Experimental investigation on seakeeping performance of variable-structure SWATH in heading regular waves

Abstract

The variable-structure unmanned surface vehicle (VS-USV) have high maneuverability, strong survival, and multitasking characteristics in complex sea environment. In this study, a variable-structure small waterplane area twin hull (VS-SWATH) is proposed, which combines the advantages of straight strut SWATH and inclined strut SWATH. In order to study the seakeeping performance of the VS-SWATH with rotatable strut and hydrofoils at medium to low speeds, a series of seakeeping towing model tests was conducted. A variable-structure device was installed on the test model to change the strut rotation angle, and a detachable hydrofoil adjustment device was designed for the test model enabling the exchange of wingless and winged models. The test equipment includes a seaworthiness instrument system and a data acquisition system to measure values such as pitch, heave, vertical acceleration, and monitor the fluid around the ship. The test results show that the VS-SWATH can avoid resonance by changing the strut rotation angle. Hydrofoils mainly reduce heave and pitch at longer wavelengths, but their improvement in seakeeping performance is relatively limited in short waves.