Notes on Radar Navigation Lecture

Learning Objectives

• Safe and efficient use of radar for navigation.
• Making landfall and positioning the ship using radar.
• Identifying raycons and using parallel index lines.

Understanding Radar Picture

• Radar presents a plain picture of surroundings as seen from the scanner.
• Important to remember:
  • Radar cannot see what is not visible from the antenna.
  • Radar horizon is 8-10% beyond the optical horizon.
  • Effective in darkness and fog.

Categories of Radar Navigation

1. Making Landfall
2. Postal Navigation
3. Pilotage

• Particularly useful in bad visibility.
• Initial fixes at long ranges may not be reliable.
  • Land appearance may change at different ranges.

Radar Accuracy and Position Fixes

• Range accuracy is generally higher than bearing accuracy.
• Accurate position fixes typically require three radar ranges.
• Use isolated targets for better identification:
  • Reduce gain for fine echo and reduced distortion.

Navigating Narrow Waters

• Radar is beneficial during reduced visibility.
• Typically, the ship's position is not plotted on the chart.
• Use short range radar with occasional long-range overview.
• Be aware of radar shadows and differentiate between echoes of buoys and ships.
• Local knowledge can aid in identifying targets.

Enhancing Radar Detection

• Use radar reflectors for poor radar echo objects.
• Raycon: Emits a characteristic signal when triggered by ship radar.
  • Provides bearing and range information.
  • Works with X-band radars only.

Parallel Index Lines

• Useful for planning passage at a safe distance from landmarks.
• Set the cursor's bearing line to the desired course.
• Maneuver the ship to keep the echo along the parallel index line.
• Take into account current direction for adjustments.

Radar Motion Components

• Three important motion components to remember:
  1. Target's Relative Course and Speed: Movement in relation to own ship.
  2. Target's True Course and Speed: Actual motion observed.
  3. Own Ship's Course and Speed: True motion of the ship.

Collision Regulations (COLREGs)

• Follow COLREGs without exception, even when using radar.
• Use radar for early warning and planning maneuvers.
• Simulator training is required for obtaining radar observer certificate.

Key COLREG Rules Relevant to Radar Traffic Surveillance

• Rule 2: Responsibility of the owner, master, and crew.
• Rule 4: Steering and sailing rules for all visibility conditions.
• Rule 5: Maintain proper lookout by all available means.
• Rule 6: Concept of safe speed at all times.
• Rule 7: Use all means to assess risk of collision.
• Rule 8: Actions to avoid collision must be timely and positive.
• Rule 10: Traffic separation schemes.
• Rule 35: Sound signals in bad visibility.

Conclusion

• Emphasized importance of adhering to COLREGs and intelligent radar usage.
• Questions to be asked post-lecture.