Police agencies and the Coast Guard kept busy over the weekend delivering boaters to safety after marine mishaps, but they're bracing for an even more hectic time with the July Fourth holiday.

Crowded boating lanes, nighttime fireworks displays and alcohol are among the factors that can make the extended holiday weekend a particularly dangerous time on Indiana waters, officers said Monday.

Along Lake Michigan, that danger starts as early as Thursday night, when the city of Chicago puts on its fireworks display on the eve of the holiday, said Officer Frank Dupey of the Lake County Sheriff's Department Marine Division.

"It's not uncommon to have several hundred boats sitting in one spot. That leads to bad problems sometimes, especially if there's alcohol and speed involved," Dupey said.

Lake County and the Coast Guard were among the agencies Sunday that rescued five people off a breakwall after a fishing boat smashed into rocks and started to sink near U.S. Steel's Gary Works.

Meanwhile, at the opposite end of the state, at Brookville Reservoir in southeastern Indiana, a 34-foot boat drove over a woman on an innertube behind a boat. Twenty-year-old Ashley Hilton of Pendleton was in stable condition Monday after surgery at a Dayton, Ohio, hospital, said Conservation Officer Angela Goldman.

And on Lake Wawasee in north central Indiana, Gary K. Froshaug, 62, of Fort Wayne died when rough water and strong winds capsized his sailboat Sunday. Two others on the boat were rescued, conservation officers said.

Quickly changing weather conditions are a common cause of boating mishaps. Rescuers pulled a 22-year-old woman from Lake Michigan on Saturday an hour after strong winds and waves caused her to float away from her father's catamaran, police said.

"Within a matter of minutes she can get very angry and kick up the waves," Dupey said of Lake Michigan.

That also applies to smaller bodies of water, Goldman said.

"The weather can change so rapidly on the water. People get out, they don't look at the weather, and they get in trouble because of the weather," she said.

The Department of Natural Resources will have extra conservation officers during the holiday weekend on lakes, reservoirs and major rivers, Goldman said.

She recommended boaters check out their vessel for safety before they even leave home if they're towing it to a ramp.

The Coast Guard also will have an increased presence and will be boarding boats randomly for spot safety inspections, said Chief Jim Ellison of the Guard's Michigan City station.