Sailing Glossary - Term Still well (or stilling well)

A cylinder installed in a body of water or an evaporation pan to hold a sensor, such as a float to measure water level or a hook gage. The stillwell is constructed so that there is free movement of water in and out of it, and it therefore provides a representative sample of the water body. It functions to protect the sensor in some cases and to provide an undisturbed water surface in other cases.