Question 894Navigation General

The correct answer is B) They always appear on a bearing of 90° from the true bearing of the contact. This is because indirect echoes, also known as "ghost" or "false" echoes, are caused by the radar beam reflecting off the observer's own vessel, not the target vessel. The bearing of the indirect echo will not be 90 degrees off the true bearing, but rather dependent on the relative position and orientation of the observer's vessel. The other answer choices are correct characteristics of indirect echoes - they tend to have a constant bearing, their movements are abnormal, and they often appear in shadow sectors where the main radar beam is obstructed. However, the bearing of the indirect echo is not fixed at 90 degrees from the true bearing.