[Mee-n-Mac]

I find people can be trained to recognize a distance but not many distances. If you're driving down the highway at a semi-legal 68 mph then that's 100ft/second. Find a crack or something and count (slowly) how long it takes to get to you. When you find the distance that equals 1.5 seconds then that's about 150'. When on the water most poeple are running in the 30-35 mph range so double the timing to get the same distance. Just do this when not too much else is happening so you don't run into anything in the process.

As to signs ... I thought I've seen them at the Alton town docks but as was said most people don't pay attention to the signs. The buoys off the docks are a good idea if only because someone might ask "what are those for ?".