Welcome To The Official Website For The
Submarine Development Squadron TWELVE
Submarine Development Squadron TWELVE is located in building 3 at
Naval Submarine Base New London. Squadron TWELVE is tasked as
tactical development authority for Submarine Forces Atlantic and Pacific.
This is a unique responsibility which is dedicated to the formulation and
improvement of submarine tactics and to the measurement of the
effectiveness of the newest submarines.
Beginning in the 1960s many of operational and analytical activities continued to be centered in
SubDevRon 12 (formerly known as SubDevGru 2). DevRon 12 was the home of the Tactical Analysis
Group (TAG), played a major role in the "Big Daddy" exercise series, and its submarines were also
assigned many forward intelligence missions.
The TAG was set up to develop analytical techniques for analyzing
exercise results and use them to predict operational performance. Big
Daddy was an annual, SSN versus SSN ASW exercise which the submarine
force used in part to develop and validate the models developed by the
TAG. These models could then be used in war planning, in setting force
requirements and to assist in the design of new systems. Big Daddy and
TAG were key tools for the Navy to use in convincing both itself and the
national leadership of the viability of its ASW posture. The TAG also
developed into a formidable tool for justifying new submarine development to the civilian
leadership, particularly in the years the Office of the Secretary of Defense was infected with
enthusiasm for the quantitative methods first introduced by Robert McNamara in the early 1960s.
In this capacity, the TAG played a major role in the justification for the Sturgeon, the first SSN
class produced in large numbers.

DevRon 12 also played a major role in the introduction of new sensor technology. Part of its
charter was to test new equipment, but because it also had an operational role, these tests often
occurred in real world operations. Once the value of an experimental system was established in
this way, it tended to be retained for further use in the DevRon, rather than returned to its
manufacturer for further development. This low level melding of the technical and operational
communities provided an informal path for new technology like LOFAR and the towed array to be
inserted into the submarine force.