First reported by the Delhi Defence Review site on July 17 2021, the SOV-400 is a new submarine design from Larsen & Toubro. As it’s name implies it is around 400 tons placing it at the larger end of the ‘midget submarine’ spectrum.
The SOV-400 appears optimized for Special Forces missions, carrying 10 SF operators. Two 4-person SDVs (Swimmer Delivery Vehicles) can be hung on the lower hull. This gives the SF combat swimmers a means to conduct longer-endurance missions. So for a cross-beach mission a 4-6 person team could be inserted by the two SDVs, with two remaining as drivers. 2 more SF personnel would remain aboard the SOV-400 to coordinate and support the mission.
For self-defense, or targets of opportunity, the SOV-400 is armed with two 533mm (21″) heavyweight torpedoes carried externally. There is a modest sonar in the bow, but logically this will primarily be for surface targets. The exact model of torpedo is unspecified and likely to be adaptable to customer needs.