navigational hazards meaning in English

航运的危害
影响航行的险情

Large scale charts are intended to be used for entering harbors or anchorages or for passing close to navigational hazards
大比例尺海图供驶入港口，锚地或近距离通过航海危险物时使用。
With the interaction of the strong currents over the many reefs the topography is in a state of constant flux and development of new navigational hazards is swift
藉由许多暗礁上强烈涌流的交互作用地质是新的航行危险的持续不断出现情形和发展是迅速的。