Maritime archaeologists and the Coast Guard announced the discovery Tuesday of what remains of the celebrated Coast Guard cutter McCulloch, which sank 100 years ago off the Central California coast.

The McCulloch was a famous ship in its day. It fired one of the first shots in the battle of Manila Bay in 1898 during the Spanish-American War, and then served on rescue and patrol duties out of San Francisco Bay for 20 years, including service in Alaska and the Bering Sea.

Identifying the wreckage of the ship “is a great day for the Coast Guard,” said Rear Adm. Todd Sokalzuk, commander of the Coast Guard’s 11th district in Alameda. The story of the McCulloch and its crew over the years “is an important part of our heritage and legacy,” he said.

The ship — 219 feet long and steam-powered — was the largest revenue cutter of its time, and also one of the fastest. But it sank in 35 minutes on the morning of June 13, 1917, after a collision in fog with the passenger liner Governor off Point Conception near Santa Barbara.

Formal identification of the ship’s wreckage was announced at a news conference at the San Francisco Maritime National Historical Park. The tale of the ship’s career and its abrupt end was part history lesson and part underwater detective story.

The McCulloch was built in Philadelphia in 1896 for the Revenue Cutter Service, forerunner of the modern Coast Guard. The ship was assigned to service in the Pacific, but instead of sailing the usual route around the tip of South America, it was sent through the Suez Canal and the Indian Ocean to its new station in San Francisco. The Panama Canal had not been built yet.

When the McCulloch reached Singapore, it was clear that war between the United States and Spain was in the air. The McCulloch was attached to the Navy’s Asiatic Squadron under Commodore George Dewey.

When war broke, Dewey’s fleet sailed for the Philippines, then under Spanish control, where it surprised and sank a Spanish squadron at Manila Bay. The American victory there helped establish the U.S. as a Pacific power.

Though the McCulloch was a revenue cutter — essentially a patrol ship — it carried guns and fired the first shots at Manila Bay. The McCulloch’s chief engineer, Frank Randall, was the only American fatality in the battle.

Later, the ship sailed into San Francisco, which became its home port. It was assigned to rescue missions, including responding to a major shipwreck off Bolinas, and to patrol duty in remote sections of Alaska and the Bering Sea.

When it was not on patrol, the McCulloch was a familiar sight in the bay. Its usual base was riding at anchor just off Sausalito, ready to put to sea on short notice.

In June 1917, the cutter was heading back to San Francisco from Los Angeles Harbor when it was sunk in 300 feet of water.

The wreckage lay undiscovered on the sea bottom until modern sonar detected a mysterious shipwreck 4 miles off Point Conception.

Not long afterward, marine archaeologists from the National Oceanic and Atmospheric Administration and the Coast Guard mounted an expedition to dive on the wreck. Robert Schwemmer, NOAA’s West Coast maritime heritage coordinator, described how scientists used a small remotely operated vehicle to explore the wreckage.

Though only a skeleton of the ship remained, Schwemmer used what he called “clues” — part of the ship’s unique torpedo tube, one of the ship’s guns and the steering wheel — to identify the wreck as the long-lost McCulloch

They also tracked down the grave of John Johansson, a McCulloch crew member who was injured in the collision and taken off the ship. He died in a hospital a few days after the accident and was buried with honors at a cemetery in San Pedro, at the edge of Los Angeles harbor.

There are no plans to raise the ship.

Carl Nolte is a San Francisco Chronicle staff writer. Email: cnolte@sfchronicle.com Twitter: @carlnoltesf