Aboard the USS Missouri - For the last decade, submarines have been gathering intelligence and patrolling the world's oceans to make sure the Navy's fleet could get where it needed to go, while the Army and Marines fought ground wars in Iraq and Afghanistan.

But military strategists believe the next battleground will be the sea. In the last year, the submarine force has ordered its sub commanders to aggressively ready their boats.

The strategic focus is shifting to the Asia-Pacific region. China, Russia, India, the United Kingdom and France have nuclear-powered submarines. Pakistan, Brazil and Australia want them. Iran has threatened repeatedly to shut down the Strait of Hormuz. And more nations and groups will have access to long-range weapons because the technology is getting cheaper.

In a world where more countries are building submarines and trying to keep U.S. forces out of the waters near their borders, the submarine force's new strategy document, the "Design for Undersea Warfare," asserts that the old approach won't work.

Instead of watching the enemy, submarine crews are preparing to be a disruptive force.

They're practicing new ways they can cause trouble for an adversary, short of firing torpedoes. At sea, they're honing their skills to sink enemy warships.

They're fixing broken machinery themselves, instead of returning to port. Commanding officers are expected to make decisions without checking in with their superiors back home. All of the back-and-forth chatter that has been encouraged in the past compromises stealth.

"We're at a pivot point in our military strategy," said Rear Adm. Richard P. Breckenridge, commander of Submarine Group Two, based in Groton.

Nowhere are these changes more evident than aboard the USS Missouri (SSN 780). The Groton-based crew was in the Bahamas earlier this month, firing exercise torpedoes and practicing how to evade a "torpedo" launched by a simulated hostile submarine.

"We're returning to our roots," Lt. Cmdr. David Rogers, the executive officer on the Missouri, said. "We're going to sea and we're practicing for war."

The strategy isn't meant to start trouble - it's supposed to prevent it, Rogers said.

"Should war come to find us, we would be ready," he said. "And communicating that, that's in the interest of preventing war in the first place."

'We train the way we fight'

"Attention in control. Maintain course. This is a wartime scenario," the officer of the deck announced to the Missouri's control room March 9.

"Sonar ready." "Weapons ready." "Shoot Tube 1."

Water shot through the torpedo tube. The air pushing the water out jolted the submarine.

The men in the control room rapidly called out commands and information as they tracked the simulated torpedo and the simulated enemy sub.

"Active homing, terminal homing," shouted the chief manning the fire control station.

"Torpedo evasion!" came the response. The pilots drove the submarine down 400 feet, ending the exercise.

Chief Brian Paugh, whose finger was on the trigger, said firing a real torpedo sounds and feels the same as shooting water through the tube.

"We train the way we fight," he said. "It's how we make ourselves better."

Last summer, Vice Adm. John M. Richardson, the commander of the submarine force, released the "Design for Undersea Warfare," which says submarine crews must be ready to fight behind enemy lines for long periods of time, without support. Richardson told submarine commanding officers he would give them the freedom to do what they felt necessary to get their boats ready to deploy.

Just as these changes are taking hold, the Missouri is finishing the testing phase that all new submarines must go through and preparing for its first full deployment next year. The seventh member of the Virginia class, the sub was commissioned in 2010.

The entire class was built with flexibility and versatility in mind because the submarines will need to be as effective in 30 years as they are now. And as the number of attack submarines in the fleet drops from 53 today to 39 in 2030, each one will be expected to do more. The stated number of attack submarines required for the missions is 48.

The torpedo room on the Missouri was designed to be reconfigured easily to fit the weapons of the future, and Navy SEALs. Cmdr. Timothy Rexrode, the commanding officer, said the Missouri hasn't worked with the special forces yet, but it could.

Unlike older submarines, the Missouri doesn't require major surgery - cutting the decks and installing new mounts- to upgrade the combat suite. It's plug-and-play technology.

"Being the newest with the newest technology, Missouri will be one of the most covert," Rexrode said.

Breckenridge said the Missouri can continue to "morph itself and be a very effective platform to have a disruptive effect." Submarines can confuse the systems that adversaries rely on, from the cyber realm to the sensors that attempt to track military ships and aircraft.

The submarine, Breckenridge said, has "come to the table at the right time, given the challenges we face for the future."

Solving problems

Rexrode is the type of commanding officer the submarine force says it is looking for.

He set a grueling schedule to get the Missouri through its initial tests quickly so it could get to sea. And he stuck to it.

"Under Cmdr. Rexrode, Missouri really accomplished things very few other crews have been able to accomplish and I've never seen accomplished," said Rogers, the executive officer.

Missouri completed its sea trials in December, more than a month ahead of schedule, saving the Navy about $1 million. It was then available to support major fleet exercises, which freed up other submarines for other jobs.

Just this month the sub completed its latest certifications at the Atlantic Undersea Test and Evaluation Center in the Bahamas. Overseen by the Naval Undersea Warfare Center in Newport, R.I., AUTEC is considered a unique, natural deepwater range ideal for underwater testing.

Rexrode fought through the bureaucratic hurdles that tend to slow down a submarine's development, Rogers said, and he molded a group of relatively young and inexperienced junior leaders and sailors into a crew that could learn quickly and perform.

The adjective "aggressive" comes up often in conversations about Rexrode.

"He is a very aggressive man, and he will tell you that himself," said Senior Chief Ronald Clark, chief of the boat. "He's a very intense man and very smart. And for me as a submariner, that's exactly what I want in a commanding officer. There is no doubt in that man when he says something and that's absolutely what you need."

When the microwave oven on board broke this month, the sailors initially said there was nothing they could do. They didn't know how to repair microwaves.

Rexrode's response was "Fix it."

"It's a very small example, but it's a big shift from the way we used to think in the past 10, 15 years," Clark said. "If something used to break in the past we would immediately think, 'Do we need to go home and get this fixed?' Now the first thought is, 'How can we fix it now and do the job we need to do?'"

The microwave got fixed.

"If we have a mission to do, there's a reason for us to be where we're at," Clark added. "If we have to leave, it means someone else has to take our spot and that ripples through the submarine force and changes everything."

Rexrode said submarines are "designed to be at sea, doing business in the interest of the American people" and he was determined to get the Missouri there as quickly as possible.

"I think every submarine commander recognizes that's his responsibility," he said. "We, as a submarine force, through the Design (the strategy document), are all thinking that way."

Being a submarine commanding officer is like being a coach, said Rexrode, who will turn over command on April 20 to Cmdr. Michael Luckett.

"I tell my people three things," Rexrode said. "I tell them on day one, 'Try your best to do your job right. Understand when you can't do your job right and tell someone about it. And treat each other right.'"

Rexrode said he is in charge of a group of men of "impeccable integrity," who are willing to face reality and work with their shipmates "to accomplish a mission under difficult and demanding circumstances."

j.mcdermott@theday.com

Editor's Note

Jennifer McDermott spent four days at sea on the USS Missouri, one of the newest and most advanced Virginia-class submarines in the fleet.