by MC 2C Brian G. Reynolds

For Commander, Submarine Group 7 (CSG 7), maintaining peace and security throughout the undersea domain of the U.S. 5th and 7th Fleet area of operations (AOO) is like playing a game of chess on a liquid chess board that blankets more than 50 million square miles.

Headquartered at Fleet Activities Yokosuka, Japan, CSG-7 coordinates all submarine operations from the Western Pacific Ocean to the Red Sea. Also as Commander, Task Force (CTF) 54 and CTF 74, the command boasts more than a half century of undersea dominance.

Maintaining this strategic undersea advantage is no simple task. It entails a copious amount of moving parts; although the submarines are the center of battle, it’s not all just about the submarines.

The Guam-based submarine tenders, oceanographic survey vessels, and all of the Navy’s towed-array surveillance ships operating in the Western Pacific; all fall under the tactical control of CTF 74.


Submarine tender USS Frank Cable (AS 40) is moored in Sepangar Bay for a routine port visit. 

The Tenders

Lowering a Tomahawk cruise missile onto the USS Oklahoma City (SSN 723).

The job of keeping U.S. submarines supplied and operating forward takes an ample amount of work from two of the U.S. Navy’s most flexible vessels—the submarine tenders.

The Navy’s two submarine tenders, USS Emory S. Land (AS 39) and USS Frank Cable (AS 40), play a vital role in keeping CSG 7’s submarines operating forward. The two tenders furnish maintenance and logistical support for nuclear-powered attack, ballistic-missile, and guided-missile submarines.

Submarines are small vessels compared to other U.S. Navy ships. They do not have the ability to carry large amounts of supplies and weapons. This is where submarine tenders come into play.

“The tenders are a floating maintenance activity,” explains Lt. Cmdr. Patrick E. Tembreull, deputy chief of staff for materials of CSG 7. “They have similar roles to an Intermediate Maintenance Facility, but are unique that they are mobile and self-sufficient. They are normally assigned as the lead maintenance activity for Guam-based submarine availabilities.”

Submarine tenders also carry an extensive supply of replenishment and repair parts. These supplies can be rapidly shipped to anywhere they are needed around the globe.

One of the aspects that makes submarine tenders so much of an asset to CSG 7 is their inherent flexibility. They provide fly-away teams who can deploy from tenders to anywhere in the U.S. 7th Fleet AOO on short notice. These teams have been called upon to repair emergent material conditions in virtually every port that CSG 7’s submarines visit. They are also equipped to tend submarines in a wide variety of environments.

“The ships also perform repairs in remote locations when they tend submarines,” says Tembreull. “They can tend submarines at pier or at anchor and have a range of mooring options to fit different environmental conditions. Tenders have even tended [guided-missile destroyers] in the past.”

Similar to ocean surveillance ships, MSC personnel play a pivotal role in ships’ operations. Integrated in 2010, MSC mariners are responsible for handling the tenders’ deck operations, navigation, and food services. However, U.S. Navy Sailors maintain the ships’ support structures and repair missions.

Tenders are essential and extremely versatile assets that provide and maintain CSG 7’s vessels to be mission ready around the clock and throughout the year.

Ocean Surveillance Ships

USNS Able (T-AGOS 20)

Submarines operate under a cloak of silence. In the dark abyss of the deep, it is often more crucial to hear the opponent than to lay eyes on them. This concept is why anti-submarine warfare (ASW) is a strategic focus for CTF 74.

ASW plays a colossal role in what CTF 74 does on a daily basis, and ocean surveillance ships play into that role adeptly. In fact, ASW is their sole purpose. These ships deploy a Surveillance Towed-Array Sensor System (SURTASS) that provides mobile detection, tracking, and reporting of submarine contacts at a long range. In short, SURTASS ships act as CTF 74’s ears in the deep.

Roland Ailenbuade was a Sonar Technician (Surface) 1st Class aboard the ocean surveillance ship USNS Able (T-AGOS 20). He describes SURTASS as “an array attached to a cable. The cable is 4,900 feet long and there are two of them, port and starboard. We deploy [the array] which is made up of hydrophones that pick up sound in the water.” Ailenbuade is now a theater ASW specialist at CSG 7.

The information that is gathered by the array is then sent back to the ship via the cable. Equipment on the ship analyzes the data. It is then the job of sonar technicians to determine what the data that the array picked up actually entail.

“We train to differentiate what a submarine looks like, what surface ships look like, even what whales look like,” Ailenbuade says. “Anything in the water, we train to tell which is which.”

It is the collected data that are important to CSG 7, whose leadership uses it to make critical decisions on where to place its submarines and other assets. CSG 7 also uses the information to protect high-value units such as aircraft carriers and amphibious assault ships.

As Ailenbuade puts it, “[CSG 7] thinks big picture SURTASS is a strictly ASW platform, and it’s a big integral part of what we do here.”
Ocean surveillance ships are manned primarily by Military Sealift Command (MSC) mariners, but also embark U.S. Navy Sailors.
These vessels are responsible for bringing decision-making data to CSG 7 and are crucial to the overall mission of the command.

Oceanographic Survey Vessels

USNS Pathfinder (T-AGS 60)

The Chinese military strategist and philosopher Sun Tzu once taught, “Know yourself; know your enemy. Your victory will never be endangered. Know the ground. Know the weather. Your victory will be total.”

MSC’s special mission program boasts six Pathfinder-class oceanographic survey ships. These ships are equipped with numerous hull-mounted multi-beam echo sounders and towed side-scan sonar systems that allow precise mapping of the ocean floor. Each ship can also carry up to two hydrographic survey launches, which carry a similar sensor suite. In addition to their bottom-mapping capabilities, survey ships carry a wide variety of oceanographic sensors that they use to measure oceanographic conditions.

According to CSG 7’s Meteorological and Oceanographic Officer Lt. Cmdr. Jonathan Savage, “Understanding the environment better than one’s opponent is a tremendous advantage. the U.S. Navy is able to exploit that advantage thanks in large part to the work these survey ships do every day.”

Oceanographic survey ships are manned by a crew of 24 civilian personnel. For each survey mission, a team will embark consisting of up to 27 scientists, including civilians, from the Naval Oceanographic Office (NAVO) at Stennis Space Center, Miss.. While the ship’s crew expertly navigates along a precise track, the NAVO scientists collect precise bathymetric and oceanographic information.

As with any military operation, an intrinsic knowledge of the environment is essential to success. The bathymetric, hydrographic, acoustic, and oceanographic surveys that Pathfinder-class ships perform enable warfighters to exploit the tactical advantage created through understanding of the undersea environment. Oceanographic survey vessels operating in this area play an imperative part in how CSG 7 applies Sun Tzu’s two-and-a-half-millennium-old philosophy.

So in conclusion, when looking at the Asia/Pacific nautical chessboard on a global scale, it entails having all of the chess pieces in strategic positions. While CSG 7’s submarines are at the tip of the spear of operations in the U.S. 7th Fleet AOO, their success relies on the myriad of moving parts behind the scenes. Ocean surveillance ships, oceanographic survey vessels, and submarine tenders maintain CSG 7’s theater ASW dominance.