Sperry Marine Visionmaster FT ECDIS, User Manual

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Charts ECDIS User Guide
4-46 65900012
Chart Depths/Heights
The chart depths/heights window enables you to
change the default settings of own ship's safety
depth/height and contour, and shallow/deep
shading contours.
On a multi-node system any changes made in
Chart Depths/Heights are distributed and
persisted across all nodes.
WARNING!
CHANGES MADE TO SHALLOW/DEEP SHADING VALUES ARE
HIGHLIGHTED ON VECTOR CHARTS ONLY (E.G. C-MAP OR S-57).
RASTER CONTOUR AREAS CANNOT BE ADJUSTED IN THIS WAY.
Ship Safety
The Ship Safety area includes depth, contour and height safety settings for
own ship.
The safety depth is the minimum depth required by an underwater object
for own ship to pass over safely. The minimum depth is the distance from
the water surface to bottom of own ship's keel, plus a safety buffer against
variations in the water level from the time the water was charted to the
present time.
The safety contour is the minimum contour depth required for own ship to
pass over safely. Safety checking uses the given value to determine
whether underwater objects are to be considered Objects of Concern. An
alarm is raised if own ship passes over a contour depth less than the given
value.
The safety height is the minimum distance required by an overhead
obstruction for own ship to pass under safely. The minimum height is the
distance from the surface of the charted water to the lowest point of the
overhead obstruction.
The default values for Ship Safety settings are 30 metres.
If the safety depth is set at a value less than the configured value of own
ship's maximum draft a
Safety Depth Shallow Caution is displayed.
If the safety height is set at a value less than the configured value of own
ship's height a
Safety Height Low Caution is displayed.