safety Contour:
Usually Safety Depth = Safety contour
Refer to Company Navigation procedures. There must be an alarm if the vessel crosses a Safety contour. There must be a Procedure or RA for it.
Shallow contour:
Shallow contour highlights the area of depths below the Shallow contour setting and zero. NO ALARM.
Deep contour:
Deep contour highlights the area of depths below the Deep contour setting and below. Those more than Deep contour setting are white. NO ALARM
Important Note:
It is important to understand that during the voyage, based on the change of depths the Safety settings will change. This must be calculated leg by leg and mentioned in the passage plan. It depends on the Company's UKC policy and ECDIS policy.