High-tonnage hydraulic grabbing and rescue mechanism for underwater operations

This paper presents the design, analysis, and performance evaluation of a high-tonnage hydraulic grabbing and rescue mechanism for underwater operations. The proposed system integrates a robust mechanical claw structure with high-capacity hydraulic actuation, enabling optimal clamping force while maintaining operational precision. The grabbing mechanism features a multi-jointed arm system constructed from Strenx 700, Hardox 500, and S355 materials for extreme underwater conditions and repetitive loading. A regenerative hydraulic circuit enhances response speed and energy efficiency during rapid deployment and gripping actions. Through theoretical modeling, finite element and kinematic simulations, three kinematic configurations (V1, V2, V3) were evaluated for stroke efficiency, force transmission, and structural safety. The final configuration, V3, provided optimum gripping coverage, load distribution, and kinematic reach for irregularly shaped targets, including submarines, transport vehicles, and ship hulls. The proposed system offers a scalable and reliable solution for marine intervention scenarios, including rescue, wreckage retrieval, and subsea infrastructure handling.