Safe at Sea: Night sight
The last few columns have discussed “sea sight” and have emphasized that seeing things well on the water takes more than knowing where to look. Primarily, the columns have dealt with seeing in the daytime. At night, some additional things are important.
While our eyes adjust quite quickly to bright light, they take much longer to adjust to night time light levels. For example, if you have been in bright light, it takes close to a quarter of an hour for your eyes to adjust completely.
Here are some things one can do to improve your night sight.
Remember: flashlights, spotlights, cell phone flashlights, et cetera, are all enemies of night vision, and you should avoid looking at them. A navigator checking lights and then using a chart has a hard time keeping good night vision. Paradoxically, a dim light makes it difficult to read the chart, and a bright light ruins one’s night vision.
At night, a captain is often searching for a distant light. The best technique for this is to use the same “spot-by-spot” search used in daylight. While it is a challenge to keep track of a spot on the horizon, stars make good points of reference. The center of the visual field, best for seeing fine details, is not quite as good as the surrounding area for seeing in dim light. Therefore, look slightly above or below the horizon when searching for a light.
If you are looking for an unlighted object, use the reflected light from the waves to silhouette it. This isn’t possible unless you have some light in the background, but only a little is needed. The moon, shore lights, even starlight or the loom of a city may be enough to outline a dark object. This is a particularly important technique when entering or leaving port at night. It works well and does not ruin your night vision.
All the prior discussion about “sea sight” leads to an ending note: binoculars.
Like sunglasses, buy high quality. A cheap pair of binoculars is never a “good bargain.” They will simply hamper your ability to see well — day or night.
Finally, use good optical equipment and good search techniques, and you can develop your sea vision to its maximum limit. That will open a world of interesting sights, things that you will never see unless you know how to look.
Pat Schmidt is a member of America’s Boating Club of Sanibel-Captiva. For more about the chapter and its courses, visit www.sancapboating.club or contact education@sanibelcaptivasps.org or 612-987-2125.