HAMPDEN – A 24-foot-long boat took on water and came close to sinking on the Penobscot River on Tuesday afternoon before it was towed to shore and safety.

All five people on the cabin cruiser were uninjured and there were floatation devices onboard, although authorities determined that the registration on the boat actually belonged on another boat. Co-owner and captain Michael Curtis, 40, of Holden was summoned for operating an unregistered watercraft.

The boat recently had been repaired and the five were out testing its water-worthiness, according to Hampden police Sgt. Scott Webber.

Curtis and others said that partway through their trip and as they were approaching Eastern Fine Paper in Brewer, the 4-inch bellows – that help to keep water out of the boat – cracked. It was a sound Curtis said he’ll never forget.

Water then began flowing in. Curtis called for help on a cellular phone while passenger Rick Chapman called his brother, whose own boat was near the Sea Dog Brewing Co. in Bangor. Dana Chapman towed the sinking cabin cruiser back to the Turtle Head Marina in Hampden.

“If it wasn’t for him, we would have gone down,” said passenger Ronnie Robertson of Clifton.

Webber said when he arrived at the marina, the boat was still about 300 feet from shore and floating low in the water. The stern was about six to eight inches above the water level, causing the bow to tip in the air.

After the boat reached land, it took about 15 minutes for all the water to run out, Webber said.