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THE SC-21 COEA PROGRAM

By the time the Soviet Union collapsed in 1991, the USN no longer had to worry about defending trans-Atlantic convoys, bombing Murmansk, or sending the world into a nuclear winter. Peace was finally at hand, and old Cold War tensions and doctrines began to die. With the dawn of the next century less than a decade away, the USN envisioned itself as a mix of green and blue water vessels that could take on a resurgent Russia or bombard rogue states into dust. By 1994, this way of thinking gave way to the SC-21 COEA study.

The Surface Combatant for the 21st-century program kicked off in 1994 with authorization to formulate and design several new warships to meet various roles and ideas, while combining them with the latest and future technologies. These ship concepts were divided into three categories:

Concept 1: Upgrades to existing ships, most likely the Virginias, Spruances, Kidds, and Perrys.
Concept 2: New designs off existing hulls, most likely the Burke and what would become the San Antonio LPDs. Think of these as the Burke helicopter carriers or the BMD cruiser version San Antonio.
Concept 3: Entirely new hulls that would utilize new technology.

While we have no information on what was proposed in Concept 1 or 2, we do know that Concept 3 was broken into various subcategories that revolve around a general idea, technology, or mission. These categories were:

3A: Large and abstract stealth warships, the most famous being the Arsenal Ship concept and the 3A3 Amphibious Cruiser.
3B: Stealth warships designed specifically to bombard coastal targets. The only known vessel from this group is the 3B1 Littoral Combatant, which grew into the DD(X) program, and eventually, into the oversized port decoration, we now call the Zumwalt.
3C: Mostly budget stealth escort vessels and frigates.
3D: Modular warships, the oddest example being some vessels with a modular BMD system. If you thought the mission modules on the LCS were a disaster, oh boy, you won’t like these!

So in summary, this is the complete list of known SC-21 concepts:

3A1 - Power Projection Ship - 12,500-ton cruiser, advanced radar, 254 Mk 41 VLS cells, small hanger
3A2 - Aviation Cruiser - 23,500-ton cruiser, advanced radar, 254 Mk 41 VLS cells, up to 12 helicopters
3A3 - Amphibious Cruiser - 25,000-ton cruiser, advanced radar, 254 Mk 41 VLS cells, and a well deck for amphibious craft
3A4 - ???
3A5 - Arsenal ship with limited self-defense capability
3A6 - Arsenal ship with no self-defense capability
3B1 - Littorial Combatant - Lead to the Zumwalt-class DDG
3C1 - Maritime Combatant - 5,500-ton 61-cell stealth Spraunce replacement
3C2 - ???
3C3 - Armed Foam Tanker - Concept to have a warship capable of absorbing lots of damage
3C4 - Small ASW Combatant "essentially a frigate with medium-range anti-ship capability"
There was also something in the 3C branch called the "Agile Maritime Patrol Ship (for area AAW and ASW, with 64 vertical launch cells, naval gunfire support capability, and an armed helicopter)"
3D1 - Expeditionary Force Support Ship - Modular Warship
3D2 - Tailored Maritime Support Ship/FMLAC - 4,000-ton stealth Perry replacement - "A Tailored Maritime Support Ship (3D2) would have fewer modules: 32-cell vertical launchers (Originally the Mk 41, but then switched to the Mk 48), area AAW, medium fire support, special operations."

Ultimately a select few of these concepts would be pushed into the next stage of development, with the ultimate goal of developing the optimal surface combatant for the 21st Century.
I don’t know where I first came across the SC-21 (probably browsing Wikipedia), but I always regarded it as this mysterious program that I knew nothing about. Google could turn up very little, further hampering my search. I came in contact with SebastianP on the Shipbucket Discord, and I eventually brought the topic up. It spiraled into several hour-long conversations trying to identify what every study was, and what the program was as a whole. Without him, none of this would be possible so a big thank you to him.

The topic would come up several more times, and I eventually decided that I want to draw a new frigate for my AU (which will likely never materialize). I really wanted the frigate to be based on the 3C1 study, but I needed to start somewhere! I asked SebastianP for a scan of Friedman’s US Destroyers Revised Edition, and here we are now.

SC-21 COEA STUDY 3C1 MARITIME COMBATANT

SC-21 COEA Study 3C1 Maritime Combatant is little more than a stealth Spruance replacement with AEGIS. It’s a very sleek-looking ship that reminds me of all those stealth European frigates.
The ship is armed with a 5”/62 gun, a 64-cell VLS, and a single helicopter. It also features a new electric propulsion system, powered by various new engines and turbines. The main mast houses a 12-foot phased array air-search radar (my guess is this became the SPY-4 VSR), and something called the “MFAR”. This is essentially a phased array version of the SPG-62, SPS-67, and SPQ-9. The reference drawing shows it smaller than the air-search set, and seeing that the SPY-6 on the FFG(X) is a 6-foot system, my guess is the MFAR is also 6-feet.

The ref drawing is very vague on details, so I had to speculate most of it.
To preserve the stealth profile of the ship, I have put all the mooring gear in little hatches in the hull. A arrangement is found on the Zumwalt.
It is also interesting to note the ref does not list CIWS, torpedo tubes, decoys, or even communication equipment or an RHIB. I have elected to not use any of this stuff in my drawing, with the exception being the massive RHIB door and the select few SATCOMs scattered around the superstructure. These are all speculative, and should not be regarded as accurate.

Dimensions:
Length at Waterline: 480.7 feet (146.5 meters)
Length Overall: 497.3 feet (151.6 meters)
Beam at Weatherdeck: 65.3 feet (19.9 meters)
Draft: 18.4 feet (5.6 meters)

Displacement:
Light Displacement: 6,137 US Tons (5,566.4 metric tons)
Loaded Displacement: 7,948.1 US Tons (7,210.4 Metric Tons)

Armament:
1 x Mk-45 5”/62 gun in a stealth turret
1 x 64-cell Mk-41 VLS for various missiles

Electronics:
4 x 12’ Air-Search Phased Array Radars
*Likely SPY-4
4 x MFAR Missile Illuminators, Gunfire Control Radars, and Surface Search Phased Array Radars
*Likely SPY-3
Speculative size of 6-feet
4 x WSC-6 SATCOMs (Speculative)
1 x TACAN (Speculative)
1 x Unknown Hull-Mounted Sonar Dome
*I just drew a generic sonar dome, it's not supposed to represent any particular system.

Aviation:
Helipad and Hanger Space for One (1) SH-60

Propulsion and Machinery:
29,040 SHP
At Least One (1) Shaft (Likely Two (2)
17,101.3 HP Per Shaft

Now, for the ship herself (sorry for the long-winded post !):



Despite this being one of the most level-headed designs of the entire SC-21 program, it ultimately lost funding when the entire program was scrapped in 2003. Instead of having a useful blue-water combatant that could be used in a multitude of different roles, we got the 3 billion dollar port decorations that don’t even have functional guns. One can only hope in a separate universe, the Zumwalt class is a 7,000-ton ship with a 61-cell VLS and a regular 5” gun.

Questions, comments, and suggestions are welcome as always!

Sources:
SebastianP
Norman Friedman's U.S. Destroyers: An Illustrated Design History, Revised Edition

My reference image can be found here: https://cdn.discordapp.com/attachments/ ... nknown.png

Edit 1: I posted the wrong images.....

Nice work!

For sonar I'd suspect it would have been SQS-53 which is what the 3As were stated to have or alternatively AN/SQS-60 which is what Zumwalt was fitted with.