Lafayette class

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The John C. Calhoun of the Madison subclass 1991
The John C. Calhoun of the Madison subclass 1991
Overview
Type Missile submarine
units 31 built, 0 in service
Namesake General Marie-Joseph Motier, Marquis de La Fayette
period of service

1963 to 1995

Technical specifications
displacement

8250 ts submerged

length

129.5 m

width

10.1 m

Draft

9.6 m

crew

13 officers and 107 men

drive

1 × S5W reactor

speed

30+ knots

Armament

4 × 533 mm torpedo tube
16 SLBM

The Lafayette-class was a class of nuclear-powered missile submarines (SSBN) operated by the United States Navy .

Since the design was still changed during construction, the last ten of the 19 units are rarely listed as a separate James Madison class . The boats of the Benjamin Franklin class have also been only slightly modified, but are run as a separate class by the Navy. All boats in the three groups had identical hulls. This is why the Benjamin Franklin class is also regarded as the second subclass of the Lafayette class in the relevant specialist literature .

history

Planning and construction

Kamehameha on the launch

The Lafayette class was a development from the previous Ethan Allen class , the first specially designed and built nuclear submarine class for the underwater launch of submarine-launched ballistic missiles (SLBM), i.e. submarine-supported nuclear missiles . The George Washington class in front of it was created by converting hunting submarines. At the beginning of 1961, the first unit of the Lafayette class was laid down, and 18 more followed by the end of 1962. After nine units, the design was changed slightly, the units from the tenth boat carried more modern missiles from the beginning, which is why these ten units are rarely referred to as the James Madison class .

The first 19 boats of the class were built in three naval shipyards and a special shipyard for submarines, which explains the short overall construction time. These shipyards were the submarine specialized Electric Boat ( EB ) for seven boats, Newport News Shipbuilding ( NNS ) for six, the Mare Island Naval Shipyard for four Lafayettes and the Portsmouth Naval Shipyard for two boats. The cost of building these boats was around $ 110 million each.

The following twelve units of the submarines, officially designated as the Benjamin Franklin class , differed only slightly from the Lafayette class . They were built between 1963 and 1966 at the shipyards of EB (seven), NNS (four) and Mare Island. Only the drive system was designed for a quieter ride.

The boats were named after historical politicians from the history of the United States as well as famous military men. The type ship Marie-Joseph Motier, Marquis de La Fayette , honors the first units of the two subclasses, the US President James Madison and the founding father Benjamin Franklin . With Friedrich Wilhelm von Steuben , a native German was also given the honor of naming patronage.

Modifications

James K. Polk with two DDS behind the tower

Between 1970 and 1977 the first 19 boats of the Lafayette class were converted from their older missiles to more modern ones, and in the following years selected boats of the class were modified again (see section armament ).

Two Franklins were converted for special operations in the early 1990s. The rocket launchers were deactivated and brackets were installed to transport dry deck shelters . This allowed the boats to serve as a platform for the undetected dropping or picking up of United States Navy Seals . These were the USS James K. Polk (SSBN-645) , which was decommissioned in 1999, and the USS Kamehameha (SSBN-642) , which was in service until 2002.

One Lafayette and one Madison each were converted into a Moored Training Ship , or MTS for short , and are used to train personnel on the pier. The USS Sam Rayburn (SSBN-635) should serve this role until 2014, while it is unclear how long the USS Daniel Webster (SSBN-626) will continue to function as such.

period of service

The 19 boats of the Lafayette and James Madison class were put into service in 1963 and 1964, the twelve Franklins from 1965 to 1967. Together with the boats of the George Washington class and the Ethan Allen class , the boats made up the majority the so-called 41 for Freedom , the 41 SSBN, which represented America's nuclear force on the oceans. In 1972 the SALT-I treaty limited the number of SSBNs used by the US Navy to 44 units. In 1981 the first Ohio-class boat was put into service and the first boats, mainly the George Washington and Ethan Allen classes , began to be withdrawn from service.

The first decommissioning of a Lafayette took place in 1986, another in 1987. From 1989 onwards, boats were decommissioned every year until 1995 no longer any boat of the class was active in its original role as a missile submarine. The Franklins were the last to be deactivated between 1992 and 1995, with the exceptions mentioned above. The normal service life of a submarine is 30 years, but only a few of the 31 boats reached this; especially because after the end of the Cold War the importance of nuclear deterrence took a back seat .

technology

hull

Good view of the hull

The hull of all units was 129.5 meters long and 10.1 meters wide, the draft was 9.6 meters. The submarines displaced 8,250 ts submerged  . The launch shafts for the 16 ICBMs were located behind the tower in a clearly visible "hump". The fore elevator was attached to the tower, only with the Daniel Webster an experimental second small tower was attached to the bow, on which the elevator was. Since this device reduced the speed, it was removed again after a few years.

Inside, the boats are divided in a similar way to hunting submarines. In front of and under the tower there are torpedo, crew and command rooms, behind first the rocket shafts (called Sherwood Forest ) and aft the reactor chamber and then the engine room.

drive

The drive of the Lafayettes consisted of a pressurized water reactor of the type S5W . The S stands for the use on a certain type of ship, here submarine , submarine, the 5 stands for the generation, the W represents the manufacturer, with this type the Westinghouse Electric Corporation . This reactor, which was originally designed for the smaller Skipjack-class fighter submarines , delivered around 15,000 horsepower that acted on a wave. The maximum submerged speed was 20 knots or less, a few knots slower than hunting submarines. However, a quiet drive system counts more than speed for the SSBN, as they primarily have to drive deterrent patrols that cannot be monitored by potential opponents.

In the boats of the Benjamin Franklin sub-class, important parts of this propulsion system were stored on so-called “rafts” so as to be shock-proof. As a result, fewer vibrations were transmitted into the water, which further reduced the detectability.

Armament

Sam Rayburn with the rocket
shafts open

When they were commissioned, the boats carried the UGM-27 Polaris in various designs. The first nine units were designed at the beginning to ballistic missiles of the type UGM-27B Polaris A2 to start, while the last 22 boats ( James Madison and Benjamin Franklin class ), the modernized UGM-27C Polaris A3 wore, where the range has been increased by more than 50% to 2500 nautical miles compared to the A2. Between 1970 and 1977, the improved UGM-73 Poseidon was introduced on all 31 boats . Here the range was up to 3300 nautical miles and reached the range of land-based ICBMs for the first time. The conversion cost around 2.3 million US dollars in 1970, but in the stagflation phase only four years later it was already over 31 million dollars. It increased the operational flexibility and fighting power of the converted boats considerably and extended their range of modernity until they were replaced by the late Ohio class .

In addition, the Navy decided in 1976 to equip twelve boats of the class for the modern UGM-93A Trident I (C4) after it had been determined that the development of the new SSBN class, the Ohio class , would be significantly delayed. The Trident I (C4) was ready for use from 1979, but the type ship USS Ohio (SSBN-726) did not enter service until the end of 1981. In July 1979 the fifth test launch of converted, submerged Lafayettes took place, on October 20, 1979 the USS Francis Scott Key (SSBN-657) began the first patrol voyage with the Trident . The Trident was the direct successor similar in size to Poseidon , but an even larger range of around 4,000 nautical miles.

The rockets were carried in vertical launch shafts behind the tower, regardless of the version, a boat could carry a total of 16 rockets.

For self-defense, the Lafayettes had four torpedo tubes , from which not only torpedoes but also the UUM-44 Subroc could be ejected.

electronics

The location electronics were largely taken over from the Skipjack hunting submarines. In the bow was the sonar system BQS-4 , which could be used both actively and passively to track down enemy submarines. So-called BQR-7 lateral sensors , which were used passively to determine the bearing of targets , also ran along the hull. A short-range active sonar of the type BQR-19 was used for navigation . Was added over the Skipjacks only a passive working towed array sonar type BQR-15 .

To determine the position, which was fed in addition to the use for navigation as shooting data to the missile, there was on board three inertial navigation systems of the type SINS Mk. 2, .

Mission profile

The Lafayettes formed the bulk of the United States' deterrent force on the oceans. With 16 SLBM on board, a boat left its home port under strict safety precautions. Hunting submarines and destroyers ensured that the waters around the harbor were clear of enemy submarines so that the SSBN could safely depart. The Lafayette then remained submerged for up to three months without interruption and were in a certain patrol area that was subject to the highest level of secrecy. After the patrol, the boats returned to the base, changed crew (each boat had two complete crews, referred to as Blue and Gold respectively), and after a repair period returned to the depths of the ocean with the second crew.

Before the introduction of ICBMs ( Trident ) with their significantly increased range, many of the boats were stationed for years on forward bases, for example on the Atlantic bases in Holy Loch , Scotland and Rota , Spain as well as on bases in the Pacific Apra Harbor , Guam and Pearl Harbor , Hawaii.

Web links

Commons : Lafayette class  - collection of images, videos, and audio files
Commons : James Madison Class  - collection of pictures, videos, and audio files
Commons : Benjamin Franklin Class  - collection of pictures, videos, and audio files

Footnotes

  1. a b Terzibaschitsch: Sea power USA. Bernard & Graefe Verlag, Bonn, ISBN 3-86047-576-2 , p. 489.
This version was added to the list of articles worth reading on November 8, 2007 .