Is this a （）(淡水) tank?A、bilge waterB、ballast waterC、fresh waterD、sea water

When measuring the oxygen content of the cargo tanks prior to loading cargoes requiring vapor recovery，check it ______.

A.one meter from the tank bottom and one meter below the tank top

B.one half the ullage of the tank and one meter below the tank top

C.one half the ullage of the tank and one meter above the tank bottom

D.at three meter intervals from the tank top to the bottom

The free surface effects of a partially full liquid tank decrease with increased ______．

A.Density of the liquid

B.Placement of the tank above the keel

C.Displacement volume of the ship

D.Size of the surface area in the tank

An alarm device inserted between the deaerating tank and the expansion tank can notify the on-watching crew that .

A.the expansion tank is lack of water

B.the expansion tank is over flowing

C.there is something wrong with the cooling system

D.there is something wrong with the engine

Frames to which the tank top and bottom shell are fastened are called ______.

A.intercostals

B.stringers

C.tank top supports

D.floors

You are planning to use a crude oil washing system．What precaution must be taken with the tank as the source for the washing machines ________．

A.It must be debottomed and the level lowered by at least one meter

B.The oil in the source tank must be sampled for compatibility

C.The source tank must have been crude oil washed at least once in the past 150 days

D.The inert gas system must lower the oxygen content to a maximum of 12% oxygen in the tank

While testing a cargo tank，your oxygen indicator reads 25% oxygen in the tank. You would then ______.

A.enter the tank safely

B.suspect the accuracy of the reading

C.ventilate the tank

D.test for nitrogen

When referring to quantity of barite in a P-tank，ullage is the ______．

A.Distance of the barite surface above the tank bottom

B.Percentage of barite in the tank

C.Distance of the barite surface below the tank cover

D.Total weight of barite in UPC（ullages per centimeter）

A tank has been sealed and unventilated(不通风的) for a long period of time. Which of the following conditions does this indicate?

A.The tank is safe to enter

B.The tank is especially dangerous to enter

C.Carbon monoxide(一氧化物) is present

D.Water vapor present when the tank was sealed has oxidized(使氧化)

Frames to which the tank top and bottom shell are fastened are called ______．

A.floors

B.intercostals

C.stringers

D.tank top supports