Sports

What is safety depth and safety contour?

By: Gautam MandalUpdated: January 06, 2021

Categories

Site Statistics

  • Questions
    94,481
  • Answers
    1,984,101
  • Categories
    21
  • Last Updated
    September 26, 2022
Use of the Safety Depth and the Safety Contour in ECDIS
Safety Contour: A specific depth contour set by ECDIS. It demarks the boundary between “safe-water” and shallow water with an extra wide isoline and is used to give an alarm if the ship, within a time specified by the mariner, is going to cross the safety contour.

Similarly, what is the difference between safety contour and safety depth?

Safety depth is normally the ship's draft + squat. Some soundings on the shoaler side of the safety contour will be gray because they are deeper than the safety depth set by the mariner, although shoaler than the safety contour selected by ECDIS. The depths below safety contour may not always be non-navigable.

Additionally, how is the safety contour displayed in the chart area?

The ECDIS will display 10 meter contour line as the shallow contour. If 10 meter contour is not available, it will take next contour as the shallow contour for the vessel. The shallow contour lets the navigator know that between 0 meter depth and the shallow contour, the area is not navigable at all.

What is safety depth?

Safety Depth: Value set by the mariner that is used by ECDIS to portray soundings as black if they are equal to or shoaler than the value and gray if they are deeper. Safety Contour: A specific depth contour set by ECDIS.

How is Catzoc calculated?

  1. You can download the pdf version of the CATZOC table here.
  2. SAFETY DEPTH = MAX DRAFT + REQUIRED UKC.
  3. ZOC Allowance (A1) = 0.5 + 0.01 × Depth.
  4. ZOC Allowance (A1) = 0.5 + 0.01 × 18.8 = 0.688 ≈ 0.7 m.
  5. ZOC Allowance (C) = 2.0 + 0.05 × 17.3 = 2.865 ≈ 2.9 m.

Related

How do you calculate safety contour?

Shallow Contour: Indicates the depth below a vessel could run aground and it is equal to vessel's maximum static draft. Safety Depth = Maximum Draft(static) + UKC (Company's Policy) + Squat(Maximum) - Height of Tide. Safety Contour: Is calculated same as per Safety depth AND activates ALARM when depth is less.

What is static and dynamic draft?

The Static Draft is the draft when the vessel is not making way or subject to sea and swell influences, i.e. the maximum draft the vessel has loaded to. There is no sea, swell, or appreciable list, so the dynamic draught is 11.8m.

What is Scamin?

SCAMIN is an abbreviation of Scale Minimum. The SCAMIN tool references the Compilation Scale of data (also called COMP SCALE) attribute value to automatically populate the SCAMIN attribute field on the applicable feature records.

What is meant by ship safety contour?

Safety Contour: A specific depth contour set by ECDIS. It demarks the boundary between “safe-water” and shallow water with an extra wide isoline and is used to give an alarm if the ship, within a time specified by the mariner, is going to cross the safety contour.

Where do you set the deep contour?

Deep Water Contour Setting:
This is normally set to twice the ship's draft. However navigating officers can use deep water contour value the way they want.

What is the purpose of Catzoc?

Category Zone of Confidence (CATZOC) are the values that used to highlight the accuracy of data presented on charts. Before the ECDIS era, mariners used to assess paper chart accuracy via Source Diagram. They also usually respond that accuracy of data depends on the number of the stars.

What is LDL Ecdis?

Safety planning
It would have been possible to draw a Limiting Danger Line (LDL) in ECDIS at that depth, which would have given the most accurate electronic picture of the safe water available.

How do you calculate your squat?

You might asked then, if there's a formula for squat on open waters, what will be the formula for squat on enclosed water? To get the value of squat on enclosed water is to multiply block coefficient by the square of speed, and then times 2, then divide the product by 100.

What is scale minimum in Ecdis?

The SCAMIN value of an object determines the display scale below which the object is no longer visible on an Electronic Chart Display and Information System (ECDIS). The purpose of SCAMIN is to reduce the amount of clutter displayed to the ECDIS user.

What is XTD in Ecdis?

The ECDIS offers already XTD (cross track distance). The ECDIS will display all the time any deviation to port or starboard from the route in meters. It will even trigger an XTE (cross track error) alarm when the ship is crossing the line.

Why is Ecdis anti grounding tool?

Anti-grounding function
The final layer of safety is the anti- grounding function. This tool allows the ECDIS to scan ahead of the ship to a distance set by the user. It acts as a final layer of safety should a navigational danger be missed by the visual check or route scan.

What are the three possible types of messages seen when there is an Ecdis alert?

Alerts are divided in three priorities: alarms, warnings and cautions.

How do you find under keel clearance?

The Gross Under Keel Clearance is found by subtracting the vessel draft from the amount of water available (depth + tide).

What is meant by safety contour in Ecdis?

Safety Contour: A specific depth contour set by ECDIS. It demarks the boundary between “safe-water” and shallow water with an extra wide isoline and is used to give an alarm if the ship, within a time specified by the mariner, is going to cross the safety contour.

What is radar overlay?

Radar overlay (a raw radar image overlaid on an electronic chart) is the best means of verifying cartographic data and the output of navigation sensors. The radar overlay feature of an ECDIS not only duplicates the radar itself, as some navigators know, but can also be used to verify the entire navigational system.