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

The loading of the ship must be done in accordance with（）.

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

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

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

A tide is called diurnal when（）.

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

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（）.

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

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