Abstract

Ship draft measurement is of great significance for ensuring navigation safety and facilitating ship control. In this work, a self-powered water level sensor based on a liquid–solid tubular triboelectric nanogenerator (LST-TENG) is proposed and analyzed. The LST-TENG is made of multiple copper electrodes uniformly distributed along a polytetrafluoroethylene (PTFE) tube. When water flows into the PTFE tube, it induces alternating flows of electrons between the main electrode and the distributed bottom electrodes. The obvious peaks in the derivative of open-circuit voltage with respect to time are found to correspond with the electrode distribution. Then it can be utilized as a robust and sensitive indicator for detecting the water level as the number of obvious peaks in the derivative of open-circuit voltage is directly related to the water level height. The ship draft is successfully detected using the LST-TENG with an accuracy of 10 mm. It shows that the water level sensor has stable performance for liquid–solid interface monitoring. Therefore, this LST-TENG is self-powered, robust, and accurate for extensive applications in marine industry.