Stevens Institute of Technology has been conducting development and field tests of various underwater passive acoustic systems for several years. Several such systems provided localization of boats and divers triangulation. The new version of SPADES has a tethered low-cost bottom-mounted circular 2.2-m underwater acoustic array with eight custom-built hydrophones. The cost of the array was significantly reduced by manufacturing the hydrophones in-house and utilizing a lightweight and low-cost tether. The tether can provide power and communication up to 1 km away and power to the data acquisition. The software has been developed for real-time direction-finding using Steered Power Response Phase Transform (SRP-PHAT) method, combined with region-zeroing (RZ) approach to multi-source separation and custom noise background estimation subtraction. The array was tested for seven months in the shallow and busy waters of the Hudson River tracking small boat activity. The system’s reliability and long tether make it attractive for long-term observation of underwater noise such as monitoring wind farm noise marine mammals and shipping traffic. Direction-finding can help identify noise unrelated to wind farms.