The force resulting from the earth’s rotation that causes winds to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere is called（）.

The helm command PORT TWENTY means（）.

According to the relevant regulation, lifeboat should be powered by（）.

Shipboard Emergency Drills must be carried out at least（）on board cargo ship.

Despite the rising importance and great convenience of the gyrocompass,the magnetic compass still retain its importance because of its（）.

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

Which of the following shall not the officers in charge of the navigational watch do?（）

Bales close to the deckhead should be covered to prevent（）.

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

（）is on the panel of radar.