In 1996, 230 accidents on Maryland waters led to 23 deaths and 129 injuries. Most of the deaths - 21 of 23 - were the result of drowning. And most of the drowning victims were not wearing life jackets, according to the department.
Manown admits to becoming particularly irate when parents don't pay attention to their kids. In places like Dam No. 4, boats are continually coming in and out, making it a real hazard, she said.
Wolfe, 21, of Hagerstown, concurred. He had the day off from his job with S&S Drywall, but had work to do watching out for the adolescent boys, who belonged to his colleague.
"I only let them out 15 feet away from the dock, if that," because of the current, he said. They wore life jackets to avoid risks. "If they got in trouble, then I'd have to get in and save them," he said.
No-wake zones were created five years ago to make boating ramps more safe. They require boats to slow down and reduce wakes, or waves, in areas where people swim or put boats in the water.
Dam No. 4's ramp is in a no-wake zone, although you wouldn't have known it Friday.
"They don't obey the no-wake zone," complained 9-year-old Ashley Powers, pointing across the river to a jet-powered speed boat spitting back a rooster tail of water.
"The wake can make swimming really dangerous. Eeew, and look at the oil. It's disgusting," she concluded.
Sporting purple round-rimmed glasses and a bright lemon and lime floral bathing suit, Powers listed other water hazards: "What else is dangerous is if you get near the motor when tubing? Also you shouldn't splash the deck, people can slip. And trash in the water can screw up the boat."
Powers was at Dam No. 4 as part of summer camp.
She and campers Jessica Johnson, 9, of Annapolis, and Kelly Mangum, 10, of the District of Columbia, were learning water safety. "Give the OK sign," they giggled, and in synch put their arms overhead in an "O."
Ryan Prentice, their camp leader, explained when they wipe out water skiing or fall off an inner tube, raising their arms up means they didn't get hurt.
Manown identified jet skis and personal water craft as the department's fastest growing concern.
"People think of them as a great big toy, jumping the wake behind boats. They lose sight of the fact that they're a vessel."
Operators have to obey the same rules as boaters, or risk being fined, she said.
Natural Resources Sgt. Greg Bartles said rules include a maximum weekend and holiday speed limit of 35 knots, or 41 mph. "High performance personal water craft will go 60 knots, or more."
Disobeying the rules, he said, could lead to fines: $40 for speeding or breaking the no wake rule; $50 for tubing down the river or jet skiing without a life vest; $50 for skiing after dark or failing to use lights at night.
The department asks drivers to slow down, don't drink, wear life jackets, check safety equipment and pay close attention to swimmers and tubers.
DNR officers called Friday "a below-average boating day" with no major incidents. However, officers think activity will increase today.