LOVELAND, Colo. -- What began as a fun weekend outing at Boyd Lake ended in tragedy Saturday, when a 21 year old man who was swimming with a family member drowned.

"They had swum out to the buoys at the end of the swim beach and were on their way back," said Don Nadow of the Larimer County Sheriff's Office.

The Loveland Dive Team received a call from dispatch at 12:06 p.m. - There was a swimmer in trouble.

"Family members said that he wasn't a real strong swimmer," said Deputy Fire Marshal Scott Pringle. "So it's possible that he started to experience fatigue."

"On the way back from the buoys, he grabbed on to the other family member for help, then went under water and did not resurface," Nadow said.

While dive team members searched the lake and paramedic crews readied the gurney, family members tried to console each other.

The victim was found at 12:48 in about 6 feet of water. He'd been under the surface for about 42 minutes.

Authorities have not released his name.

They are cautioning other swimmers to know their limitations before going into deep water.

"First and foremost," Pringle said, "if you're going to be in the water, you need to learn to swim and be a confident and capable swimmer. Anytime you're going to be on the surface of the water, it's good to have a life jacket on."

"You just need to know your limitations, Nadow added. "And scout things out before you go into the water and swim a long distance."