Ohio class
.jpg) USS Maine (SSBN-741) at the surface of the water in 1999 |
|
| Overview | |
|---|---|
| Type | Missile submarine , partially converted to cruise missile platform |
| units | 18 built, 18 in service |
| Namesake | State of Ohio |
| period of service |
since 1981 |
| Technical specifications | |
| displacement |
16,764 ts surfaced, 18,750 ts submerged |
| length |
170.69 m |
| width |
12.8 m |
| Draft |
11.1 meters |
| Diving depth | 250+ meters |
| crew |
155 soldiers, 15 of them officers |
| drive |
S8G pressurized water reactor , 60,000 SHP (wave PS) |
| speed |
25 kn (46 km / h) submerged |
| Armament |
24 ICBMs or 154 cruise missiles, 4 torpedo tubes |
The Ohio-class is a United States Navy class of ships and includes the 18 largest nuclear-powered submarines in the United States . It was created during the Cold War as a carrier for ICBMs ( SLBM for Submarine Launched Ballistic Missile ); so the boats belong to the group of missile submarines . The official name of the boats in the US Navy is Ship Submersible Ballistic Nuclear , or SSBN for short . To this day, the boats remain an important part of US nuclear deterrent policy , with the Ohio class remaining the only SSBN class in the US Navy well into the 21st century. By the end of the 2020s, the submarines will have reached the end of their lifespan.
After the end of the Cold War, the need for submarines with ICBMs decreased. Since 2003, four of the boats in the class have therefore been converted to launch cruise missiles . These boats are listed as SSGN (for Ship Submersible Guided Missile Nuclear ).
history
Planning and development
The United States Navy began planning a new SSBN class in the late 1960s. At the same time, it pushed ahead with the construction of a new ICBM to be launched by submarines (' Submarine-launched ballistic missile ' , SLBM for short ), which should have considerably greater ranges than the previous models. Hence the developed Ohio class and supported by their intercontinental ballistic missile Trident . The Trident version C4 , which was first put into service, was still a temporary solution that should also be retrofitted on older boats. The further development, called Trident II or D5 for short , would only be able to be used on the Ohio . Originally the construction of ten boats of the class was planned, in the course of the global arms race - before the first delivery - the US Navy then planned up to 16 units, in 1989 even 24. In 1991, with a view to the effects of the arms limitation talks, START was made I decided to finish the class with the 18 boats that had been approved so far.
In 1974 the first boat of the class was commissioned; the executing shipyard was the Electric Boat (EB) shipyard based in Groton , Connecticut , which is part of the General Dynamics group. The delivery of the first unit was planned around 1977, in fact the commissioning of the lead ship of the class was delayed by four years and did not take place until the end of 1981. Regardless of this, all further orders also went to EB . The last unit of the class was completed there in 1997.
The boats were built in modular design. Several sections were manufactured individually and welded together in the shipyard. At this point in time, the individual sections were already partially equipped inside, so that only cables, air ducts and the like had to be laid after they were combined. This design reduced the working hours of the shipyard workers in the narrow interior of the boats as much as possible.
The cost of the first unit was estimated at $ 780 million in 1974, and the eighth unit in 1980 at $ 1.12 billion. By 1985 the cost of a boat had risen to $ 1.8 billion. The main reasons for this were the high rate of inflation as a result of the 1973 and 1980 oil crises and EB's monopoly in the construction of boats.
The naming of the boats was a novelty: For the first time, submarines were classified as important units ( capital ships ) of the US fleet. Only such units receive the names of US states in the tradition of naming the US Navy . Before the Ohio , only battleships and a few nuclear cruisers received such names. An exception is SSBN-730, which should actually be called Rhode Island , but was named in honor of the US Senator Henry M. Jackson, who died shortly before the ship was christened .
Modifications
The first eight boats of the class are intended for the launch of the Trident I C4 , the first variant of this nuclear missile. The shipyard has already equipped the last ten units for the more powerful and more precise Trident II D5 . Four of the first eight boats were modified from 1996 in order to also be able to take the newer D5 version on board, whereby the C4 was completely withdrawn from service. The conversion of the last of the four boats was completed in 2006. Since the C4 was intended as a transitional solution from the start, the first Ohios were built with enough space to be able to carry the D5 version, which has been enlarged in length and diameter after the conversion.
As early as 1994, the Nuclear Posture Review , an evaluation of the position of nuclear weapons by the United States Department of Defense , decided that 14 SSBNs would suffice for deterrence in the post-Cold War era. After the ratification of the 1993 START II disarmament treaty, the first four boats were to be decommissioned in 2002 and 2003. After the Russian Duma continued to delay ratification and since the submarines were still in good condition, a rethink began in 1999. The United States Congress approved funds to prepare a concept study to investigate whether the four boats could be made into platforms for launching cruise missiles. A year later, additional funds were approved for a design study, and in 2001 the first funds for the actual conversion of four boats.
To do this, the original Trident launch tubes were removed and launchers for seven missiles per former Trident ICBM were installed. Two of the former pipes have also been converted as entry and exit hatches for divers, so that the boats can carry out special operations. The cost of the conversion is around $ 700 million per boat. The first two boats were rebuilt in the Puget Sound Naval Shipyard , the second pair went to the Norfolk Naval Shipyard . This created the first SSGN ( Ship Submersible Guided Missile Nuclear ) of the US Navy since the USS Halibut (SSGN-587), which was commissioned in 1960 .
The Ohio was the first SSGN to join the fleet in late 2005, the Georgia the last in 2008.
Working time
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The Ohio-class boats replaced the George Washington and Ethan Allen -class boats in the early 1980s , all of which carried the first ever submarine-based ICBM, the UGM-27 Polaris . The remaining years of the Cold War, the incoming Ohio-class boats complemented the 31 Lafayette-class boats , the last of which were decommissioned in 1995.
The Ohio-class boats were originally intended to be used for 30 years, as is the standard assumption for US warships. As early as 1995, the US Navy examined the possibility of extending the service life of the boats to up to 40 years. From 1998 onwards, the Navy officially assumed that the boats could be kept in service for 42 years, divided into two 20-year deployment windows with an overhaul in between. This extension could be achieved because the boats wore out much less quickly than Jagd-U-Boats (SSN). One of the reasons for this is the much "quieter" modus operandi. The Ohio draw on their patrols their orbits at constant speed and at the same depth. At the same time, they dive less deep than SSN and are therefore exposed to less pressure. Since previous SSBNs were decommissioned due to disarmament treaties before the end of the assumed 30-year service period, the longer term was important for the Ohio for the first time.
In 2010, the US Navy began developing a successor to the Ohio class under the designation SSBN-X. This has been known as the Columbia class since 2016 and should be available from 2030.
technology
hull
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The hull of an Ohio-class boat is 170 feet long and 12.8 feet wide. As with the hunting submarines of the Los Angeles class , the pressure hull is basically cylindrical with closing caps at the ends and is supported by circular transverse ribs . In addition to the inner pressure hull, the boats also have a free-floating outer hull layer into which the main ballast tanks are incorporated. The sonar system is located between the hulls at the bow and the drive shaft at the stern, which is guided out of the pressure hull by means of a stuffing box . The pressure envelope is made of highly elastic HY-80 steel . This means that the steel has a guaranteed 'yield strength' ( yield strength ) of 80,000 psi ( pounds per square inch has). This is the limit of materials up to which no permanent deformation occurs. This corresponds to about 551.6 MPa here . Another advantage of this steel, which is mainly used for shipbuilding, is its good weldability. The entire boat is largely demagnetized in a system called Magnetic Silencing Facility in order to prevent detection by enemy magnetometers ( Magnetic Anomaly Detector , MAD).
In contrast to hunting submarines, a section is incorporated behind the tower in which the rocket shafts are housed and which can be recognized from the outside by a slight hump. When submerged, an Ohio displaces 18,750 ts, more than twice as much as its predecessor in the Lafayette class . Otherwise only the SSBN of the Typhoon class , planned and built in parallel by the Soviet Union, achieve similar dimensions , which are a few meters longer and almost twice as wide and displace over 26,000 ts.
The boats' down rudders are attached to the tower, and other steering devices are located at the stern; The down and rudder controls are installed in a control pad. The diving depth is officially stated as 800+ feet - around 250 meters - in fact the boats should be able to dive 300 meters or deeper.
In the forward compartment , which extends from the bow to behind the tower, the hull offers enough space for four decks. All command and control rooms such as the bridge , the sonar, radio and missile control rooms and the torpedo room are located there . There are also the officers 'quarters and the officers' mess as well as the dining and lounge rooms for the men and the first auxiliary engine room. Directly aft of the tower is the missile compartment . This largest department takes up around half of the ship. Because of the vertical missile shafts located there, the room is also called Sherwood Forest . In addition to the shafts, there are also quarters for the crews, storage rooms and the second auxiliary machine room. The reactor department, which is shielded from the adjoining rooms, is connected to the Sherwood Forest . Staying in these areas is also strictly regulated. Aft of this is the engine room with the non-nuclear secondary circuit and the turbines as well as the drive shaft, which emerges through the pressure hull at the very aft.
drive
The Ohio submarines are powered by two steam turbines that produce 60,000 SHP (shaft horsepower) (about 44.7 MW) and act on a shaft. The drive energy is generated by a pressurized water reactor of the type S8G . S stands for the ship type, here submarine , 8 for the reactor generation and G for the manufacturer, General Electric . According to official information, the submarines can reach speeds of 20+ knots, the actual speed is around 25 knots.
Several measures have been taken to counteract drive noises, which contribute significantly to the noise development in submarines: The propeller consists of seven long, sickle-shaped blades made of bronze , which rotate slowly even at high speeds in order to avoid cavitation . Depending on the speed, one of two different turbines is activated in order to only cause as much noise as is unavoidable in every situation. The turbines themselves and other sensitive drive parts are mounted on a "raft" that dampens vibrations before they can be transmitted into the water via the hull. At slow to medium speeds, the reactor pumps can also be switched off, since the natural convection of the cooling liquid is sufficient to transport it through the reactor. This function was first tested in the reactor on the USS Narwhal (SSN-671) and then used in series on the Ohio .
In the event of a reactor failure, there are a large number of batteries in the bottom of the boat to provide power to restart the reactor. In addition, every boat has a 325 HP auxiliary motor, produced by Magnatek , which can be used in such cases.
Armament
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The main armament of the Ohio-class boats are 24 submarine-based Trident ICBMs , which are stored in two rows of twelve vertical launch tubes . The start is possible submerged, multiple starts are also possible. However, reloading at sea is not possible; a loading crane is required for this, which lowers the missiles from the outside into the shafts. The first eight boats built were initially equipped for the Trident I C4 . This 10.2 meter long and 33 tonne rocket with a diameter of 1.8 meters has a range of 7400 kilometers and an accuracy of 380 meters. It can eight independent warheads of the type W76 up to 100 kilotons with an explosive force of TNT equivalent wear.
The four modernized early boats and any later ten boats can fire the more modern Trident II D5 . This is 13.4 meters long with a diameter of 2.1 meters and a weight of 58.5 tons. It is more precise with an accuracy of 90 meters, has a greater range of 12,000 kilometers and can also carry eight W88 warheads with an explosive force of up to 475 kilotons. The equivalent explosive power carried by every Trident submarine thus exceeds the explosive power of all conventional explosives used during World War II .
In the four boats converted to SSGN, 22 of the 24 tubes were converted in order to be able to launch UGM-109 Tomahawk cruise missiles, also submerged . Since a tomahawk is only six meters long and has a cross-section of 50 centimeters, seven missiles can be accommodated per slot, so that an Ohio can transport 154 cruise missiles. The two remaining pipes have been converted into entry and exit hatches for combat divers, making the boats suitable for special operations. For such missions, each boat can also carry two dry deck shelters outside of the pressure hull.
All boats have four torpedo tubes in common for self-defense. They are located in the bow under the tower and are angled slightly outboard. These tubes with a diameter of 533 millimeters fire the Mark 48 heavyweight torpedo for use against submarines and surface ships. There are around a dozen weapons of this type on board.
electronics
_sonar.jpg)
The main sonar system on Ohio-class boats is the BQQ-6 , which consists of a spherical sonar in the bow. This can only be used passively to search for targets; The system does not have an active mode, as used on hunting submarines. There are also sonar types BQS-13 and -15 and BQR-19 . BQR-19 is an active, short-range navigation sonar, the two BQS systems are passive for fire control for the torpedoes (-13) and active at high frequencies for use under ice and for the detection of small objects such as mines (-15) . During the patrol, a towing sonar can also be deployed, which can listen into the blind spot behind the boat and thus track down any pursuers.
Several masts can be extended from the tower. These can only be used if they can break through the water surface, for this the boat must be at periscope depth (approx. 20 meters) or higher. There are two periscopes for visual exploration of the surface , one for attack situations with a small seeker head to minimize the radar cross-section and a larger search periscope. For navigation on the surface, for example when entering a port, there is also a radar system that transmits on the I-band . In contrast, a radar warning system on a mast can be extended in order to search for active radar sources such as enemy warships before surfacing, for example.
There are several antennas for communication that can be used for satellite radio in addition to normal radio frequencies. If the boat goes deep under water so that it cannot be reached by conventional means, a towed antenna can receive signals on longitudinal waves . Since only very limited communication is possible due to the extremely small bandwidth of the long-wave signal, the boats are only called to surface to periscope depth, where they can then communicate using conventional transmitters. Each Ohio has two inertial navigation devices to determine its position . For a more precise determination, the data of which is fed into the ICBM just before take-off, there are also systems for receiving satellite navigation data .
Mission profile
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The SSBN of the Ohio class was to maintain the policy of nuclear deterrence built. To do this, the boats drive to designated patrol areas, where they constantly circle around and wait for orders to deploy their nuclear missiles. Since the Ohios are the quietest boats in the US Navy, such trips are carried out without escort by hunting submarines. A patrol lasts two to three months, in the following three to four weeks the ship is in port to enable minor repairs and replenishing supplies. Then a new patrol begins. The first units of the class reached the mark of 50 completed patrol trips after around 15 years of service.
Thanks to the global range of the rockets, the Ohios were not forward deployed like their predecessors, i.e. stationed in forward bases such as Rota in Spain or Apra Harbor on Guam . Instead, the home ports of the boats were on the American mainland from the start. Today the boats of the Pacific Fleet are stationed at Naval Base Kitsap in Washington State and those of the Atlantic Fleet are stationed at Naval Submarine Base Kings Bay , Georgia .
There is particular interest in the SSBN because of their ability to carry nuclear missiles very close to enemy territory. The correspondingly short reaction time of the attacked leads to strategic advantages in the event of a first strike . In addition, the boats are mobile and therefore more difficult to destroy than land-based systems by a first strike by the enemy, which is why they contribute significantly to a second strike capacity. Due to the global range of the rockets, they can also be fired from domestic waters, where the submarines are very safe from attacks by enemy forces. This secured the policy of the balance of horror . Because of this, in 2000 the Ohio carried approximately 50% of the warheads ready for use from the US armed forces.
The new SSGN, on the other hand, can also act as part of combat groups. Their speed of 25 knots allows them to maintain the marching speed of aircraft carrier combat groups and to enrich them with capacities for land attacks. Since the boats are very quiet and therefore difficult to locate, they can also be used to release Navy SEALs within hostile waters. Despite the four torpedo tubes, they are less suitable as hunting submarines because their construction concept means that they are not sufficiently maneuverable. The first war use of one of the boats was Operation Odyssey Dawn in 2011.
crew
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There are around 160 people aboard an Ohio-class submarine on a patrol trip . Of these, between 14 and 17 are officers and around 140 men, of which around 15 are chief petty officers . These three groups have separate quarters as well as their own dining and lounge areas. Crews sleep in three-story bunks , nine men per room, the officers with two or three men per room. Only the commander and first officer can claim their own cabin.
Two complete crews are assigned to each boat. These are named Gold Crew and Blue Crew after the traditional colors of the US Navy, gold and blue . While one of the crews is on patrol, the other goes ashore. Every sailor gets time to be with his family on the one hand, and on the other hand the opportunity to prepare for the next patrol while the boat is still at sea. A seaman always remains permanently assigned to one of the crews for the time of his secondment on an Ohio . The reason for this rule, introduced during the Cold War, is that the boat only has to spend a few days in port for supply and maintenance between two trips and is therefore ready for use again sooner. The SSGN also keep their two-crew routine.
A watch lasts six hours on an Ohio , followed by six hours that can be used for qualification and the like, followed by six hours for sleeping. A day on board only lasts 18 hours, which is possible because the crew cannot see any sunlight anyway; during a standard patrol, the submarine goes underground at the beginning and only reappears immediately before returning to port.
On a normal 60- to 90-day trip, there are around 4,500 liters of fresh milk, 22,000 eggs, 3.5 tons of meat, 400 kg of fish, two tons of potatoes and two tons of vegetables as well as around 400 kg of fruit on board. Most of the food is frozen and prepared in the galley . Fresh water is generated by a water treatment system on board. This is used for cooking, to prepare coffee and for personal hygiene. There are also soft drink machines in the trade fairs. Alcoholic beverages are completely prohibited on board. In order to be able to load all these things in the shortest possible time, each boat has three loading hatches through which supplies can be brought on board on pallets.
Since the boats cannot receive any television signals underwater, around 500 films are carried on each trip. In the case of the SSBN variant, in particular, contact with the families is more difficult for the crew: It is not possible to contact them by phone or the Internet, and since the boats often remain submerged during the entire patrol, it is not possible to transport mail. The relatives are only notified in the event of a planned appearance, for example for a transfer of personnel, so that they can send letters in good time that will be flown onto the rendezvous boat.
literature
- Douglas C. Waller: Big Red: Three Months on Board a Trident Nuclear Submarine. HarperCollins 2001, ISBN 0-06-019484-7 .
Web links
- Official fact file for SSBN and SSGN (English)
- Ohio class on globalsecurity.org (English)
- Ohio class on naval-technology.com (English)
Footnotes
- ↑ Eric J. Labs: The Long-Term Outlook for the US Navy's Fleet ( Memento February 15, 2010 in the Internet Archive ) , Congressional Budget Office, January 20, 2010, p. 11.
- ^ Stefan Terzibaschitsch : Sea power USA. Bechtermünz-Verlag, ISBN 3-86047-576-2 , p. 486.
- ↑ Chris & David Miller: Modern Warships. Verlag Stocker-Schmid, Dietikon-Zürich 1990, p. 135.
- ↑ a b LCDR Bob Aronson and LCDR Mike Woods (CNO Staff): TRIDENT Hull and Missile Life Extensions Approved ( Memento of November 14, 2007 in the Internet Archive ) (engl.)
- ↑ Capt. Norrit, SSGN Program Manager: Transformation Comes to the Fleet ( Memento from November 11, 2007 in the Internet Archive ), report on the SSGN conversion from the US Navy submarine magazine, Undersea Warfare (Eng.)
- ↑ a b For example Globalsecurity.org mentions these numbers
- ↑ Longitudinal section through the trunk on globalsecurity.org (engl.)
- ↑ atomwaffena-z.info: Glossary: Ohio submarine
- ↑ Naval Vessel Register entry of the USS Louisiana ( Memento from July 16, 2016 in the Internet Archive ) (Eng.)
- ↑ a b Statistics on the official website of the USS Alaska . United States Navy, archived from the original on January 15, 2005 ; accessed on August 11, 2013 (eng).
- ↑ a b c Submarine Bob (FAQ) on the side of the USS Alaska . United States Navy, archived from the original on July 26, 2007 ; accessed on August 11, 2013 (eng).
- ^ Andrew Tilghman: Studies could mean end of 18-hour days on subs. (No longer available online.) In: Navy Times. Archived from the original on September 10, 2012 ; accessed on July 30, 2020 (English).
