William Pinkney is the first black American to sail alone around the world, saying it was the thousands of schoolchildren around the country who tracked his every move that kept him going.

Pinkney, 57, completed the 27,000-mile voyage Tuesday when he docked his 47-foot cutter Commitment at the Charlestown Navy Yard, where the journey began Aug. 5, 1990.As he stepped on the dock just before noon to the cheers of hundreds of youngsters, Pinkney pushed his hat back on his head, took his wife, Ina, in his arms and said, "How you doing?"

The Chicago native said he made the trip to make people aware of the contributions of black Americans to the maritime history of the United States, and to inspire young people to set goals, make commitments and persevere under adverse conditions.

"I was able to touch positively the lives of other human beings, and that's a gift few people get in life," Pinkney said.

Thousands of students in Boston and Chicago and in other cities kept a daily log of Pinkney's progress thanks to the Argos satellite tracking system and a program coordinated by the Boston Voyages in Learning, which uses the marine environment as the focus of classroom learning.

The pupils also communicated with him regularly by radio during the trip, which took him down the coast of South America, across the southern Atlantic Ocean to Capetown, South Africa, through the southern ocean to Hobart, Tasmania, across the southern Pacific, around Cape Horn and up the coast of South America.

When asked what kept him going over the nearly two-year voyage, Pinkney gestured toward the surrounding throng of youngsters and said it was "because of them."

Pinkney, who is the first black to make such a voyage, did not appear tired as he ended his adventure, and said he would gladly do it again.