LHA-1 Tarawa class Upgrades
As completed, they carried two Mk 25 Mod. 1 BPDMS launchers for Sea Sparrow SAMs, controlled by two Mk 71 directors with Mk 115 radars, and three 5"/54 DP guns. The Sea Sparrow launchers and the port aft 5"/54 gun were removed from all during the early 1990s, and the remaining two gunmounts were deleted during 1997; the associated SPQ-9A surface-fire control radar and SPG-60 AA fire control radar have thus far been retained, however. The 5"/54 guns were provided primarily to provide shore fire support, a function no longer foreseen under current amphibious landing tactics, and they could also be used for AA. Six single 20-mm AA guns have also been removed.
Planned addition of bulbous bow was canceled, as was deletion of the boat crane.
As of October 1994, LHA class ships were outfitted with the SPS-40E air search radar, the MK 23 target acquisition system, and the SLQ-32 electronic warfare system as detection elements. Also, installation of the SPS-48E radar was complete on three ships. Control functions were performed by the SWY-2 integrator, which interfaced the MK 23 target acquisition radar with the RAM Block 0 weapon system. Engagement elements included RAM Block 0, Phalanx Block 0, and the MK 36 decoy launching system. This defense configuration produced a performance result that was below the capstone requirements for the class.
Since October 1994, Navy staff made only a few defensive improvements to the LHA class. Specifically, they completed installations of the SPS-48E radar and the Phalanx Block 1 on all five LHA ships. In addition, they installed the Advanced Combat Direction System Block 0 on three ships. All LHA class ships have received two Mk 49, 21-cell RAM point defense missile launchers, starting with LHA 5; the Mk 49 launchers are sited to port atop the pilothouse and to starboard at the aft end of the flight deck and are controlled by the SWY-2 weapons-control system. LHA 1 completed overhaul in 1995 with RAM launchers, Mk 23 TAS target designation radar, and SPS-48E 3-D radar in place of SPS-52B, a modification now accomplished in all, by using sets taken from retired CG 16 and CG 26 class cruisers. All have had original WLR-1 EW suite replaced by SLQ-32(V)3 and URN-20 TACAN replaced by URN-25.
These improvements, however, provided little overall improvement in the class's ability to meet the capstone requirements. The ships of this class are no longer scheduled to receive the SSDS (Ship Self-Defense System) Block 1 update.
The Tarawa class ships (LHAs) are vintage amphibious assault ships. Between 2011 and 2015 one ship annually will reach the end of their service life. Maintaining twelve "big deck" amphibious ships is necessary to fulfill the 12 ARG QDR requirement and to satisfy Marine Corps lift requirements. The Marine Corps has conducted a Development of Options Study to determine the best course to meet naval requirements. The options are: an LHA Service Life Extension Program (SLEP); an LHD Mod; or a new construction LH(X) variant.
In October 1998, the Navy considered implementing a Service Life Extension Program (SLEP) overhaul on the Tarawa class amphibious assault ships when they reach the 35 year point in their operating life. However, there are no current plans to do so. The SLEP would provide another 15 years of life at a cost of nearly $1.0 billion per SLEP. The SLEP would extend the machinery operating life and provide communications upgrades. However, stability would remain a main concern and the LHA has limited capabilities to support 21st century littoral warfare systems such as the landing craft air cushion (LCAC) and MV-22 Osprey tilt-rotor aircraft. Some observers have argued that the SLEP option could be less cost-effective than procuring a new ship, because it would extend the life of the ships by about 15 years (less than half the life of a new ship) but could cost about $1 billion per ship (more than half the cost of a new ship).
The Congress has supported procurement of long lead materials for the construction of LHD-8 in lieu of a future SLEP for LHA-1. The LHA can transport one LCAC when the LCAC is placed in the well deck sideways, while the Wasp class amphibious assault (multipurpose) (LHD) ship carries two LCACs which drive in and drive out of the well deck fully loaded. The LHD has 20,000 more cubic feet storage capacity but 5,000 square feet less vehicle storage than an LHA. The LHD has more hangar and deck space than an LHA giving the LHD the capacity to carry three more CH-46 helicopters than the LHA. A Marine Expeditionary Unit (MEU) with an LHA as the large deck amphibious ship requires three additional ships to provide the capabilities required of an MEU. When an LHD is the large deck amphibious ship in the MEU, one to two fewer ships are needed to support the MEU. In the view of the Senate, replacing the LHA with an LHD would provide a platform with the capability to support 21st century requirements. The service life estimate for a LHD is 35 years while the LHA SLEP will add an additional 15 years of life. From a force capitalization perspective, the Navy will have 20 more years of ship life at a drastically reduced procurement cost per year of life by building the LHD instead of performing a SLEP on the LHA.
Beginning in fiscal year 2001, the Navy began an analysis of alternatives study to determine the preferred choice between a modification to the LHD class design or a brand new hull configuration, known as the LH(X) class.
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