Turkey's STM Defence has started construction of a new class of indigenously-designed diesel-electric submarines.
Classified by developers as "small-sized submarines," the STM500 boats will be capable of operating in both deep-sea and shallow waters. Missions will include surveillance, reconnaissance, and support for special operations forces.
The 500-tonne, 42-metre-long submarines will each have a maximum endurance of 30 days and forward tubes that can house and launch torpedoes as well as guided missiles.
Upon completion, the first STM500 submarine will be supplied to an undisclosed customer. STM expects construction to be completed within 48 months.