When the old warship Constellation returns to Baltimore's Inner Harbor today, its flags and pennants flying, it will be greeted by cannon, the roar of Navy jets and a huge sigh of relief.

"There were a lot of people who thought this would never happen," said Gail Shawe, chairwoman of the Constellation Foundation, who led the ship's rescue.

The 145-year-old sloop of war -- a veteran of the Civil War and anti-slavery patrols off West Africa -- has just completed a 30-month restoration that cost $7.3 million. It has survived rot, doubt and penny-pinching to return stronger, sounder and truer to its history than at any time in generations.

Nearly six years after Navy inspectors found it dangerously weakened by rot and neglect, Shawe said: "This ship is in great shape, and has a wonderful future ahead of her."

The Constellation will leave Pier 8 in Locust Point at 9 a.m. Lashed to the tug Vane Brothers, it will carry Gov. Parris N. Glendening, Mayor Kurt L. Schmoke, former Navy Secretary John H. Dalton, donors and board members.

It will head first for Fort McHenry. At 10 a.m. it will exchange cannon and flag salutes with the historic battery. Then it will be escorted upriver by a parade of 25 historic yachts, steam and sailing vessels and naval craft.

The ship will be greeted at 11 a.m. by a fireboat display in the Inner Harbor basin. The Maryland Army National Guard will fire a 19-gun salute from Rash Field at 11: 30, followed by a flyover by two Navy F-18 fighters. Formal ceremonies will begin at noon at Constellation Dock.

Visitors will find the 179-foot vessel considerably changed since it was towed away, trussed up and dismasted, on Nov. 17, 1996.

A sloop, not a frigate

Shipwrights have attacked persistent public confusion over the ship's history by restoring it as accurately as possible to its original appearance as a sloop of war, launched in 1854.

Guided by the ship's original plans, diaries, and evidence found on board, they removed many details added during the 1960s and 1970s in attempts to make the ship look more like its much older namesake -- the famed frigate Constellation, launched in Baltimore in 1797 and dismantled in 1853.

Frigates had guns on two decks, but a sloop of war did not. So the guns are gone from the Constellation's top deck, and solid bulwarks have replaced its open rails. Space at the base of the ship's bowsprit -- open on the old frigate -- has been enclosed to match the 1854 plans.

Shipyard workers also restored brass portholes to the berth deck -- original equipment that had been planked over.

Some observers may notice more subtle changes, including one of the most important: the Constellation no longer sags. The ship's 27-inch "hog" -- a dangerous, frown-shaped bend in its keel caused by gravity and rot -- was straightened in dry dock.

Rot replaced by new wood

Shipwrights also ripped out and replaced the top two decks, which were not original. Many rotted frames, or ribs, also were torn out and replaced by new wood. They tore off hull planks, too, from the top down to the first sound wood they encountered, about 10 feet above the keel.

In the project's most controversial departure from traditional techniques, shipwright G. Peter Boudreau replaced the thick oak planks with four layers of thin fir planks, laid down on alternating diagonals and glued together with modern epoxies.

The nontraditional fix isn't apparent to the observer, and it saved the foundation millions of dollars. The ship's hull is now watertight, and strong enough to bear the ship's weight. That relieved its weakened timbers, extended the hull's lifetime, and permitted the retention of 50 percent of the ship's original wood.

The ship has its original keel, many frames and bottom planks, rudder and officer's quarters. The lower decks -- the orlop and berth decks -- are little changed. The old wood is dark and gnarly, and easy to spot where it's exposed.

Chris Rowsom, the Constellation's new director, called Boudreau's repairs brilliant. "I'm told it's 30 percent stronger than originally built," he said. But don't expect the ship to head for sea.

"She was restored with the mission of being an Inner Harbor attraction, not with the idea that she would go to sea," Shawe said. The rudder doesn't work, and "her masts haven't been installed in such a way as to be able to take the strain of working sails."

Strain and surprise

There was plenty of strain during the repair. Navy approvals were delayed. Some amateur historians tried to revive the old debate over whether the old frigate was converted in 1854, or replaced by the present ship. "It's like being stuck in glue," Boudreau said of the stubborn controversy. "After a while, we didn't answer them any more."

Once work began, there were repeated surprises as wood proved weaker or sounder than expected. Flexibility and innovation became routine. Last year, the foundation was slapped with a lawsuit demanding wheelchair access to the ship. It was settled.

And always there was money, or the lack of it. At one point, the foundation laid off its entire office staff, save two. "We had to take whatever resources we had and put them on the ship," Shawe said. Even so, Boudreau was told to cut costs, and somehow trimmed $400,000 from his budget.

The Constellation Foundation had hoped to raise $9 million, but received less than $8 million. The city gave $3 million. The state provided $2.5 million. The rest -- less than $2.5 million -- came from the private sector.

In the end, the restoration cost $7.3 million.

Education and tourism

When today's speeches are done, the Constellation Foundation will turn the ship's title over to Baltimore City. Under an agreement with the city, the Living Classrooms Foundation will operate it as an educational resource and tourist attraction -- part of its National Historic Seaport.

The ship goes to the Living Classrooms Foundation today debt-free, with roughly $100,000 in cash, Shawe said. It's not the endowment she had hoped for, but "we saved the ship, and she's coming back with something more than $3.50 in the bank."

Living Classrooms plans to divert 25 cents from every admission ticket to a fund for the ship's future repairs.

Rowsom said visitors will see gradual additions to the rigging, equipment and furnishings over time, plus Civil War-era guns, demonstration sails and construction of the ship's longboats.

"Over the next few years, there's always going to be something new here," he said. "We don't want to let the momentum of the restoration stop."

The Constellation plans free tours from 2 p.m. until 7 p.m. today. The ship will then be open daily from 10 a.m. to 8 p.m. Admission is $6 for adults, with discounts for children and seniors.

The restored Constellation

Shipwrights restored the Constellation to its historic configuration as an 1854 sloop of war. About half the ship's original timber was preserved, including the keel, rudder and many ribs and hull planks below the waterline. But most of what can be seen from shore is new.

The spar deck

A. Added curved pin rails.

B. Added hammock rails, used for storage.

C. Reduced size of central hatch.

D. Built new working capstan, used to raise anchor.

E. Opened galley hatch.

The gun deck

F. Rebuilt riding bitts, heavy posts for anchor chains.

G. removed the stove, to be replaced by an authentic one.

H. Restored captain's cabin.

The lower decks

The lower decks were mostly untouched. The berth deck, shown at right, can be viewed except for the chaplain's rooms. The orlop deck, not shown is closed.

Constellation route

9 a.m. Ship departs Pier 8 at Locust Point lashed to the tug boat Vane Brothers.

9:45 to 10 a.m. Will arrive off east side of Fort McHenry for a gun and flag salute.

10:30 to 11 a.m. Will head back upriver to the Inner Habor basin.

11:30 a.m. There will be a gun salute and a flyover by Navy F-18s.

12 noon Formal ceremonies at the Constellation dock.

2 p.m. to 7 p.m. Free tours.