#QuickTips - The Best Technique for Scanning the Water
By: Captain Bill Jennings
Whether boating on a small lake or the open sea, you are always keeping an eye out for traffic and obstacles in the water. Did you know that there are a number of different ways for boaters perform this basic 'look-out' procedure? Maritime researchers have conducted some interesting studies to learn the best way to scan the water while looking for things to avoid.
A common conclusion to these studies is that the eye and the brain can only focus on one thing at a time. To properly identify what is in your vision, you have to stop your eyes in a single direction and not just sweep your gaze. If you move your eyes in a continuous sweeping motion across an area, your brain cannot identify individual items accurately. Sweeping your vision around without focusing on anything in particular will not tell you everything you need to know.
From this data, the best procedure for maintaining a proper lookout when boating is to look at one 30 degree sector at a time and focus your attention on a fixed spot in this sector for 1 to 2 seconds. Then move on to another sector, and so on.
In other words, focus your attention in a series of short, regularly-spaced eye movements that bring successive areas of the water ahead into the central visual field. Each section viewed should not exceed 30 degrees and should be observed for 1-2 full seconds to enable detection.
This technique makes it easier to spot objects that are moving as well as stationary objects that are more likely to be overlooked. You can generally avoid most collision risk by scanning an area at least 90° to the left and right of your intended path.
You can start your start/stop scan at the 270 degree position to port, then focus in each of six segments over to your 90 degree position to starboard. This covers three distinct segments to your left and three to your right. You can also choose forward to side scanning, where you begin by looking ahead and move to segments on your left, then focus back forward and move through segments on your right. The important thing is to stop your eyes for 1-2 seconds before moving to the next segment.
Once you spot another boat, watch it long enough to identify its direction of travel and any keynote details (is it towing a skier, does it have fishing lines in the water, etc). Remember, if a boat you are watching shows no relative movement versus yours, you are likely on a converging course.
Understanding and utilizing simple boating techniques like this will give you a leg up on other boaters and help keep you safe.