BALLISTIC Missile Submarines also known as SSBN (Ship, Submersible Ballistic Nuclear) or Boomers are larger compared to other types of submarines, they are capable of launching SLBMs (Submarine Launched Ballistic Missiles). They can fire the missiles while being submersed at a depth of around 50 meters. These are basically designed to provide undetectable launch platform for ICBMs; they have stealth capabilities along with the capability of precision delivery of Nuclear Warheads. The Ohio christened Class SSBNs in the US navy, which are names so because of being made in Ohio, has the capacity to carry 24 SLBMs having multiple, independently targeting warheads. SSBNs uses various noise reduction mechanism=s in order to remain undetected underwater. SSBNs with their wide range of onboard weaponry, nuclear capabilities and stealth characteristics give it a lethal first strike capability as well as the mobility of the launch platforms offers deterrence against attacks.
Presently all Ohio class submarines have their 2 forward most missile tubes converted into advanced SEAL delivery system capable lockout chambers .They also carry Trident II airborne missiles and MK118 digital torpedoes .They carry a crew of around 20 officers and 120 enlisted men. They can spend around 850 days in sea and docks for around 28 days for overhauls; it can operate for up to 12-15 years between any major overhauls. Few of the SSBNs are also fitted with tom-hawk land missile systems
The active classes of SSBMs around the world are Le Triomp-hant Class of the French navy, Van-guard class of the UK , Typhoon class , Delta II and Delta IV classes of the Russian navy and Type 092 and type 094 of the Chinese navy. Indian navy is currently testing its Arihanth Class SSBNs. These SSBNs carry a variety of sensors onboard, which include surface search, navigation and fire control radars, passive search sonar, passive towed arrays, etc.