The city of Alexandria and its local American Red Cross chapter may become international ambassadors of good will this June if the tall ships of both Argentina and Canada come to city docks for the Second Annual Red Cross Waterfront Festival.

Canada already has agreed to send its 160-foot Nova Scotian gaff-rigged schooner Blue Nose II to the festival, and Canadian officials say they have no objection to being berthed beside an Argentine vessel.

Argentina has been invited to send its Libertad, a giant 345-foot square-rigged frigate and navy training vessel, but has yet to respond to the invitation. Said an Argentine Embassy official this week: "We might hear tomorrow, or it might be two or three months."

Canada, the largest of the self-governing nations in the British Commonwealth, supported Britain in last spring's war in the Falkland Islands--a war, incidentally, that Argentina insists is not over.

Alexandria's Red Cross chapter did not send invitations to Argentina and Canada because it wished to play an international peacemaking role, however.

"We were looking for large, handsome vessels. We didn't consider the Argentine-English connection. I don't even remember who suggested the Libertad, but she certainly is beautiful," said Sam Ellsworth, who is helping to organize the festival.

"However, after asking the Blue Nose, we did check with Halifax Nova Scotia to make sure it would not be uncomfortable for them if we invited the Libertad. We didn't want to be insensitive," Ellsworth said. "They said 'No problem.' "

Alexandria plans to make this year's festival, to be held June 4th and 5th, even larger than last year's harborfest, when the 137-foot Pride of Baltimore clipper ship was the center attraction.

Several other sailing ships have been invited, including the 300-foot Mexican tall ship Cuauehetomoc, according to Rob Whittle, who is in charge of publicity for the volunteer Red Cross event.

So far, only three ships have officially accepted: the Blue Nose, the 80-year-old skipjack Norfolk and the diminutive sloop Departure, built about 1910. At 14 feet 10 inches, the Departure is the world's smallest Maine Friendship sloop.

The Blue Nose II is a 1961 replica of the famous Canadian Grand Banks fishing boat that dominated international fishermen's races in the 1920s and '30s. Both vessels were built in the same Lunenburg, Nova Scotia, boatyard and by some of the same craftsmen.

If all the ships invited accept, the city could have a dock problem. It has only limited docking space at the Torpedo Factory and the old Ford Factory at the foot of Franklin Street. At least one ship already has declined because of other sailing commitments: the Belle Espoir from France.

In addition to ships in the water, the two-day festival will feature a wooden boat-building school, a demonstration involving the restoration of an old 32-foot wooden sloop, plus a "haunted ship," hot-air balloon rides, concerts, restaurant tents, a regatta, a fishing derby, an art show, a festival ball and the blessing of the fleet.

Last year's blessing of more than 50 pleasure craft in the Potomac followed a parade through Old Town headed by local clergymen and the Potomac River Jazz Band.

Construction equipment has blocked access to part of the Old Town waterfront this fall and winter as the World War I Torpedo Factory is being converted into office and commercial space and a new Art Deco home for the Torpedo Factory Art Association. The exterior construction work is expected to be completed this spring.