This technology overcomes several serious difficulties related to aligning and attaching transducers on opposite sides of a barrier like a submarine hull or the like, when the vessel is in a body of water, or other barriers where one or both sides of the barrier may be in a hostile environment, such as under high pressure, high temperature or nuclear conditions, or a liquid environment. This technology utilizes mounting members with threaded bolt holes at their periphery. The mounting rings are rotationally aligned on opposite sides of a hull using a temporary, removable plate having multiple temporary transducers. Peaking methods are used to locate the plurality of transducers with respect to the opposite side of a wall, such as a ships hull. The mounting rings can be aligned across the wall using the known relative locations of the plurality of transducers.