A Washington, D.C. attorney who once coached the rowing team at Howard University and was a backup on the 1956 Olympic rowing squad died yesterday after he collapsed and tumbled from his boat at the start of the Head of the Ohio rowing competition.

Stuart C. Law, 79, was pronounced dead at Allegheny General Hospital. The cause of death was coronary artery disease, according to the Allegheny County medical examiner's office.

"He'd been rowing way too long to simply tip over," said his son, Chuck Law, a Greensburg anesthesiologist who was waiting by a starting line for his father to cross with the other boats.

Mr. Law collapsed just as his event was set to start around 9 a.m. yesterday on the Allegheny River. After Mr. Law tumbled from his one-man scull boat, a race volunteer dove into the water and kept him afloat until a rescue crew arrived.

In 1989, Mr. Law, representing the Potomac Boat Club, won the Grand Masters Men's Single Scull competition national title.

"He took competition very seriously," said Chuck Law. "He had been fading a little bit and was concerned about his times."

Several years ago -- his son did not recall precisely when -- Mr. Law underwent heart-bypass surgery.

"My dad outlived his surgeon," Chuck Law said.

Richard A. Linn, district chief with the city's EMS, said it's unclear what happened yesterday morning.

"Apparently he was rowing just below the 40^th Street Bridge and just rolled off the boat. Another scull went over to help him up," he said.

Witnesses saw Mr. Law tumble from his boat and Suzetta Large, a race volunteer who was nearby, maneuvered over to his boat and dove into the water to rescue him. She pulled him to the surface and held him in the water with the help of her niece, Danielle Feley, until two men in a Three Rivers Rowing rescue boat pulled him onto their craft. One began performing cardiopulmonary resuscitation.

A Pittsburgh River Rescue unit quickly arrived at the scene and the crew there took him aboard and raced to the hospital while applying advanced life support, Mr. Linn said.

"Everything seemed to be in slow motion," Ms. Large said. "I just kept hoping that he would suddenly start breathing."

Ms. Large was volunteering to help monitor participants at the starting line.

"Little did I know there would be some sadness involved today," she said.

The race, being held just off Washington's Landing, halted briefly during the rescue.

In 1983, Mr. Law represented a fuel company that seized the Sequoia, the former presidential yacht often used by President Nixon, after its new owners failed to pay for $1,345 gallons of diesel fuel.

While the Sequoia case garnered him small attention, it was Mr. Law's attachment to scull racing -- a rowing competition in which a competitor sits in a slender, pointed craft and rows facing backward -- that remained his area of prominence.

He was a regular entrant in the Head of the Potomac scull races, in which he used his own innovation: attaching a rearview mirror to a headband to perfect his steering. His son said he also tested rowing machines for one manufacturer and was a regular contestant in the annual Marine Corps Marathon.

In a 1987 interview with The Washington Post, Mr. Law conceded that sculling was a grueling undertaking.

"But, you say to yourself 'nobody ever, ever quits,' " he added.

Yesterday, searching for records to arrange his father's affairs, Chuck Law said he came across an e-mail from a former student Stuart Law had coached. It was about a mutual friend and fellow rower who had died suddenly.

"This woman he used to coach wrote him in July and said 'Coach, row as much as you can as that will increase your chances that when your number comes up, you'll be rowing and you can go straight to heaven from there.' "