安全水域标志（safe water marks）设在航道中央或航道的中线上，标示该标志周围均为可航水域，船舶可在其任何一侧航行，该标亦可代替方位标或侧面标指示接近陆地。
双语例句
1
At least two remote water gauges should be installed in the control chamber. A clear mark should be made at the highest and lowest safewater line, which each remote water gauge runs as regulated.