PEARL HARBOR — The three soldiers stood at attention in camouflage uniforms and desert combat boots for the change of command and then did what comes naturally for their unit: They donned yellow dive helmets and scuba tanks and jumped into the deep end of Richardson pool.

The 7th Engineer Dive Team changed command underwater yesterday in a ceremony that was as unusual as the unit itself.

Fourteen other divers stood at attention in the shallow end and marched, in scuba gear, to the 11-foot-deep section of the pool for the transfer of the unit's red guidon, or flag, from the departing commander to his incoming replacement.

Capt. Adrian Biggerstaff took over for Capt. Thomas Darrow. The dive team is part of the Army's 65th Engineer Battalion, whose commander, Lt. Col. Daniel Koprowski, also was part of the underwater change of command.

There are only about 100 divers in the Army, officials said. There are five detachments at Fort Eustis, Va., a training detachment in Florida and the team of about 25 divers based out of Fort Shafter Flats.

Biggerstaff, the unit's incoming commander, said that nine years ago he heard a rumor that the Army had divers.

"I didn't believe him. I had to check it out," Biggerstaff told those assembled yesterday for the command change. "... I found out the Army had divers and also, I found the Army had divers in Hawai'i. From that day, I had the dream to command that unit."

As the new commander, Biggerstaff had to keep up a dive team tradition: cross the length of the 25-meter pool underwater on one breath. And while wearing 80 pounds of gear.

The unit deployed for nearly 15 months to Operation Iraqi Freedom between 2006 and 2008, performing dive missions in Iraq, Kuwait, Bahrain and Qatar.

The divers performed "security swims" in ports and around bridges, demolition missions and searched underwater for fallen soldiers and equipment.

They will deploy again early next year as part of the Iraq mission — which is being renamed Operation New Dawn. The unit has a 27-foot boat and six Zodiac inflatable boats.

Last summer, the divers helped the U.S. Army Corps of Engineers with a breakwater project in Ketchikan, Alaska.

In late 2009, 13 members of the 7th Engineer Dive Team restored a coral reef off Kwajalein Atoll that was damaged when old ordnance was destroyed.

In January and February, the dive unit traveled to Cambodia to assist the Joint POW/MIA Accounting Command and dove on two sites, one in a river and another off the coast, to examine helicopter crash sites that may still have the remains of missing U.S. personnel.

In August and September, 7th Engineer divers will head to the Mediterranean island of Corsica and dive in about 120 feet of water as part of additional assistance to the Joint POW/MIA Accounting Command.

"The most important thing, the things that I take away with me are these (missions) we do for JPAC — helping to recover soldiers fallen from past wars," said Darrow, who's leaving the dive unit after 22 months in command.

Darrow, 29, of Cranston, R.I., won't be going far; he's been assigned to JPAC, which has its headquarters at Hickam Air Force Base.

The Army divers work for land-unit commanders "doing the rivers and muddy-water diving. Other services don't have that," Darrow said.

Darrow passed a unit trident to Biggerstaff, the new "Trident 6," or commander, and gave him a command coin. Actually, he threw it into the deep end of the pool.

"You can get that later," Darrow quipped. Biggerstaff grabbed it on his breath-holding trek across the bottom of the pool.