Advanced Attack Submarine

Here Is the Advanced Attack Submarine the U.S. Navy Never Built

The submarine, never built, would have been smaller than other subs and a mothership to drones.

By Kyle Mizokami

 H.I. SUTTON

A previously unpublicized design for the U.S. Navy shows an advanced attack submarine that could operate unmanned undersea vehicles remotely and conduct “spy” missions on the seabed floor. The unnamed design was never built, but it could hint at the future direction of the U.S. submarine fleet.



Sub 2000, as seen in Undersea Warfare magazine.
U.S. NAVY

The sub design was discovered by open source intelligence Twitter account Intellipus and published online by researcher and author H.I. Sutton, author of the Covert Shores submarine blog and World Submarines: Covert Shores Recognition Guide. A mockup of the design was featured in a 2000 magazine article written by Rear Admiral Malcolm Fages. At time of publication Adm. Fages was the U.S. Navy's director of the Submarine Warfare Division.

The proposed submarine is a radical break from previous U.S. submarine designs, which mostly resemble cylinders with rounded ends, a large sail, and a propulsion system at the stern. The design—let’s call it “Sub 2000”—was much flatter and organic in appearance. The sail was much shorter and blended into the length of the hull, which had a flattened bottom. Unlike the current t-shaped tail fins of U.S. Navy subs, Sub 2000 had an “x” shape not unlike Japan’s Soryu-class diesel electric attack submarines.


Japan Maritime Self Defense Force submarine Hakuryu--note the two tail fins protruding from the water, evidence of the tail’s x-shaped configuration.
MASS COMMUNICATION SPECIALIST 2ND CLASS MICHAEL H. LEE

Sub 2000 is strange in other ways. At just 262 feet long, the design is markedly smaller than the current 377-foot-long Virginia-class nuclear powered attack subs. The sub features a double hull, which, as H.I. Sutton explained to Popular Mechanics, “means that the steel tube which houses the crew is completely encased in a second outer hull. US Navy submarines haven't had true double hulls since the 1950s, so this is a break from the norms.”

The pumpjet propulsion system is encased within the hull instead of sitting in a bulb-shaped basket at the stern. “The most sensitive feature is likely to be the completely encased pumpjet propulsion,” Sutton said. “This might contribute to making it much quieter than other submarines. In underwater warfare stealth is mainly about being quiet and pumpjets are an advantage that U.S. and British submarines had for many years. Now Russia uses pumpjets also.”


H.I. SUTTON

The sub is heavily armed for its size. Instead of a typical bank of torpedo tubes in the nose or flanks of the ship, it has two sets of three torpedo tubes in pop-open launchers. The launchers are completely flush with the sides of the submarine when not in use, streamlining the submarine for quiet operation. Sub 2000 also has twelve vertical launch silos for cruise missiles and other payloads.

Sub 2000 would have operated as a typical attack submarine but with the ability to conduct specialized underwater espionage missions. The x-shaped tail fin array is typically associated with submarine designs meant for operating in shallow water areas relatively close to shore, allowing the submarine to operate closer to the sea bottom while minimizing the chance of damage to its tail fins. The configuration is also useful for sitting on the seabed while conducting missions. Sub 2000 could sit on the seabed off an enemy coastline planting listening devices, tapping undersea cables, or quietly listening to electromagnetic transmissions.

Sub 2000 also has two unmanned undersea vehicles (UUVs) that attach behind the sail. According to Sutton,”(this) reinforces the suggestion that this design was intended as a replacement for USS Parche, the most decorated US submarine in history. Parche conducted espionage missions during the Cold War and after.”


USS Jimmy Carter.
U.S. NAVY PHOTO BY LT. CMDR. MICHAEL SMITH

The U.S. Navy never did built Sub 2000, although it did build the USS Jimmy Carter, a Seawolf-class attack submarine with a hull extension to allow it to perform espionage missions. Jimmy Carter effectively replaced Parche. Although the U.S. Navy is busy building the more conventional Virginia-class submarines, it might fold features from Sub 2000 into a next-generation attack submarine.