单选题Ullages on tankers are measured from（）.A an above-deck datum such as the top of the ullage pipeB the tank ceiling aboard transversely framed vesselsC the tank topD a thievage mark below the edge of the deck

The dangerous semicircle of a hurricane in the Northern Hemisphere is that area of the storm ______.

A.to the right of the storm's track

B.measured from true north clockwise to 180°T

C.measured from true north counterclockwise to 180°T

D.between the ship's heading and the bearing to the eye

In the case of new crude oil tankers，the additional ballast permitted shall be carried in cargo tanks only if such tanks have been ______ before departure from an oil unloading port or terminal.

A.inerted

B.crude oil washed

C.diluted

D.cleaned

The height of a light is measured from which reference plane?

A.Mean low water

B.Mean high water

C.Average water level

D.Geographical sea level

______:the vertical distance measured on the vessel’s side amidships from the load water line to the upper side of the freeboard deck or a point corresponding to it.

A.Buoyancy

B.Freeboard

C.Draft

D.Displacement

Regulations require that cargo pumps in tankers carrying grade D liquid cargo shall be isolated from sources of vapor ignition by ______．

A.Cofferdams

B.Gastight bulkheads

C.Passageways or living quarters

D.General cargo spaces

The dangerous semicircle of a typhoon in the Southern Hemisphere is that area ______.

A.measured from due south clockwise 180°

B.measured from due south counterclockwise 180°

C.to the left of the storm's track

D.ahead of the typhoon measured from the storm's track to 90°on each side

International Certificate of Fitness for the Carriage of Dangerous Chemicals in Bulk shall be carried on board by ______．

A.chemical tankers constructed on or after 1 July 1986

B.chemical tankers constructed before 1 July 1986

C.All chemical tankers

D.oil tankers of 150 gross tonnage and above

When navigating in high latitudes and using a chart based on a Lambert conformal projection，______.

A.a straight line drawn on the chart approximates a great circle

B.the chart should not be used outside of the standard parallels

C.the course angle is measured at the mid-longitude of the track line

D.distance cannot be measured directly from the chart

Which statement is TRUE concerning inert gas systems on tankers ________．

A.Flue gases from the ship's boilers are used in some systems

B.The gas is helium

C.Using the system accelerates the rusting of the tanks

D.All of the above