With Walter Payton standing by, movie tough-guy Chuck Norris took the helm Thursday as the dynamic duo set out on a mission: to set a world speedboat record.

Too bad the boat didn`t have the same endurance that allowed Payton to set the NFL all-time record for running the football.

In orange helmets and life jackets, the pair sped off at 7:03 a.m. for an ''assault on the Great Lakes,'' a 605-mile journey to Detroit.

To set the record, they had to arrive in less than 12 hours 34 minutes 41 seconds, the record set in 1983 by Michael Reagan, son of the former president. He covered the distance in a 38-foot Scarab powered by triple-gasoline engines.

Payton and Norris had technical difficulties along the way, said Gary Litchman, spokesman for United Way. They docked at about 10:45 p.m. at Hart Plaza on the Detroit River in downtown Detroit.

The Chicago skyline gleaming in the early-morning sun served as a dramatic backdrop as Payton and Norris cruised past Navy Pier to begin their race against the clock.

Their bright-yellow 46-foot power boat left a showery wake as it crossed the starting line and headed northeast in calm Lake Michigan waters.

The two men hoped to average 70 miles an hour as they followed a horseshoe-shaped route around Michigan to Lake Huron and Detroit.

Before embarking, Norris said they were doing it for ''the challenge.''

Payton was silent as he and Norris awaited their cue to head for the starting line.

Asked whether he could swim, Payton said: ''Contrary to what a lot of people might think, I can swim. Do I enjoy swimming? No.''

''We don`t like to lose,'' Norris said.

Thursday`s race was a fund-raising event for the United Way, one of Payton`s and Norris` favorite charities.