It's not easy taking the materials you might normally use in moving an apartment and making them buoyant enough to float in several feet of water.

Just ask the participants in the 21st annual Cardboard Boat Race Sunday at Fox Lake's Lakefront Park.

For the better part of Sunday morning, the contestants and their friends and family labored intensely, using cardboard and duct tape to fashion crafts sturdy enough to stay above water.

Gabby Ross and Bre Retherford of Spring Grove, competing for the first time, had their secret weapon -- cardboard tubing for paddles.

"Paddling is the key to success," Retherford said.

Laura Linehan, assistant to Fox Lake's village administrator, said contestants received large sheets of cardboard, four cardboard corners to help with structure of the boat, a box cutter and duct tape to construct their watercraft.

As many as 25 entries were expected to take part in the races, she said.

Participants received honors not only for the longest time afloat, but also for "fastest sinking" and design. Life jackets were mandatory.

Among those building boats Sunday morning was Kim Sutfin of Fox Lake.

"It's so fun. I don't know why more people don't do it. It's a blast," she said.

Several contestants arrived with pre-made boats, including one group of softball players.

Jennie Woodruff, 13, of Spring Grove, said their boat displayed a softball theme, with the craft sporting softball stitching, two crossed baseball bats and a softball jersey.

Woodruff said the boats are challenging to put together.

"There is a lot of math to it," she said, adding that it took the group from Monday through Thursday to complete it at their houses.

Despite the labor involved, the boaters couldn't have enjoyed better weather, with clear, sunny skies and mild temperatures.

Spectators and boaters alike could also enjoy brats and hot dogs fresh off the grill.