New Delhi, Feb. 2 -- In 1992, Naval Headquarters (NHQ) formulated a new staff requirement under 'Project 75' (P-75). An improved technology over the existing in-service was sought. Along with a lesser acoustic signature, TLM for an improved anti-ship capability was sought. At that point, MDL had established manufacturing facilities specifically for the Type 1500 class. Besides, the Submarine Design Group (SDG) was familiar with the Type 1500 hull for necessary improvements. So in 1997, once again a decision was taken to resume the construction of the two Type 1500s at MDL but with the collaboration of a non-German foreign agency to validate the design to be developed by SDG of the Indian Navy. The Letter of Intent (LoI) was sent to four fir...