BARKING SANDS, KAUAI >> One of the Army’s new roles — at sea rather than on land — was on display Tuesday 55 nautical miles north of the Garden Isle during Rim of the Pacific exercises.

Two AH-64D Apache attack helicopters from Schofield Barracks launched eight “fire and forget” AGM-114L Hellfire missiles at the decommissioned Pearl Harbor frigate USS Crommelin.

The Hellfire has been used since 1985, and widely in Iraq and Afghanistan, but the model fired Tuesday is being refined for Army use with the goal of maximizing its approximately 5-mile range for enemy small-boat swarming attacks and other threats.

Chief Warrant Officer 3 Drew Coombs, one of the Apache pilots in the exercise, said that when he fired Hellfires in Afghanistan, he needed to keep a laser on the target while the missile was in its entire flight.

The Hellfires tested off Kauai use a laser return to provide inertial data to the missile’s radar.

“We squeeze the trigger and that’s all,” Coombs, 40, said. “We don’t have to track it inbound. It took a radar snapshot of what it’s going after and flies straight into it.”

In theory, anyway. Some of the fired missiles hit the approximately 450-foot Crommelin, and some apparently didn’t. Data from the test will be used by engineers for further improvements.

“This will open the field for different mission sets,” Coombs said before the test.

That field is being expanded for the Army to over-water littoral, or coastal, missions in the Pacific, where most populations live and most navies operate. Drawdowns after years in Iraq and Afghanistan and budget cuts have steered the Pentagon away from the type of costly land wars to which large numbers of soldiers were central.

The resurgence of Russia and rise of China, and frequent natural disasters in the Pacific, meanwhile, have emphasized the importance of maritime capabilities — even for the Army.

Adm. Harry B. Harris Jr., head of U.S. Pacific Command, said in May in Honolulu that future security needs will require the military services to “exert influence in nontraditional domains,” including the maritime environment.

That might not come naturally to land forces, but it’s something the Army has done before, Harris noted.

During the Civil War, Army coastal artillery was used to engage ships, he said. In the early 1900s the batteries at Fort Kamehameha on what is now Joint Base Pearl Harbor-Hickam were built for a maritime threat.

As time passed, improved maritime and air capabilities allowed the Army to divest itself of the coastal defense business. But Harris said that in the 21st century the Army should get back in the coastal defense game, and suggested that it’s “got to be able to sink ships, neutralize satellites (and) shoot down missiles.”

Schofield Barracks soldiers have been practicing landing Army helicopters on Navy ships in recent years. In November, 25th Combat Aviation Brigade troops practiced jumping into the surf from a low-flying Chinook helicopter.

Lt. Col. Aaron Martin, commander of Schofield’s 2nd Squadron, 6th Cavalry Regiment, and its 24 Apaches, said shooting Hellfires at ships “is just another capability that we bring.”

The wasplike two-seater attack helicopters arrived in Hawaii in April.

“Obviously, the Pacific region, our region of responsibility, is a maritime environment,” with deep-water threats the purview of the Navy, Martin said. But the Army has “that capability to move beyond the ground out there to the sea, to provide that depth of protection for the local national population on any of the islands of our partner nations.”

The more than 5-foot-long Hellfires used Tuesday aren’t big ship killers, but the “sink exercise,” or “sinkex,” involving the Crommelin was a rare opportunity to test the evolving Army helicopter missile technology.

“Actually, because we’ve been shooting so many missiles in Afghanistan and Iraq for the last two years, we’ve had no training missiles available,” Martin said. The missiles tested off Kauai were “going to be the only ones shot in testing in the last couple years.”

The Army was the third shooter of the day, following a Navy P-3 Orion reconnaissance plane and Navy SH-60 helicopters, he said.

“We really don’t have the capability to sink a ship this size,” Martin said. “That’s why we’re all participating in this today.”

Smoke billowed from the frigate with some of the Hellfire hits, which came in from a distance of several miles with the Apaches at about 1,000 feet, but the ship didn’t appear structurally damaged.

The helicopters looped around several times, lining up behind the Crommelin’s stern for the missile shots.

The Crommelin was the second retired ship targeted during RIMPAC. The Navy said that in addition to the United States, Australia, Canada, New Zealand and South Korea would be participating. The sinkex was also to include the first Harpoon missile launch from a littoral combat ship, a type of fast, shallow-draft coastal vessel being deployed by the United States to the South China Sea and Singapore.