CHARLESTON -- Bradley County Deputy Jamie Thurman remembers a sunny summer day that turned dark a few years ago.

He and his partner were on a boat patrolling the Hiwassee River when they got a call that a man had belly-flopped off a cliff into the water and not come up.

By the time they reached his location, the man had been under water for more than five minutes.

While family and friends cried, the pair stood helpless. They had no dive gear or training to go into the 20-foot-deep water. They knew people who are drowning often will drag a rescuer under with them.

The man couldn't be saved.

"That's the worst feeling: You're there but you're not able to do anything," Deputy Thurman said.

This year things are different.

Since last fall, deputies Thurman and Sam Collins and Detective Carl Maskew have trained in basic SCUBA diving. They've learned techniques for rescue, recovery and underwater mapping.

Recently, they began mapping the underwater landscape of popular swimming and boating spots along the 33-mile stretch of the river that forms the northern border of Bradley County.

The marine unit was formed nearly eight years ago as a response to riverside burglaries in subdivisions that lined the waterway, Deputy Thurman said.

Sheriff Tim Gobble said equipment and initial training for the divers cost about $3,000. He said the men can search for dumped evidence such as weapons, cars or drugs.

The work a lot on training.

They practice quick-rescue techniques, called "pop dives," in case they're called for a downed swimmer, fisherman or skier.

Deputy Collins said a diver will quickly throw on a mask, fins, tank and buoyancy compensator vest that helps him quickly float or sink. Once in the water, he drops straight down at the point where the downed person was last seen.

The Hiwassee doesn't flow as quickly as larger rivers unless there's been a lot of rain, Deputy Thurman said. A person would likely drift less than 10 feet from the spot he or she entered the water.

They also work on evidence and body recovery, which means more equipment.

In recovery dives, pairs of divers team up and swim a zig-zag pattern in what's called a grid search, Deputy Thurman said.

Thursday evening as Deputy Thurman piloted the patrol boat, Deputy Collins and Detective Maskew wriggled into wetsuits and donned gear. They were on an expedition to find out what was under "the bluffs" -- a popular spot where some swimmers jump off the 20-foot cliff.

Most of the river use comes on the weekend, so the two deputies work Friday through Sunday from 9 a.m. to 11 p.m.

"People say, 'You've got the best job,' but while they're out there having fun, we can't," Deputy Thurman said. "We just sit here in the heat watching them."