Abstract: To address the shortcomings of marine linear vibration absorbers-including inadequate low-frequency vibration reduction performance, limited environmental adaptability, and narrow operating bandwidth-a connecting-rod-hinged nonlinear energy sink (NES) was designed for broadband line spectrum control in marine mechanical equipment. The design principles of the NES prototype were elaborated, its differential equation of motion derived, and the conditions for achieving essential nonlinear stiffness established. The coupled NES system was modeled, and its dynamic characteristics analyzed via the incremental harmonic balance method, with comparisons drawn to an equivalent linear vibration absorber. Asimulation test bench was constructed for experimental validation. Results demonstrate that the NES achieves vibration reduction exceeding 6 dB within the 8~22 Hz frequency band, offering a novel technical approach for marine vibration control and significantly enhancing ship acoustic stealth performance.