Abstract: A portable tracking array to be used in a system for determining the track nd/or the range of a target vehicle. The array includes a fiber optic hydrophone for acquiring acoustic signals from the target vehicle. The fiber optic hydrophone is encapsulated within a plastic material such as polyurethane. The array further includes a fiber optic cable for transmitting signals to and for receiving signals from the fiber optic hydrophone, which fiber optic cable has an end encapsulated within a termination coupling, and a length of perforated material extending between the terminal coupling and the plastic material encapsulating the fiber optic hydrophone to allow water entry and to substantially eliminate air cavities which interfere with acoustic performance.