The Strange Swimming Coach — Jerry B. Jenkins

This is the fifth book in the adventures of twelve-year-old Dallas O'Neil and his Baker Street Sports Club! You're in for a treat, following Dallas and the gang as they solve yet another sticky mystery. The Baker Street Sports Club needs a coach if the team is going to have any luck at all in the state swimming competition. Dallas has found the perfect man for the job, but how can he talk him into helping? And why does the man seem so bitter? He has a limp he won't talk about, and he never smiles, but Dallas is certain he's the key to the team's success.