Various applications in the past have led to the development of several optical alignment systems. More recently an electrooptic alignment system which is insensitive to angular displacements has been built. It consists of an intensity-modulated laser, a lens and a Schottky barrier position-sensing photodiode. Another afocal lens system with unit magnification has been developed to monitor displacement and tilt of an object moving in a straight line however, it either measures displacement and is unaffected by tilt or measures tilt and is unaffected by displacement. Therefore, two assemblies need to be mounted side by side in a common block to measure tilt and displacement simultaneously. This report describes a ship flexure monitoring system which has been developed to measure four degrees of freedom simultaneously. This system does not measure roll, the fifth degree of freedom however, by using a polarizer or half-wave plate and detecting polarization changes, roll measurements can be incorporated.