The distance between any two meridians measured along a parallel of latitude and expressed in miles is the （）.

Clearance gauges at bridges indicate （）.

The distance between the surface of the water and the tidal datum is the （）.

The distance from the still water level (corrected for tides and storm surge) to the bottom of the hull of a ship is the（）.

Attention is called to the fact that in many cases charted depths may be decreased by up to （）.

A tug is to assist in docking an oceangoing vessel on a hawser. The greatest danger to the tug is （）.

During a period of whiteout，you should expect which of the following（）.

Information on the operating times and characteristics of foreign radiobeacons can be found in which publication? （）

A vessel not to impede the passage of another vessel is not relieved （） taking collision-avoiding action.

In Admiralty Sailing Directions，bands is the word used to indicate（）marking．