The model 1603A and 1603A-01 power measurement system is identical to the model 1602A system except for the elimination of the cover over the shaft sensor unit which enables installation in tight spaces such as under existing covers or deck plates. The system fits shaft sizes from 63,5 mm to 391 mm [2.5 in to 15.4 in] in diameter. The system has an electronics readout assembly in a water tight enclosure. These units together provide means for measuring shaft torque and RPM. Digital readouts are available to display torque, RPM and computed horsepower. Built-in calibration check circuitry can be activated at any time to verify that all local displays and outputs are functional. Enhanced stability and reduced maintenance are the payback for selecting this system. The model 1603A and 1603A-01 systems can be used in a variety of potential applications including fuel conservation programs, hull and propeller fouling, power plant monitors and sea trial torsion meters.