Any person scuba diving in a body of water in which motorboats are operated shall place a buoy in the water at or near the point of submergence. The buoy shall bear a red flag at least twenty-one (21) inches square with a red background and white diagonal stripe that is one-fifth (1/5) the width of the flag. The white stripe must run from the top of the hoist to the bottom of the flag. It is unlawful to display this flag when diving or spear fishing is not in progress.