Long development times and high costs limit the practical use of robots for many important field missions. Here the underlying hypotheses of a modular design approach to producing rapidly deployable, low cost field robotic systems are presented and their validity explored. An inventory of physical modules and software modules are assembled into a field robotic system for a specified task. The proposed design method uses a hierarchical selection process combined with a genetic algorithm to select a robot configuration and action plan for a given task. The method is applied to an inspection task required for the preservation of an historic ship.