It doesn’t take much of a genius to read water like this (above). Obviously, there’s a tide rip in progress as the current sweeps around this headland. It’s a lot trickier to see the tiny wind-ripples. These run at right-angles to the true wind (try blowing onto a big bowl of soup), they’re there all the time, and once you can read them you can tell at a glance what the wind direction really is. This is vital if you’re setting up to go for a mooring under sail or are dead-running and concerned about coming by the lee. All the onboard data—electronic or physical—read apparent wind, which is useful for setting sails, but not much good for anything else. A wind indicator might have a true wind option, but trying to judge numbers and turn them into decisions is a lot harder than using your eyes.