The image presents different water depth limitations when navigating with an ENC in ECDIS. Mariners can set an advance time warning to indicate when the vessel is approaching the set limits. The following limits can be set:

Safety depth:

The depth defined by the mariner, e.g. the ship's draft plus underkeel clearance, to be used by the ECDIS to emphasize soundings on the display equal to or less than this value.

Safety contour:

The contour related to the own ship selected by the mariner from the contours provided for in the SENC, to be used by ECDIS to distinguish on the display between the safe and the unsafe water, and for generating anti-grounding alarm.

If an ENC does not offer a depth for the selected water depth, the next deeper option will be selected instead.

• Incorrect Contour Settings

  

   Wrong contour settings

  Incorrect Deep Contour and Shallow Contour settings may cause problems with alarms based on those settings. Additionally, the chart presentation of the ECDIS system is in that case insufficient. 

• Correct Contour Settings

  

   Correct Contour settings

  Following settings are defined to generate an appropriate alarm and a most convenient chart presentation. 

   

   

  Draught: 12 m

  Deep Contour: 25 m

  Safety Contour: 15 m

  Shallow Water: 10 m