A crane placing a barge into the water off the East Boston seashore collapsed, dropping the barge onto another boat, authorities said. No one was injured.

The collapse happened shortly after 11 a.m. at the Boston Harbor Shipyard and Marina, a private business situated on Massport property in Eastie, according to Massachusetts State Police spokesman Tim McGuirk. The address of the business is 256 Marginal St.

McGuirk said that in addition to the Fire Department, MSP Troop F and the Marine Unit responded to the collapse. The crane was placing a barge into the waterway when it collapsed, causing the barge to slip and damage a moored boat with no occupants.

Boston Fire Department Commissioner Paul Burke told reporters at the scene that several of the straps between the crane and a barge — which he estimated weighs five tons — “let go.”

“It slid down pretty forcefully into the water because it’s a heavy piece of equipment,” Burke said.

Burke said there were “no injuries at all,” though his department didn’t know that when they rushed to the call and brought a dive team in case the crane operator had fallen into the water.

“Luckily nobody was in that boat, the crane operator’s safe, there was nobody around, no pedestrians walking underneath it,” Burke said. “It’s not secure now so we are waiting for another crane to come in and secure it.”

Boston Police Department spokesman Officer Mark Marron also said that the dock supporting the crane fell halfway off the pier. He then said that it was an MSP matter and directed further questions to that agency.

The Herald reached out to the Shipyard and left a message requesting further comment.

This is a developing story.

Boston Fire Commissioner Paul Burke speaks after a crane collapsed at the Boston Harbor Shipyard & Marina in East Boston. (Photo By Matt Stone/Boston Herald)