On a hot Saturday afternoon in August, officers Larry Furlong and Sean Sauserman, of the Pennsylvania Fish and Boat Commission, were gearing up for a day on the water.

Their boat, emblazoned with "Law Enforcement" on the side, was parked among pleasure craft at the McKees Port Marina, but the men were all business.

They wore casual tan shirts and green shorts, but underneath they were strapped with bullet-proof vests and on their hips they carried about 20 pounds of gear, including guns.

The two are responsible for patrolling the Monongahela River from Monessen to Pittsburgh. If the waterways were roadways, the men would be police officers, patrolling for those driving recklessly, without licenses or under the influence.

Their jurisdiction also extends to the shore, where they occasionally cite minors for drinking.

The Fish and Boat Commission is just one of many agencies that patrol the three rivers all year. Summer is, of course, the busiest time on the rivers here.

Several local fire departments -- McKeesport, Elizabeth Township, Braddock -- do amphibious duty and are equipped with boats to perform search and rescue missions. Glassport's Citizen Fire Hose Company recently upgraded to a 21-foot boat equipped with rescue equipment.

"We just figured with the increase in boat traffic every year, our 16-foot aluminum was not up to snuff ," Chief Wayne Lewis said.

The U.S. Coast Guard Auxiliary offers boating safety classes to pleasure boaters and to those who may do rescues on the water. They also do free safety inspections.

At least once a week, one of the 39 members of U.S. Coast Guard Auxiliary Division 9 patrols the water, looking for potential violations by commercial craft and making sure navigational aids, such as signs and buoys, are in order. They notify the Coast Guard if they see anything wrong.

The U.S. Coast Guard is responsible for monitoring commercial traffic and maintaining navigational aids, among other things.

On Aug. 23, which Officer Sauserman said was one of the quietest days of the summer season, there were nearly as many barges on the river between McKeesport and Monessen as there were boats. The pair made their way down the river, scouring the waterway for unlicensed fishermen and unsafe boaters and jet skiers.

At the first stop, on a concrete pier in Elizabeth Borough, Officer Sauserman checked the licenses of a few shirtless fishermen.

"Having any luck?" he asked, before asking to see their licenses.

Saturday, the main culprits on the river seemed to be jet skiers. Over the course of the shift the officers pulled over five jet skiers, all for riding too closely to each other or to other boats.

Then, while they had the skiers pulled beside their craft, they checked the skis from front to back, ensuring they had proper licenses and making sure the fire extinguishers were up to code.

At another point, they stopped a pontoon with a fishing rod in the water. The men checked to see if boaters had proper fishing licenses, and also checked if there was a fire extinguisher and enough life jackets on board.

Officer Sauserman informed the boat's owner that she did not have enough life jackets that were up to code and told her to buy new ones if she wanted to continue boating.

"We're just trying to make sure that everybody's safe. That's all," he said.

He said he most often gives warnings and educates those on the water of their infractions, rather than fining them.

But at one point, the potential for danger was just too high for a simple warning.

Officer Furlong wrote a citation for a father and son whose behavior was not safe. The father was driving the pleasure craft with his son directly behind on a jet ski, riding the boat's wake.

"He slows down and you don't see him, you go right up the back," Officer Sauserman told the skier. Between the pair, they racked up more than $400 in fines.

"With this one, there's too much potential that people will get hurt," he said.