Every vessel shall at all times maintain a proper look - out by sight and hearing as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and of the risk of collision 每一船舶应常用视觉、听觉以及适合当时环境和情况下一切有效的手段保持正规的了望，以便对局面和碰撞危险做出充分的估计。
