You are approaching a large steel-hulled vessel or dock structure at close range and notice several equally-spaced echoes appearing on the same bearing, at multiples of the true range. Your examiner asks you to explain this phenomenon.

A. Multiple echoes are caused when the transmitted pulse bounces back and forth several times BETWEEN OWN SHIP and a large, close, strongly-reflective target (such as another ship's steel hull, a large dock or jetty structure) before finally returning to the scanner. Each "bounce" adds an additional round trip to the timing, so the radar displays a series of echoes on the SAME BEARING as the real target, at RANGES that are approximately whole-number MULTIPLES of the true range (e.g. genuine target at 1nm may show additional false echoes at approximately 2nm, 3nm, etc., each progressively weaker). This is most noticeable at close range alongside large, flat, reflective structures.

B. Multiple echoes are caused by the vessel's own superstructure reflecting the beam onto a genuine target before the echo returns, producing one false echo at the correct range but a false bearing.

C. Multiple echoes occur when energy from the radar's side lobes illuminates a target, causing a ring or arc of weaker echoes to appear around the true target at the same range but different bearings.

D. Multiple echoes are simply the radar's way of displaying a large target's physical length — the additional echoes represent the true physical extent of the vessel or structure, not a false artefact.

A. Nothing — a test lift can proceed immediately after repairs

B. Testing should wait until cargo operations begin

C. The area within the grab's swing radius should be cleared of personnel before the lift

D. Only the crane operator needs to be aware the lift is happening

A. Who must remain clear of the exclusion zone while the lift takes place

B. The lunch schedule for the deck team

C. Only the weather forecast for the next watch

D. The cargo manifest for the next port