Jun. 20—NEWBURYPORT — Local police and Newburyport Harbormaster Paul Hogg are investigating what caused Raven II, the Fire Department’s boat, to sink sometime overnight Thursday while docked at Cashman Park.

A pedestrian walking around 4 a.m. noticed the boat partially submerged and listing severely to port. Newburyport police, firefighters and Hogg arrived on scene minutes later. A TowBoatUS crew was dispatched to the area as well.

The vessel, designated Newburyport Marine 1, is a 2007 MetalCraft Marine FireStorm 30 high speed aluminum fireboat. It was acquired in 2020 after serving in the Portsmouth Fire Department. Raven II is the second Newburyport fire boat to be named after Newburyport firefighter Tony Raven, who died after battling a fire on Chapel Street in 2016.

Newburyport fire Chief Christopher LeClaire said the vessel was in use during the recent search for a missing 6-year-old boy last seen with his family on Deer Island. The boy and his mother drowned. Firefighters also trained on it Thursday, hours before it sank, he added.

“No issues when they parked it,” LeClaire said.

The tide was outgoing at the time, with high tide occurring at 2:09 a.m. in Newburyport. Low tide was anticipated at just before 9 a.m.

After listing to the side, the boat eventually sank to the bottom, sliding underneath a dock in the process. The dock did not break. Around 9 a.m. TowBoatUS personnel lifted the boat from the bottom of the river, pumping air into yellow and gray inflatable bags placed underneath it. Others were busy pumping out water.

As of 10 a.m. officials were determining whether the vessel will be able to towed away to a nearby marina for examination or whether it will have to be dragged to the adjacent Cashman Park boat landing. Investigators will also determine if Marine 1 will be suitable to return to service.

The sinking drew a sizable but transient crowd of onlookers, some of whom took photos of the recovery operation. The public boat launch remained open.