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

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

（）is where the crew eat their meals.

When steering by autopilot,how often should the steering be checked?（）

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

Full details of all lights and fog signals are shown on（）.

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

The ISM code is part of（）.

How long are you prohibited to consume alcohol prior to serving as a member of a watch?（）

Where would you find information about the time of high tide at a specific location on a particular day of the year?（）