Design of an Unconventional ASV for Underwater Vehicles Recovery: Simulation of the motions for operations in rough seas

Paper introduces main characteristics and particulars of an innovative design for an Unmanned Surface Vehicle to autonomously launch and recover AUVs (Autonomous Underwater Vehicles) in open sea. The USV has an unconventional SWATH hull shape and in its smaller size version, it has dedicated hangar at midship that can host one medium size AUV, completely recovered onboard. The focus of this paper is concentrated on the prediction of the steady and unsteady hydrodynamic characteristics in terms of hull resistance and motion in waves. The seakeeping prediction is made by a fully viscous 3D Unsteady NavierStokes solver. The predicted pitch and heave response of the USV-SWATH in relatively high regular waves, in the nonlinear regime, are compared with those of an equivalent catamaran vessel and dramatic reduction in vertical motions and accelerations are found. On this good basis the paper concludes presenting a first hypothesis of the L&R system based on self-tensioning winches with hoists and belt assemblies.