Due to lapse of time the risk in these areas to surface navigation is now considered （）than the ordinary risks of navigation，but a very real risk still exists with regard to anchoring，fishing or any form of submarine or seabed activity.

Lateral movement of the vessel to leeward of its course defines （）.

The distance between any two meridians measured along a parallel of latitude （）.

The height of a light is measured from which reference plane?（）

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

On a voyage from Halifax,N.S.,to Dakar,West Africa,the Canary Current will （）.

Attention is called to the fact that in many cases pipelines are not （） and charted depths may be decreased by up to 2 meters．

A pilot vessel on pilotage duty at night will show sidelights and a sternlight （）.

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

The height of tide is the （）.