Clear water?? Oh yeah, I think I know what you mean.......
Found myself using my compass while in Florida in Feb/Mar this year. Even though the water was clear, I could have easily gotten lost if I had not kept a mental road map of my direction and distance traveled. Seen one corral formation, seen them all. To me they all look very similar. The other two divers on my first dive (3 divers on a six pack boat, we dove together), asked me how I knew where the boat was when we signaled to return. They both said that they were going to surface and look, but followed me instead. I told them and they both had a bit of a stunned look on their faces and admitted that neither of them had a compass, and had not really learned how to use one.
Seems like thats the way most divers make their way back to the boat around their, as I saw quite a few "salt water prairie dogs" popping up to take a look, then swim in the direction of the correct boat under water.