A father and son were rescued from the Boston Harbor after they were found by police clinging onto a blue cooler on Wednesday evening.

The Boston Police Harbor Unit received a call on Wednesday at 6:35 p.m. about "a boat taking on water and sinking off the coast of Graves Light in Boston Harbor," according to a news release.

When they arrived, officers found a boat almost completely submerged in water and two men holding onto a floating blue cooler.

Video of the rescue obtained by NBC News shows the moment the officers found the two men.

"Help him up first," the son is heard telling the officers about his father.

A man wearing a life jacket who said he was 76 years old was then pulled onto the police boat.

“I’ve got no strength," the man can be heard saying.

The officers then turn their attention to the 38-year-old son, who also struggled to get into the boat. The father and son pair, who confirmed they were the only two on their boat when it sank, can be heard thanking the officers.

After the men were pulled to safety, they reported that their boat's engine became tangled in lobster lines and began to sink, causing them to abandon ship, according to police.

The men were transported to shore where they were treated by an EMS team. Their boat was also lifted and taken to Thompson’s Island, police said.

Mirna Alsharif is a breaking news reporter for NBC News.