FBI divers and New York police say their efforts to retrieve a yacht that capsized and sank, killing three children, will resume Wednesday.

Officials said earlier Tuesday that divers were having difficulty securing the 34-foot Kandi Won. It is about 60 feet below the surface of Oyster Bay, off Long Island. The rear end of the boat appears stuck on the seabed floor.

It sank July 4 with 27 people onboard following a fireworks display.

The three young children were trapped inside the vessel’s cabin when it sank. Funerals for them were held Monday and Tuesday.

Investigators want to retrieve the vessel to assist their investigation into how it capsized.

The operator of the boat has said a large wave tipped it as a storm approached.