LPD 17 Flight II
LX(R) / LSD(X) Landing Ship, Dock
The Navy awarded the detail design and construction contract for LPD-29 to Huntington Ingalls Industries (HII) on 16 February 2018. Eleven San Antonio class ships had been delivered, the most recent being USS Portland (LPD 27), which was commissioned April 21, 2018. LPD-28 and 29 would serve as transition ships to LPD-30, the first ship of the LPD 17 Flight II class. LPD Flight II class ships will be the replacement for the Navy's aging LSD 41/49 class ships.
There are several benefits to using the San Antonio-class design as the basis for the next dock landing ship LSD(X) / LX(R):
- The design cost is reduced by not having to create an all new design.
- Construction costs are reduced by capitalizing on the learning curves of the San Antonio-class.
- Funding for the 12th San Antonio-class had already been appropriated, and building the 12th ship and keeping the line open until the LSD(X) begins reducing the production gap between the two programs improves the learning curve for the LSD(X).
Little is known about the LSD(X) other than that it is intended to replace the LSD-41 Whidbey Island and LSD-49 Harpers Ferry classes of dock landing ships. The first LSD(X) will not be authorized until 2020, with an expected commissioning date of 2024, when the first LSD-41 will reach the end of its notional 40-year service life. Development and procurement of the LSD(X) are too far in the future for the Navy to have considered in any detail what characteristics and capabilities it wants the ship to have. The Navy's long-term shipbuilding report envisioned procuring 12 of the ships between 2020 and 2031 at an average cost of about $750 million. CBO does not know what characteristics, such as dimensions or displacement, were used in making that estimate.
For the purposes of this analysis, CBO assumed that the LSD(X) would reflect the growth in size that new amphibious ships have exhibited over the past several years relative to previous classes. A weighted average of the growth in ship displacement from the LHD-8 to the LHA(R) and from the LPD-4 class to the LPD-17 suggests that the LSD(X) would be about 30 percent larger than the LSD-41 and LSD-49 classes. Thus, CBO assumed that the LSD(X) would displace about 15,000 tons at light load and 22,000 tons at full load (versus 12,000 tons at light load and 16,000 to 17,000 tons at full load for the LSD-41 and LSD-49 classes).
CBO assumed that the Navy would use the additional space in the LSD(X) to carry 30 percent more troops and vehicles than on the LSD-41 class, to compensate for the Navy's shortages of lift in those categories relative to the amphibious-lift goal. The LSD(X) would carry the same amount of cargo and the same number of landing craft as the LSD-41 class. In comparison, the LPD-17's displacement is more than 45 percent greater than that of the LPD-4 class and results in twice the vehicle square and LCAC spots as well as in six air spots instead of four. The average cost for 12 LSD(X)s would be about $1.2 billion each, CBO estimated, based on the cost per thousand tons of the LHD-8 and the LPD-17 class.
One of the difficulties, however, in determining the Navy's and Marine Corps's plans for dock landing ships is that the services are still developing concepts for the future composition and employment of amphibious forces. For example, current plans would have each expeditionary strike group include a large amphibious assault ship (such as an LHD or LHA(R)), an LPD-17, and an LSD class ship. But the Navy is also considering a formation in which each expeditionary strike group would include an LHD, an LHA(R), and an LPD-17. In that case, the LSD(X) program would never be started, and existing LSDs would be retired without replacement. The Navy and Marine Corps are still debating the merits of that formation. One problem is that unless the Navy cut the number of expeditionary strike groups, using such a formation would cost more than the Navy's existing plan.
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