单选题A partly submerged vessel or object being towed，which is not readily noticeable，shall show （） .A yellow lights at each endB two red lights in a vertical lineC a black ballD a diamond shape

Which vessel may show three lights in a vertical line，the top and bottom being red and the middle being white?

A.A vessel engaged in diving operations

B.A pilot vessel

C.A vessel trawling

D.All of the above

A single vessel being towed alongside shall exhibit ______.

A.one all-round white light

B.sidelights and a stern light

C.only the outboard sidelight and a stern light

D.a masthead light，sidelights，and a stern light

The maximum draft to which a vessel can legally be submerged is indicated by the ______.

A.Loadline mark

B.Certificate of Inspection

C.Station Bill

D.Tonnage mark

A vessel or object being towed astern shall display a(n) ______.

A.forward masthead light

B.after masthead light

C.stern light

D.All of the above

A partly submerged vessel or object being towed，which is not readily noticeable，shall show ______.

A.yellow lights at each end

B.two red lights in a vertical line

C.a black ball

D.a diamond shape

A vessel aground would show the same dayshape as a ______.

A.vessel towing a submerged object

B.dredge underway and dredging

C.hydrographic survey vessel at anchor and surveying

D.None of the above

A pilot vessel may continue to sound an identity signal if she is ______.

A.aground

B.at anchor

C.not under command

D.being towed

If practical, when shall a manned vessel being towed sound her fog signal?______.

A.Immediately before the towing vessel sounds hers

B.Immediately after the towing vessel sounds hers.

C.As close to the mid-cycle of the towing vessel’s signals as possible

D.At any time as long as the interval is correct