Nautical apparatus, namely, three-dimensional sonar equipment and parts thereof; scientific, nautical, surveying apparatus and instruments, namely, electronic navigational and positioning apparatus and instruments for marine and submarine applications, [ inertial navigation equipment and parts thereof in the nature of on-board computers, gyroscopes, cameras, ] acoustic equipment and parts thereof for analysis of the undersea environment, namely, [ radars, ] sonar and sounders; hydrometers; wa...