Which statement best describes horizontal shadowing on the radar?

• A. As the vessel transits the coastline the RADAR picture changes with the shape of the closest land/shore.
• B. It causes the radar to be free of land clutter.
• C. It only occurs during night time.
• D. It improves radar resolution near mountains.

Answer: (A)

Horizontal shadowing happens when a landmass blocks part of the radar beam, creating a shadowed area behind it on the display. As your vessel moves along the coast, the coastline’s shape changes relative to your radar beam, so the shadow boundaries shift and the radar picture changes accordingly. This is why the coast appears in a way that tracks the shoreline geometry—the radar returns behind the land are suppressed, and new areas of possible returns can disappear or appear as you pass features like headlands, bays, or inlets.

So the statement that best describes this is the one that says the radar picture changes with the shape of the closest land or shore as you transit the coastline. It isn’t about removing land clutter, it isn’t limited to night, and it doesn’t improve resolution near mountains—the effect is the blockage and resulting shadowing caused by terrain altering what the radar can see.