High Quality Content by WIKIPEDIA articles! HMS Thetis was a 36-gun fifth-rate frigate of the Royal Navy. After nearly a decade of service with the British, she was one of two frigates transferred to Prussia in exchange for two gunboats. She served with the Prussian Navy, the Norddeutsche Bundesmarine and the Kaiserliche Marine as the SMS Thetis until being decommissioned in 1874 and broken up in 1894.