"减摇鳍装置" can be translated into English as "fin stabilizer system" or simply "fin stabilizer" (when referring to the device itself without emphasizing the system aspect).
Fin stabilizer system emphasizes the overall setup or configuration, including the fins, control mechanisms, and associated components.
Fin stabilizer typically refers to the physical fin device that is installed on a vessel to reduce rolling motion.
Both terms are commonly used in the maritime and naval engineering fields, with the choice depending on the context and level of specificity required.