Re: Visibility of course marks
The Coast Guard requires our racing marks to be orange and white, but we're on salt water, not a lake. We use orange and white striped plastic highway construction barrels that we attach (screw down) to a square float. One that's a bit further out than the others has two of them stacked. Each is labeled with a big letter on four sides to identify it. Knowing where to look, we can generally pick them out more than a mile off, without binoculars.