Columbia-Class: The Most 'Stealth' U.S. Navy Submarine Ever?

Columbia-Class: The Most 'Stealth' U.S. Navy Submarine Ever?

The Columbia-class is a real step foward.

The very first nuclear-armed Columbia-class ballistic missile submarine will hit the wide ocean in 2031, marking an enterprising beginning to a new era of undersea strategic deterrence. 

The move will bring new levels of navigational, command and control, weapons and quieting technologies to undersea warfare, as the Columbia-class will possibly be the stealthiest submarine ever to exist. The concept is both clear and well known: patrol the vast ocean in striking positions with submarine-launched Trident II D5 nuclear-armed missiles to ensure a catastrophic second strike in the event the U.S. mainland is subject to nuclear attack. 

Early construction, science and technology efforts, prototyping and advanced electronics for the submarines have been underway for several years, and now the Navy is taking a new, vigorous step to expedite the arrival of the new platforms. The Navy has awarded a Columbia-class submarine construction deal to General Dynamics Electric Boat for an amount possibly up to $10 billion to build the first two of twelve planned boats. 

Immediate work, as stated in DoD’s announcement, will include work on the U.K. Strategic Weapon Support System Kit as well as “continued design completion, engineering work and design support efforts.” The deal is also intended to help fortify the industrial base, the contract announcement states. 

The contract will support ongoing “tube and hull forging” to prepare the submarine’s missile tubes for integration into the boat, and also greatly accelerate current work on Columbia’s state-of-the-art, cutting edge electric drive propulsion system. 

In today’s Ohio-class submarines, a reactor plant generates heat which creates steam, Navy officials explained. The steam then turns turbines which produce electricity and also propel the ship forward through “reduction gears” which are able to translate the high-speed energy from a turbine into the shaft RPMs needed to move a boat propeller.

“The electric-drive system is expected to be quieter (i.e., stealthier) than a mechanical-drive system,” a Congressional Research Service report on Columbia-Class submarines from earlier this year states.

Designed to be 560-feet long and house sixteen Trident II D5 missiles fired from forty-four-foot-long missile tubes, Columbia-Class submarines will use a quieting X-shaped stern configuration. The “X”-shaped stern will restore maneuverability to submarines; as submarine designs progressed from using a propeller to using a propulsor to improve quieting, submarines lost some surface maneuverability, Navy officials explained.

Navy developers explain that electric-drive propulsion technology still relies on a nuclear reactor to generate heat and create steam to power turbines. However, the electricity produced is transferred to an electric motor rather than so-called reduction gears to spin the boat’s propellers.

The use of an electric motor brings other advantages as well, according to an MIT essay written years ago when electric drive was being evaluated for submarine propulsion.

Using an electric motor optimizes use of installed reactor power in a more efficient way compared with mechanical drive submarines, making more on-board power available for other uses, according to an essay called “Evaluation and Comparison of Electric Propulsion Motors for Submarines.” Author Joel Harbour says that on mechanical drive submarines, 80-percent of the total reactor power is used exclusively for propulsion.

“With an electric drive submarine, the installed reactor power of the submarine is first converted into electrical power and then delivered to an electric propulsion motor. The now available electrical potential not being used for propulsion could easily be tapped into for other uses,” he writes.

The Navy plans to ultimately build twelve Columbia-class submarines. 

Kris Osborn is the defense editor for the National Interest. Osborn previously served at the Pentagon as a Highly Qualified Expert with the Office of the Assistant Secretary of the Army—Acquisition, Logistics & Technology. Osborn has also worked as an anchor and on-air military specialist at national TV networks. He has appeared as a guest military expert on Fox News, MSNBC, The Military Channel, and The History Channel. He also has a Masters Degree in Comparative Literature from Columbia University.

Image: Reuters