FLORIDA KEYS - Two teenagers with a natural affinity for the sea assisted in rescuing two families -- including a 4-year-old boy and 3-month-old baby -- after the boat they were in capsized near the Florida Keys over the weekend.

Mason Baker, 17, Will Coffin, 18, and Will's uncle, Dave Tolhurst, 54, were fishing for Yellowtail just north of the Conch Reef Sanctuary Preservation Area in the upper Keys on Saturday when Tolhurst noticed the 23-foot boat overturned about 500 yards away, Baker told ABC News.

"He asked us, 'Is that boat upside down?'" Baker said, referring to Tolhurst's comment after seeing the overturned boat.

Once they determined that the boat was in distress, the group decided to "go do something" about it and pulled up their anchor, calling the U.S. Coast Guard as they made their way to the scene.

Once they got there, they saw six people in the water, with the captain of the boat trying to climb on top of his capsized vessel, Coffin told ABC News.

The good Samaritans pulled five of the stranded passengers from the water -- including the two young children but minus the captain -- onto their own boat, Coffin explained. The teens were also able to retrieve the group's three coolers, which still had food intact, so they handed out juice and grapes to the 4-year-old boy, who was concerned about his father who was still in the water.

Baker said he gave the "soaking wet" 3-month-old his shirt, and the Coast Guard arrived about 30 minutes later. The Coast Guard then airlifted the baby to a local hospital for the possible ingestion of salt water, officials said.

Baker, whose father is a professional captain, hypothesized that the boat overturned because the six passengers, plus three coolers were too much weight for the small boat to handle. Additionally, conditions on the water were choppier than what was initially predicted that day, he said.

Both families were from out of town, Baker said, and the boat was fairly new.

Tolhurst commended the teens for their boating expertise and for staying calm during the traumatic ordeal, Bonnie Coffin, Will's mom, told ABC News. Bonnie added that one of the victims got hit in the head when the boat overturned and told her son that "five more minutes," and he may not have made it.

The man was "rattled," she said.

The teens' mothers explained the rescue posed a valuable lesson for the boys, who are set to graduate from Coral Shores High School in Tavernier and will attend Florida Atlantic University in Boca Raton in the fall.

"You can see how quickly things can go wrong out there, and you need to be aware -- always -- of your surroundings and always pay attention," Bonnie said, adding that her son is "very cautious" and has good common sense.

Duane Baker, Mason's father, taught him how to "respect the water" and understand the risks involved, his mother, Jill Miranda-Baker, said adding that he plans on taking his boat with him to college.

"His first love is being on the water," Miranda-Baker said of her son.

Mason said he plans on studying criminal justice and hopes to become an officer for the Florida Fish and Wildlife Conservation Commission, while Will said that he plans on majoring in ocean engineering.