"I Could Do It” allows the audience to get their hands dirty at the controls of machines they have always admired. It introduces viewers to the way machines work through the people who work them. Have you ever wanted to put on a pair of steel toed boats, march over to a construction site and hoist a crane? Or is the life of a tugboat captain more than up your alley? Now, viewers have a chance to take a plunge and get down and dirty with the machines that make the world go around. Watch “I could do it” on Discovery Turbo tonight at 9 p.m.