Manoeuvring information can not be obtained from（）.

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

The helm command PORT TWENTY means（）.

The ISM code is part of（）.

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

ECDIS must be able to perform all of the following EXCEPT（）.

The company should establish and maintain procedures to control all documents and date which are relevant to（）.

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

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（）.