Why the USS Paul F. Foster Was Chosen as the Navy’s Self Defense Test Ship

When the USS Paul F. Foster (DD-964) completed her service as a fleet destroyer, the U.S. Navy selected her for a unique second career as the Navy’s Self Defense Test Ship (SDTS). The choice was not accidental. The Spruance-class destroyers, including the Paul F. Foster, possessed several characteristics that made them ideal for this important mission.

A Modern and Reliable Design

The Spruance-class destroyers represented a major leap forward in naval engineering when they entered service in the 1970s. Designed during the Cold War, they were built with advanced propulsion systems, modern combat systems, and large, adaptable internal spaces.

These features made them well suited for long-term service and adaptable enough to support evolving technologies. Their reliability and modern design made them excellent candidates for continued use even after leaving fleet service.

Gas Turbine Propulsion

One of the most important innovations of the Spruance class was the use of gas turbine propulsion instead of traditional steam plants. The ships used four General Electric LM2500 gas turbines, providing excellent reliability and fast response.

Gas turbines provided several advantages:

Faster startup and shutdown times
Simplified engineering systems
Reduced maintenance requirements
Improved operational reliability

These characteristics made the Spruance-class destroyers easier to operate and maintain compared to earlier steam-powered ships.

Additional Electrical Power – The Fourth GTG

Another factor that made the USS Paul F. Foster particularly valuable as a test platform was the installation of an additional electrical generator.

During her service life, the ship received ShipAlt DD-964-452K, which installed a fourth Gas Turbine Generator (GTG). This modification significantly increased the ship’s electrical generation capacity.

Additional electrical power is extremely important for a test ship because many modern naval systems—including sensors, instrumentation, and experimental equipment—require substantial and reliable electrical power.

With the additional GTG, the Paul F. Foster had greater electrical capacity than a standard Spruance-class destroyer, making her especially well suited for supporting engineering tests and new technologies.

Spacious Internal Layout

Spruance-class destroyers were known for their large hull size and generous internal space. This allowed engineers to modify and adapt the ship to support testing equipment, instrumentation, and engineering systems.

The extra space made it possible to install new systems while still maintaining the ship’s stability and operational capability.

Proven Seakeeping Ability

The Spruance class was widely respected for its excellent seakeeping qualities. The ships were able to operate effectively in rough seas while maintaining stability for sensors, equipment, and engineering systems.

For a ship conducting testing and evaluation at sea, this stability is extremely valuable.

A Strong Structural Platform

The size and structural strength of the destroyer also made it well suited for long-term testing programs. The ship could support new equipment installations, modifications, and instrumentation while continuing to operate safely at sea.

A Destroyer That Continued to Serve

Because of these advantages, the Navy selected USS Paul F. Foster to become the next Self Defense Test Ship following the retirement of earlier test platforms.

Redesignated EDD-964, the ship was modified to support a wide range of engineering and technology evaluation missions. In this role, she has continued serving the Navy long after her original fleet service ended.

A Unique Legacy

Few warships continue serving long after their operational careers end. The USS Paul F. Foster is one of those rare ships.

For the sailors who served aboard her, it is a source of pride to know that the ship continues contributing to the advancement of naval technology and the safety of future sailors.

Even decades after her commissioning, the Paul F. Foster remains an important part of the Navy’s story. ⚓