The USS Fairfax County, a 562-foot tank-landing ship capable of circling the globe without refueling, sailed home to its namesake last weekend.

The ship, one of 20 tank-landing ships in the U.S. Navy fleet, all named after counties, is designed to carry Marines and their equipment, especially tanks, trucks and other heavy equipment that cannot be readily landed by helicopters. The only other tank-landing ship named after a Washington area county is the USS Frederick County.

In January 1983, the Fairfax County was one of two tank-landing ships deployed to transport about 400 Marines each to Beirut as part of the multinational peacekeeping force there. It was fired upon several times during that mission, said Lt. Don Streetman, but no one was injured and the ship was not damaged. The Fairfax County did not return fire, Streetman said.

Last Friday, the Fairfax County left its home base in Norfolk's Little Creek Naval Amphibious Base for the Quantico Marine base. There, the ship picked up about 50 passengers Saturday morning, including elected officials such as county Supervisor James M. Scott (D-Providence), members of the media and other guests, for a voyage up the Potomac to Alexandria.

The ship docked Saturday afternoon at the Franklin Street pier. Several thousand people visited the ship on Sunday, ship's officers said.

Navigating the often-shallow Potomac can be treacherous. The massive ship, one of the biggest that can travel the Potomac, displaces 8,600 tons and draws about 17 feet of water, which means that it must be in water more than 17 feet deep. At several points on the trip, the deepest water was only 21 feet. To preclude disaster, the ship employed an experienced river pilot, Robert L. Face, as an adviser to Capt. Andrew J. Fosina. Face is a familiar figure on the Fairfax County. This was his seventh time leading the ship on the Potomac. Face has been licensed to pilot on the river for 42 years. As he put it, "If I were a senator, I'd be starting my seventh term."

Punctuating his conversation with shouts of "Right 10 degrees rudder" and "Steady on course, zero-nine-zero," Face said he likes guiding ships on the Potomac because "it's a very interesting river; there's a whole lot of piloting involved. If we were on an airplane, we'd call it 'flying by the seat of your pants.' I use lots of landmarks -- buildings, rock formations, so I know when to turn and how far. It's a challenge to do this large a ship. But the people on board are superb -- talented and friendly."

As the ship neared Mount Vernon, the mood became almost reverent. The crew prepared for a brief but moving ceremony as it passed the mansion once owned by George Washington. The ship stopped, and an eight-member honor guard came forward. Upon completing a brief drill, the honor guard faced the mansion and stood at attention, rifles held high. The rest of the crew saluted at the rail to a recording of "Taps," followed by the national anthem. Capt. Fosina said that all naval ships that pass Mount Vernon are required by naval regulations to render honors to our country's first commander-in-chief.

The ship then continued toward the Woodrow Wilson Bridge, which was raised to allow it to pass. Traffic backed up on both sides as far as the eye could see, but motorists appeared not to be upset. Many got out of their cars and waved.

All that remained was to dock the ship and hold an "adoption ceremony," whereby the Northern Virginia Council Navy League made the ship one of its own. Charles Beatley, mayor of Alexandria, and John F. Herrity, chairman of the Fairfax County Board of Supervisors, were among the featured speakers at the shipboard ceremony, with music provided by the Fairfax High School band.

The ship, which was commissioned in October 1971, resembles a floating apartment building. It has 11 floors inside and is equipped with air conditioning and closed-circuit television. It has a barber shop, a convenience store and even dry-cleaning facilities for the ship's 12 officers and 233 enlisted men (there are no women assigned to the ship)