But when Mr. Whitney, one of 202 midshipmen to graduate from the United States Merchant Marine Academy in Kings Point, N.Y., on Monday, stepped forward to receive his diploma, it just sort of happened. Call it irrational exuberance. But after six years of undergraduate school and 4,872 demerits, Mr. Whitney, 25, of Nashua, N.H., could hardly restrain himself.

With more reason than most to be overjoyed, the 6-foot-7 midshipman stepped onto the stage to accept his degree and hugged Vice Adm. Joseph D. Stewart, the academy's superintendent. Then he raised both arms in a victorious salute as his classmates roared their approval.

Elated and with his arms still upraised, he turned toward President Bush, who had just delivered the commencement address.

Mr. Bush, wearing a quizzical expression, responded by raising his arms as well and moved in for a hug. The midshipman — almost unwittingly — found himself squeezing the president in his powerful arms. When the president caught his breath, he shook Mr. Whitney's hand.

"I said, 'You're the man! Thank you very much,' " Mr. Whitney said in a telephone interview yesterday.

"The president thought the big bear hug was funny," said Dana M. Perino, a White House spokeswoman. "He appreciates the terrific enthusiasm of our nation's graduates, and he was honored to be the first president to address the Merchant Marine Academy. It was quite a thrill for everyone."

Mr. Whitney's sister, who works in an advertising office, had designed T-shirts for the 15 family members who attended the ceremony. Mr. Whitney's many difficulties in reaching graduation were emblazoned on the front of the shirt: 4,872 demerits ("painful"); four and a half years on academic restriction ("wounding"); two visits to the committee that weighs student expulsions ("agonizing"); two reprieves from the admiral ("necessary"); and six years of school with only an undergraduate degree to show for it ("humbling").

The back of the shirt, which bore a photograph of the midshipman and the American flag, celebrated his crowning achievement: "Passing all licensing exams, first try: Priceless."

Reached in New Hampshire, his grandmother, Alberta Whitney, said that some of the 4,400 people in the audience took pictures of the T-shirts, front and back.

"We were very happy to pose," she said. "We are so proud of Gabriel. He's a wonderful, wonderful boy."

The day after graduation, Mr. Whitney said he had no immediate plans but one long-term goal: "I plan to achieve greatness someday, though I'm not exactly sure yet how I'm going to do it."

For now, he is relaxing and basking in the attention that his widely publicized hug has garnered.

"I'm trying not to think farther than the next couple of days," he said, adding with a chuckle, "It's been kind of a long trip."