At night, the silent flashes of a heat lightning storm look menacing when you're 70 feet above the deck of a schooner adrift on the Chesapeake Bay.

Ask Glenn Woodson and Mary Lou Veillare of T.C. Williams High School, cadets in a sail training program on the three-masted topsail schooner Alexandria. Overcoming fears about climbing the schooner's rigging is one of the first obstacles the high school sailors have to overcome.

"It's really scary looking down," said Veillare.

"If you think about being up there and how high you are and what a great fall it would be, you get scared," Woodson added.

"You have no lights, so you go by what you feel and remember from what you do in daylight," added another cadet, Thomas Longstreet.

Since the sail training program was begun by the Alexandria Seaport Foundation last September, about 35 students from Alexandria's schools have learned everything from nautical jargon to handling the maze of lines and rigging that control the 7,000 square feet of sail on the 125-foot vessel.

The cadets also learn about themselves, according to Longstreet, a senior at T.C. Williams. At 16, the blond student, his nose peeling from sunburn, speaks with the authority and seriousness of an old sea captain. Longstreet, who has worked on the Alexandria for over a year, is one of seven cadets now manning the schooner, docked at Waterfront Park at the foot of King Street.

"When you go out on the yards, you learn about yourself -- what you can take and what you can't take," Longstreet said.

Fortunately, life on the Alexandria is not one of constant nautical derring-do.

In fact, Capt. Bert Rogers and first mate Terry Linehan emphasize the importance of teamwork, responsibility and learning to do something the right way. The training crew also includes engineer Dave Robinson, and two deck hands, Rogers' wife Susan and Kevin Hengerle.

The crew of the Alexandria learned the lessons of seamanship by sailing and working on ships and boats around the world -- from crabbing vessels in the Bering Sea near the North Pole to outrigger sailing canoes in the South Pacific.

Rogers said that accepting the challenges of sailing helps the cadets mature. "Growing up is difficult. There's no way to polish an apple aboard ship," said Rogers.

During night sailing, the cadets take turns doing the three 4-hour watches from the bow of the ship. During voyages the cadets also steer the schooner, Rogers said.

And then there's life in port.

"Part of the life of a sailor is also doing maintenance work," Rogers said, varnishing the exposed wood on the deck and repairing ratlines, the tarred rope ladders that run to the mastheads.

It's the willingness to work on the Alexandria even when she's not sailing that separates the serious students from those with a passing interest, said first mate Linehan. "Since we don't sail that much, it's a little disheartening to them and they'll leave. They'll weed themselves out by virtue of the hard work," said Linehan.

The converse is also true. "If a cadet is really interested, we're ready to take him to any level of sail training he wants to achieve," Linehan added.

Longstreet, Veillare, and Woodson along with Cary Lerner, 16, and Claude Walsh, 17, make up the corps of the most dedicated cadets, according to captain Rogers. On Monday and Tuesday afternoons during the summer, they will come to the Alexandria to help out or just to be on the ship.

Walsh said the sail training will be good experience if he decides to join the Navy, but that is a secondary consideration. "Basically it's just fun. It's work, but it's fun," Walsh said.

Longstreet and Woodson said that they will seek entry into the Coast Guard when they graduate from high school. Like the navies of many countries, the U.S. Coast Guard uses a tall ship, in this case the USS Eagle, to train cadets.

The nonprofit Alexandria Seaport Foundation decided that the classes, open to Alexandria teen-agers between 13 and 18, would be an ideal way to promote seafaring among Alexandria's youth. The foundation, formed by local business leaders in 1982, also sponsors lectures on Alexandria's maritime history and plans to establish a center to promote boatbuilding and other nautical crafts.

To finance the ship's voyages and upkeep, the foundation rents out the Alexandria to businesses and organizations for dockside receptions. Most of the foundation's $200,000 annual budget goes toward crew salaries and schooner maintenance. Money for the budget comes from private donations and fund-raising operations, said the group's director, Mary Jane Malone. The city of Alexandria has also contributed $50,000 annually for the ship's upkeep and restoration over the last two years.

Malone is enthusiastic about the student program. "There isn't anything quite so romantic as putting kids on a ship like this. It would be static if you're not doing anything with it. It's kind of a laboratory for the kids," Malone said.