A popular rock 'n roll tune from the 1960s, "Here they come...from all over the world," seems an appropriate description of the arrivals of competitiors and spectators for the 27th annual Head of the Charles.

Regatta officials expect that more than 4000 competitors and between 200,000 and 250,000 spectators will come to see the Head of the Charles, one of the most popular rowing events in the world.

Nearly all area hotels are fully occupied by athletes or visitors who made reservations months in advance, according to local lodging managers.

"What hit us especially hard this week was the inaugural," said Harvard Motor House manager Catalino Rodriguez, refering to the installation of Neil L. Rudenstine as the 26th president of Harvard yesterday.

"Most of the people who came for the inaugural decided to stay for regatta--its been crazy around here," Rodriguez said.

Late yesterday, the atmosphere around Harvard Square grew more festive as more people arrived. "We came to party and see the races," said Cindy London, a college student from New York City.

The annual event has increasingly attracted more and more foreign competitiors, said Mike Donnellan, a regatta official. "This is particularly true with respect to Eastern Bloc countries," Donnellan added.

"We like coming here," said Yuriy Pimenov, the captain of the Dinamo rowing club from Moscow. "This is our second year in this event and we always look forward to the competition," Pimenov added.

"Boston and Cambridge reminds me of Edinburgh," said Ben R. M. Helm, who will enter the lightweight singles competition representing the Thames Tradesman Rowing Club from London.

"I like the bends in the river and its an interesting course," Helm said. "That's why I like coming here." He added that this is his third trip to the regatta.

Arriving overland from the Midwest is an eight-member women's team from the University of Wisconsin.

"We love coming here because its beautiful and the regatta gives us a chance to row against teams from all over the world," said Amy M. Nelson, a junior at Winsconsin.

"The competition is very good in the regatta--it's a special event," said Kathy V. Ponti, another member of the Winsconsin team.

"Aside from the competition, the regatta is a major social event," said Janice Fornaciari, catering manager at the Charles Hotel in Cambridge. "We have regatta-related parties and social functions lined up all weekend," Fornaciari said.

"It should be a good weekend for all," she said.