针对因水电站黑起动等特殊运行工况引发的水位突变，使所在水域停泊的船舶易发生翻沉、搁浅等情况，开发并研制出了船载便携式水位突变预警仪。该预警仪以单片机为控制核心，由温度测试电路、超声波发射接收电路、数据显示电路及报警电路组成，可实时监测船舶干舷高度、横倾斜度及所在水域的水位变率。当船舶所在水域水位发生突变且船舶干舷高度、横倾斜度及水位变率中任一项或全部超过了安全限值，预警仪会自动发出警报，同时，将这3个值的变化情况及时反馈给船员，警示船员调整船舶姿态，从而能更好地保证停靠船舶在水位突变情况下的安全。相对于传统预警系统，该预警仪具有造价低、体积小、质量轻、安装简便等优点，可以广泛应用于水位突变预警及其所在水域行进或停泊船舶的安全监控。

If water level changes abruptly in specific operating conditions such as power plant's black start, ships are prone to be capsized or stranded. In light of these conditions, a portable onboard apparatus for pre-alarming the abrupt change of water level is developed. The apparatus consists of temperature testing circuit, ultrasonic transmitting and receiving circuit, data display circuit and alarming circuit, with singlechip as the control core. Using this apparatus, three values such as the freeboard height, inclination of ships, and the water level change rate in the surrounding water area can be monitored instantaneously. When water level changes abruptly and one of the three values or all values exceed safety limit, the pre-alarming apparatus will automatically alarm and feedback the variations of these values to the crew in time, and alert the crew to adjust in order to ensure the safety of docked ships. Compared with traditional early warning system, it has many advantages such as low cost, small size, light weight, and easy installation. Finally, it can be applied to pre-alarming the abrupt change and safety monitoring of docked or navigational ships in the surrounding water area.