Upon the enactment of the 1962 United States Tri-Service aircraft designation system, the HU2K-1 had been redesignated as the "UH-2A", while the "HU2K-1U" model was redesignated as the "UH-2B". During its service, the UH-2 Seasprite would be subject to several modifications and improvements, such as the addition of fixtures for the mounting of external stores. Beginning in 1968, the Navy's remaining UH-2s were extensively remanufactured; perhaps the most extensive alteration performance was the replacement of their original single-engine arrangement with a more powerful twin-engine configuration.