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Updated July 10, 2024
Navy TAGOS-25 Ocean Surveillance Shipbuilding Program:
Background and Issues for Congress
Introduction
22) that entered service in 1991-1993, and one Impeccable
The Navy in FY2022 procured the first of a planned class
(TAGOS-23) class ship that entered service in 2000. As of
of seven new TAGOS-25 class ocean surveillance ships.
the end of FY2023, all five were homeported at Yokohama,
Under the Navy’s FY2025 budget submission, the Navy is
Japan. The ships use a Small Waterplane Area Twin Hull
proposing to defer procurement of the second TAGOS-25
(SWATH) design, in which the ship’s upper part sits on two
class ship from FY2025 to FY2026. The Navy’s proposed
struts that extend down to a pair of submerged, submarine-
FY2025 shipbuilding budget requests no FY2025
like hulls (Figure 2). The struts have a narrow cross section
procurement funding for the TAGOS-25 program.
at the waterline (i.e., they have a small waterplane area).
The SWATH design has certain limitations, but it has
Meaning of TAGOS Designation
features (including very good stability in high seas) that are
In the designation TAGOS (also written as T-AGOS), the T
useful for SURTASS operations.
means the ships are operated by the Military Sealift
Command (MSC); the A means they are auxiliary (i.e.,
Figure 2. USNS Effective (TAGOS-21) in Dry Dock
support) ships; the G means they have a general or
miscellaneous mission; and the OS means the mission is
ocean surveillance.
TAGOS Ships in the Navy
TAGOS ships (Figure 1 and Figure 2) support Navy
antisubmarine warfare (ASW) operations. As stated in the
Navy’s FY2025 budget submission, TAGOS ships “gather
underwater acoustical data to support the mission of the
Integrated Undersea Surveillance System (IUSS) by
providing a ship platform capable of theater anti-submarine
acoustic passive and active surveillance.… The two current
classes of [TAGOS] surveillance ships use Surveillance
Towed-Array Sensor System (SURTASS) equipment to
gather undersea acoustic data.” Figure 3 shows a simplified
diagram of a TAGOS-25 ship with its SURTASS arrays.
Source: U.S. Navy photograph 070913-N-2638R-004 posted at
Figure 1. USNS Impeccable (TAGOS-23)
Wikimedia Commons, accessed May 25, 2021.
Figure 3. TAGOS Ship with SURTASS Arrays
Source: U.S. Navy photograph accompanying “Ocean Surveil ance
Source: Detail from slide 13, entitled “TAGOS(X) Concept of
Ships,” Military Sealift Command, accessed May 25, 2021.
Operations (CONOPS),” in Industry Day briefing for TAGOS(X)
program, June 26, 2019, accessed May 26, 2021, at GovTribe.com.
Current TAGOS Ships
The Navy’s five aging TAGOS ships include four
Victorious (TAGOS-19) class ships (TAGOS 19 through
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Navy TAGOS-25 Ocean Surveillance Shipbuilding Program: Background and Issues for Congress
TAGOS-25 Program
million to procure—an increase of $355.2 million, or
81.8%, from its previously estimated cost. The Navy’s
Quantity, Schedule, and Design
FY2024 budget submission stated that this cost growth is
The Navy wants to procure seven TAGOS-25 class ships as
“due to several factors affecting shipbuilding prices
replacements for its five in-service TAGOS ships. The first
including direct material inflation, supply chain challenges,
TAGOS-25 class ship was procured in FY2022. Under the
and increased non-recurring engineering costs.”
Navy’s FY2025 budget submission, the Navy wants to
procure the second through fifth ships in the class in
Contract Award
FY2026-FY2029 at a rate of one ship per year. The Navy’s
On May 18, 2023, the Navy announced that it had awarded
notional design for the TAGOS-25 class (Figure 4)
Austal USA, a shipyard in Mobile, AL, a $113.9 million
employs a SWATH design that would be larger and faster
fixed-price incentive (firm target) and firm-fixed-price
than the in-service TAGOS ships (see Table 1).
contract for detail design of the TAGOS-25 class. The
contract includes options for the detail design and
Figure 4. Notional Navy Design for TAGOS-25
construction of up to seven TAGOS-25s plus associated
work. Exercising the options would bring the cumulative
value of the contract to about $3,195.4 million (i.e., about
$3.2 billion). The Navy stated that it received two offers
(i.e., Austal’s offer and one other offer).
On May 30, 2024, the Navy awarded Austal USA a $516
million contract modification, exercising an option for long-
lead time material and detail design and construction
(DD&C) of the first ship in the class.
Issues for Congress
Potential issues for Congress include the reasons for the
Source: Artist’s rendering accompanying press released entitled
81.8% cost growth on the first ship in the class, the risk of
“Halter Marine Secures Contract for Industrial Studies for T-AGOS
further cost growth on the first ship, why the Navy wants to
Program,” Halter Marine, July 20, 2020.
defer the procurement of the second ship from FY2025 to
FY2026, and why the Navy in its FY2025 budget
Table 1. TAGOS Ship Designs
submission appears to have increased the estimated
procurement costs of the sixth and seventh ships in the class
TAGOS-
TAGOS-
TAGOS-25
(which are to be procured after the FY2026-FY2029 Future
19
23
(notional)
Years Defense Plan [FYDP])—but not those of the second
through fifth ships in the class (which are to be during the
Length
235 feet
282 feet
356 feet
FYDP)—to figures that appear consistent with the cost
Maximum speed
10 knots
13 knots
20 knots
growth and resulting estimated $789.6 million procurement
cost of the first ship in the class.
Displacement
3,384 tons
5,370 tons
8,500 tons
Accommodations
~48
54
68
Procurement Funding
The Navy’s proposed FY2025 shipbuilding budget requests
Sources: “Ocean Surveil ance Ships - T-AGOS,” U.S. Navy, and (for
no FY2025 procurement funding for the TAGOS-25
TAGOS-25) slide 22, entitled “T-AGOS Class Comparison,” from
program. The House Armed Services Committee, in its
Industry Day briefing for TAGOS(X) program, June 26, 2019,
report (H.Rept. 118-529 of May 31, 2024) on the FY2025
accessed May 26, 2021, at GovTribe.com.
National Defense Authorization Act (NDAA) (H.R. 8070),
and the House Appropriations Committee, in its report
The Navy’s desire to replace the five in-service TAGOS
(H.Rept. 118-557 of June 17, 2024) on the FY2025 DOD
ships with seven larger and faster TAGOS-25s can be
Appropriations Act (H.R. 8774), recommended no FY2025
viewed as a response by the Navy to the submarine
procurement funding for the TAGOS-25 program. Section
modernization efforts of countries such as China and
8094 of H.R. 8774 continues U.S. content requirements for
Russia. For more on China’s submarine modernization
all TAGOS-25 auxiliary equipment, including pumps and
effort, see CRS Report RL33153, China Naval
propulsion shafts.
Modernization: Implications for U.S. Navy Capabilities—
Background and Issues for Congress, by Ronald O'Rourke.
Ronald O'Rourke, Specialist in Naval Affairs
Procurement Cost
IF11838
The Navy estimates in its FY2024 and FY2025 budget
submissions that the first ship in the class will cost $789.6
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Navy TAGOS-25 Ocean Surveillance Shipbuilding Program: Background and Issues for Congress
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