OYSTER BAY, N.Y. – A yacht that capsized with 27 friends and family aboard on an outing to watch Independence Day fireworks was severely overcrowded and doomed to tip over, safety experts said Thursday as the skipper blamed the tragedy on a wave that came out of the dark.

Three children died after becoming trapped Wednesday night in the cabin of the 34-foot vessel off Oyster Bay, on the north shore of Long Island.

Sal Aureliano, who was at the helm of the Candi I, told TV’s News12 Long Island that he saw two lightning bolts and then a wave suddenly hit.

“It turned the boat around,” he said, his voice cracking. “It just turned the boat. I didn’t see it. It was dark. I didn’t see it.”

Aureliano’s nephew David Aureliano, 12, and two girls, 11-year-old Harley Treanor and 8-year-old Victoria Gaines, died. The 24 other passengers, adults and children, were rescued from the water, mostly by fellow boaters, and were not seriously hurt.

“The next thing I know, we’re turning, and we just kept turning, and everybody was in the water. It was chaos,” Aureliano said.

The cause of the accident was under investigation, but it could have been the weather, overcrowding, the wake from another vessel or a combination of factors, Nassau County Detective Lt. John Azzata said. The area was crowded with boaters watching the fireworks, he said.

The Silverton yacht, built in 1984 but bought recently, was under 60 feet of water Thursday, and officials worked to raise it.

The yacht company filed for bankruptcy in April, and no one was available to say what the maximum number aboard should be.

Phil Cusumano, a Boston-based safety instructor and yacht captain with 35 years of experience, said there is no question the boat was badly overloaded. He said he would limit a vessel of that size to six adults. Other boating sites suggested a maximum of 15 passengers.

“Twenty-seven is just crazy,” Cusumano said. “I wouldn’t dream of doing that. I wouldn’t do it at the dock, much less take it out on the water. It would tip over with the first turn.”

Each Independence Day, vessels crowd the Long Island Sound shoreline to watch public and private fireworks displays. When the shows end, the exodus can be the nautical equivalent of a highway traffic jam.

Another boater told Newsday he saw the yacht turn and then tip over after it was hit by a wake.

“It was like in slow motion,” said Sammy Balasso of Oyster Bay. “All of a sudden, a lot of bodies were in the water.”

Balasso said he put the spotlight of his 38-foot speedboat on the capsized vessel and threw all the life jackets he had into the water. He said he rescued 20 people.

Azzata said the boat should have had a life jacket for each person on board, but it was unclear whether it did. Under state law, children under 12 are not required to wear life vests if they are in the main cabin, where the three victims were.