Akula-Class Submarine

The Akula incorporates a double hull system composed of an inner pressure hull and an outer "light" hull. This allows more freedom in the design of the exterior hull shape, resulting in a submarine with more reserve buoyancy than its western analogs. This design requires more power than single-hull submarines because of the greater wetted surface area, which increases drag.

The distinctive "bulb" or "can" seen on top of the Akula's rudder houses its towed sonar array, when retracted. Most Akulas have the SOCKS hydrodynamic sensors, which detect changes in temperature and salinity. They are located on the leading edge of the sail, on the outer hull casing in front of the sail and on the bottom of the hull forward of the sail. All Akulas have two T-shaped doors on the aft bottom of the hull, on either side. These are where the OK-300 auxiliary propulsion devices are located, which can propel the submarine at up to 5 knots (9.3 km/h).