What is it called when it is possible to ignite the vapour above the oil?（）

It is dangerous for vessels without the operational radar（）the estuary.

The dew point temperature is（）.

（）is halfway between the forward and after perpendiculars and is reference point for vessel construction.

（）is where the crew eat their meals.

When the wave period and the apparent rolling period are the same（）.

Manoeuvring information can not be obtained from（）.

Berthing means bringing a vessel to her berth until（）.

The mean draft of a ship is the draft（）.

Which of the following is not an operation mode of AIS?（）