A connector for a wave attenuation system formed by connecting a plurality of panels in a structure positioned in a body of water; the system causes the dissipation of wave energy. Different configurations of panel, having different flow characteristics, used in the structure, and different types of connector used to connect panels, create different patterns of water flow within the structure, and contribute to wave energy dissipation. Units deployed in harbors, rivers, marinas and the like, help to prevent beach erosion and can facilitate beach nourishment. Embodiments can be utilized as a security barrier, preventing intrusion by trespassers, divers or various sized boats. A variety of sensors can be mounted to the structures, enabling detection of movement, chemical and biological agents, explosives or radiation. A submersible gate, comprising panels and a buoyancy control mechanism, allows for passage of boats and can be controlled remotely.