Digital Rules

Printable Rules


Illustrative Questions



Radar Rules

Vessel Lights

Radar Rules

When navigating in the fog, the Navigation Rules that pertain to radar usage become paramount. Nav Rules Plus! includes a Tutorial module called "Starpath Radar Rules" which explains in detail all references to radar in the Navigation Rules six rules refer directly or indirectly to radar including an in-depth, animated explanation of the often misunderstood Rule 19d. The Tutorial demonstrates numerous scenarios in which Rule 19d comes into play, and shows what happens when only vessel A or B maneuver correctly as well as both vessels maneuvering correctly, from the point of view of each vessel's radar screen. It also includes the true motion seen from above for each scenario.

The following example show vessel B approaching from 000 degrees relative, and only vessel A is maneuvering properly. In this section there is also a very useful Maneuvering Diagram (developed by Cockcroft and Lameijer) that provides guidelines to specific maneuvers for vessels approaching from specific directions.

Show maneuvering diagram
Repeat Animation
Return to main page
Other views:
Only A maneuvers
Only B maneuvers
Both A and B maneuver
True View from overhead

A's radar, watching B
as only A maneuvers.

B's radar, watching A
as only A maneuvers.

Note that these animations were made by simply capturing the screens from Starpath Radar Trainer software. You can create similar demonstrations yourself for any traffic situation using that program. Except for "repeat animation" all links are disabled in this demo.