Ohio-class submarines are currently the only type of strategic missile carrier in the US Navy. The Ohio-class nuclear-powered ballistic missile submarines (SSBNs) were commissioned from 1981 to 1997. A total of 18 submarines were built. According to the project, each of these boats carries on board 24 intercontinental three-stage solid-propellant ballistic missiles "Trident", equipped with MIRVs with individual guidance.
On April 10, 1976, at the Electric Boat shipyard, construction began on a new strategic nuclear submarine for the American fleet - SSBN 726 OHIO, which became the lead in a large series of similar SSBNs, which were developed in accordance with the Trident program. Development and research work on the project of a new strategic missile carrier was carried out in America since October 26, 1972, and the order for the construction of the lead boat of the series was issued on July 25, 1974. Currently, all 18 boats built according to this project remain in the US Navy. 17 boats were named after US states, and one boat, SSBN-730 Henry M. Jackson, was named after Senator Henry Jackson.
The modernization of two bases was carried out especially for the basing of new submarines in the United States. One on the Pacific coast - Bangor, today it is the Kitsap naval base (formed in 2004 by the merger of the Bangor submarine base and the Bremerton naval base) in Washington state, the second on the Atlantic coast is the Kings Bay naval base in Georgia. Each of these two bases is designed to service 10 SSBNs. At the bases, the necessary equipment was installed for receiving and unloading ammunition from boats, routine repairs and maintenance of submarines. All conditions have been created to ensure the rest of the personnel. Training centers were built at each base to train personnel. They could train up to 25 thousand people every year. The special simulators installed in the centers made it possible to practice the control processes of the submarine in a variety of conditions, including torpedo and rocket firing.
Nuclear submarines of the Ohio class belong to the third generation submarines. As part of the work on the creation of third-generation submarines in the United States, they were able to achieve maximum unification of their submarine forces, reducing the number of submarine classes to two: strategic nuclear submarines and multipurpose nuclear submarines (one submarine project in each class). The Ohio-class strategic missile carriers had a single-hull design, traditional for American nuclear submarines, differing from multipurpose boats in a rather highly developed superstructure. When creating boats of this generation, close attention was paid to reducing the noise level of submarines and improving their electronic, especially hydroacoustic weapons. A feature of the third generation nuclear submarine reactors is that their resource has been increased by 2 times compared to the reactors of the previous generation boats. The reactors installed on new boats could operate continuously at full power for 9-11 years (for strategists) or 13 years (for multipurpose nuclear submarines). Previous reactors could not operate for more than 6-7 years. And taking into account the real operating modes, which were much more gentle, third-generation nuclear submarines could serve without recharging the reactor core for up to 30 years, and in the case of one recharge - 42-44 years.
To estimate the size of the Ohio-class strategic missile carriers, it is enough to say that the length of their hull is 170 meters, which is practically 1.5 football fields. Moreover, these boats are considered one of the quietest in the world. However, it was not their size and noiselessness that made them unique, but the composition of the nuclear weapons placed on board - 24 ballistic missiles. Until now, no submarine in the world can boast of having such an impressive arsenal (Russian Project 955 Borey nuclear submarines carry 16 R-30 Bulava ballistic missile launchers on board).
The first 8 Ohio-class nuclear submarines were armed with Trident I C4 ballistic missiles, subsequent submarines received Trident II D5 missiles. Later, during the scheduled overhaul of submarines, 4 boats of the first series were re-equipped with Trident II D5 ICBMs, and 4 more boats were converted into carriers of Tomahawk cruise missiles.
The SSBN data power plant was built on the basis of the eighth generation S8G reactor. In normal operation, two turbines with a capacity of 30,000 liters. with. a shaft with a propeller was rotated through the gearbox, providing the submarine with an underwater speed of 20-25 knots. However, the highlight of this type of boats was the low-noise operating mode, when the circulation pumps of the reactor's primary circuit were stopped and it switched to natural circulation. The turbines and gearbox are stopped and disconnected from the shaft using a special coupling. After that, only two turbine generators with a capacity of 4000 kW each remained in operation, the electricity they generated, passing through a rectifier converter, was supplied to a propeller motor that rotated the shaft. In this mode, the boat developed a speed sufficient for silent patrolling. The same scheme for building a power plant is used on the fourth generation nuclear submarine.
Description of the construction of boats of the "Ohio" type
Boats of the "Ohio" type have a hull of a mixed design: the strong hull of the submarine has a cylindrical shape with ends in the form of a truncated cone, it is complemented by streamlined ends, in which a spherical GAK antenna, ballast tanks and a propeller shaft were located. The upper part of the boat's sturdy hull was covered with a light, permeable streamlined superstructure that covers the missile silos, as well as various auxiliary equipment at the stern and a flexible towed GAS antenna located at the stern end. Due to the relatively small area of the light hull, the submarine is considered a single-hull. According to American experts, such a design of SSBNs creates less hydrodynamic noise and allows you to achieve the highest possible low-noise speed in comparison with double-hull submarines. The hull of the boat is divided into compartments by flat bulkheads, each of the compartments is divided into several decks. In the bow, missile and aft compartments, loading hatches were provided. The deckhouse of the boat is shifted to the bow, horizontal wing-shaped rudders are installed on it, the plumage of the boat is cruciform in the aft part, vertical faceplates are mounted on the horizontal rudders.
The strong hull of the submarine was welded from sections (shells) of conical, cylindrical and elliptical shapes with a thickness of 75 mm. The material used was high-strength steel grade HY-80/100, which has a yield strength of 56-84 kgf / mm. To increase the strength of the hull, the boat was provided with the installation of annular frames, which are spaced along the entire length of the hull. Also, the boat's hull received a special anti-corrosion coating.
The basis of the power plant of the boat is a nuclear reactor - a double-circuit pressurized water-cooled reactor (PWR) type S8G, which was designed by engineers at General Electric. It consists of a standard set of parts for reactors of this type: reactor vessel, core, neutron reflector, control and protection rods. The steam turbine power plant includes two turbines with a capacity of 30,000 hp each. each, reducer, condenser, circulation pump and steam lines. Both steam turbine units operate on one shaft, while the high speed of rotation of the turbines is reduced to 100 rpm with the help of a gearbox, after which it is transferred to the propeller shaft by means of a clutch, which drives a seven-blade propeller with a diameter of 8 meters. The propeller has beveled crescent-shaped blades with reduced rotational speed to reduce noise at patrol speed. Also on board there are two low-speed multi-pole turbine generators, each with a power of 4 mW, they generate electricity with a voltage of 450V and a frequency of 60 Hz, which, using an AC-to-DC converter, supplies power to the propeller motor (in this operating mode, the steam turbine units do not rotate the propeller).
The main armament of the Ohio-class SSBNs are ICBMs, housed in 24 vertical silos, which are located in two longitudinal rows immediately behind the retractable fencing. The ICBM shaft is a steel cylinder that is rigidly attached to the submarine's hull. In order to be able to install Trident II missiles on board, the missile silo was initially increased compared to the boats of the previous project; its length is 14.8 meters, and its diameter is 2.4 meters. The shaft is closed from above by a hydraulically operated lid that seals the shaft and is designed for the same pressure level as the submarine's rugged hull. On the cover there are 4 inspection and adjustment hatches, which are designed for routine inspections. A special locking mechanism is designed to provide protection against unauthorized access, and controls the opening of technological hatches and the cover itself.
The Trident ICBM can be launched with a 15-20 second interval from a diving depth of up to 30 meters, at a boat speed of about 5 knots and sea agitation up to 6 points. All 24 missiles can be fired in one salvo, while test launches of the entire submarine's ammunition in one salvo have never been carried out in the United States. In the water, the rocket moves uncontrollably; after it reaches the surface, according to the data of the acceleration sensor, the first stage engine is activated. In the normal mode, the engine is turned on at a height of about 10-30 meters above the sea surface.
Trident II D-5 rocket launch
Trident II D-5 missiles can be equipped with two types of warheads - W88 with a capacity of 475 kt each and W76 with a capacity of 100 kt each. At maximum load, one missile can carry 8 W88 warheads or 14 W76 warheads, providing a maximum flight range of 7360 km. The use of special astrocorrection equipment on missiles, together with an increase in the efficiency of the navigation system, made it possible to achieve a circular probable deviation for blocks W88 - 90-120 meters. When the enemy missile silos are hit, the so-called "2 by 1" method can be used, when two warheads are simultaneously aimed at one ICBM silo from different missiles. At the same time, when using W88 blocks with a capacity of 475 kt, the probability of hitting a target is 0.95. When using W76 blocks, the probability of hitting a target with the same "2 by 1" method is already 0.84. In order to achieve the maximum flight range of ballistic missiles on board usually installed 8 warheads W76 or 6 warheads W88.
For self-defense, each boat was equipped with 4 torpedo tubes of 533 mm caliber. These torpedo tubes are located in the bow of the submarine slightly at an angle to the center plane. The boat's ammunition load includes 10 Mk-48 torpedoes, which can be used against surface ships and against submarines of a potential enemy.
As part of the modernization of submarines under the A-RCI (Acoustic Rapid COTS Insertion) program, all SACs of Ohio-class boats were upgraded to the AN / BQQ-10 variant. Instead of 4 GASs, a general station of the COTS type (commercial-off-the-shelf) with an open architecture was used. This solution allows in the future to facilitate the process of upgrading the entire system. The first modernization was the boat "Alaska" in the fall of 2000. The new system, among other things, received the ability to conduct "hydroacoustic mapping" (PUMA - Precision Underwater Mapping and Navigation). This allows SSBNs to create a high resolution hydrographic map and share it with other vessels. The resolution of the equipment installed on board makes it possible to distinguish even small objects such as mines.
A special station AN / WLR-10 is used to alert the crew about acoustic exposure. Together with it, at the moment when the boat is on the surface, the AN / WLR-8 (V) 5 radar warning station operating in the range of 0.5-18 GHz is used. Also, the submarine received 8 Mk2 launchers, designed for acoustic jamming and an AN / WLY-1 hydroacoustic countermeasure station. The main purpose of this station is automatic detection, classification and subsequent tracking of attacking torpedoes and signaling for the use of hydroacoustic countermeasures.
During 2002-2008, the first 4 Ohio-class boats (SSGN 726 Ohio, SSGN 727 Michigan, SSGN 728 Florida, SSGN 729 Georgia), which were armed with Trident I ICBMs, were converted into SSGNs. As a result of the modernization carried out, each of the boats can carry up to 154 Tomahawk cruise missiles on board. At the same time, 22 of the 24 existing silos were modernized for vertical launch of cruise missiles. Each such mine can accommodate 7 Tomahawk missile launchers. At the same time, the two shafts closest to the wheelhouse were equipped with airlock chambers. These cameras can be docked with ASDS mini-submarines or DDS modules designed for combat swimmers to exit at the moment when the nuclear submarine is underwater. These funds can be installed on the boat both together and separately, with a total of no more than two. At the same time, due to their installation, the silos with cruise missiles are partially blocked. For example, each ASDS blocks three mines at once, and the shorter DDS module blocks two. As part of a special operations unit (navy seals or marines), the boat can additionally transport up to 66 people, and in the case of a short-term operation, the number of paratroopers on board the boat can be increased to 102 people.
At present, the Ohio-class SSBNs continue to hold the lead in terms of the number of missile silos located on board - 24 and are still considered one of the most advanced in their class. According to experts, among the built strategic missile carriers in terms of noise level only French boats of the "Triumfan" class can compete with these boats. The high accuracy of the Trident II ICBM allows hitting not only land ICBMs, but also the entire range of high-strength targets such as in-depth command posts and silo launchers. ocean in the zone of domination of their own naval forces, which provides the boats with a sufficiently high combat stability. The combination of low maintenance costs and high efficiency of these submarines, armed with ICBM "Trident II", has led to the fact that the naval strategic forces currently occupy a leading position in the US nuclear triad. Decommissioning of the last Ohio-class boat is scheduled for 2040.
The performance characteristics of the Ohio-class SSBN:
Overall dimensions: length - 170.7 m, width - 12.8 m, draft - 11.1 m.
Displacement - 16,746 tons (underwater), 18,750 tons (surface).
Submerged speed - 25 knots.
Surface speed - 17 knots.
Immersion depth - 365 m (working), 550 m (maximum).
Power plant: nuclear, pressurized water reactor of the GE PWR S8G type, two turbines of 30,000 hp each, two turbine generators of 4 MW each, a diesel generator with a capacity of 1.4 MW.
Missile armament: 24 ICBM Trident II D-5.
Torpedo armament: 4 torpedo tubes of 533 mm caliber, 10 Mk-48 torpedoes.
Crew - 155 people (140 sailors and 15 officers).
Base "Kings Bay" for servicing SSBNs of the "Ohio" range, assigned to the Atlantic Fleet of the US Navy
