The TCM-3 is a current meter that is designed to operate off the continental shelf in water up to 4500m depth. The TCM-3 is constructed from toughened syntactic foam with a titanium pressure housing and is easily deployed by small ROVs. The relatively low cost makes it feasible to accurately measure current in many locations simultaneously.
The core of the TCM-3 is the MAT-1 Data Logger. The MAT-1 data logger was designed for NOAA and is ideally suited as the "brains" of a tilt current meter. The built-in data logger includes a USB communication interface, a microSD flash memory card, and a long-life lithium battery.
The TCM-3 Tilt Current Meter measures current using the drag-tilt principle. The logger is buoyant and is typically attached to the bottom via a short flexible tether to a small lead or concrete anchor. Moving water tilts the logger in the direction of flow. The TCM-3 contains a 3-axis accelerometer and 3-axis magnetometer for measuring tilt and bearing. The resulting orientation data is converted to current by applying calibration coefficients with the included software.