Feedback on.... Carp Hunting

Enlarge Image Image Gallery LEFT: Shooting cross the air-water interface (as shown incorrectly in MOTHER NO.33). RIGHT: A correct version.

(Note: As many readers—and the article's author, Richard Reed—have pointed out, "The Fine Art of Stalking the Wild Carp", MOTHER NO. 33, contains a major error. The diagram on page 101, which illustrates the compensation for refraction needed when shooting into shallow water, shows the fish's actual location above its image. Actually, the reverse is true and the hunter must aim low, not high. The mistake was mine, and I apologize . . . both to Richard and to any beginning bowmen who may have returned frustrated from a day of misdirected archery. Among those who called my attention to the goof was Herm Fitz of Blue Riper, Oregon, who sent along the following valuable information on the optics of wetland bow-hunting.—MOTHER.)

In MOTHER NO. 33, Richard Reed ably described the hunting of carp with bow and arrow in shallow water ... and his article has no doubt inspired many readers to take up this sport, which involves shooting across an air-water interface. A single—but flagrant—inaccuracy in MOTHER's presentation will, however, inevitably lead to the failure of any beginner's attempts to pursue the intended prey.

Reed states on page 102, "To shoot at even a clearly visible fish only 8 inches under the surface. . . you must compensate for the refraction of light at the water's surface." This is quite true, but the novice who compensates according to MOTHER's instructions will miss every shot! The diagram which illustrates the author's point (reproduced here as Fig. 1) contains a serious error: The image of the fish should be shown directly above the creature's actual location—not below and beyond, as in the drawing—and the hunter should therefore aim low, not high (see the corrected version in Fig. 2). Moreover, the archer is given no idea of just how much too low to direct his arrow. Since we don't want a bunch of carp-hunters coming home empty-handed, let's look more closely at the phenomenon of shooting into water.

Here's what happens when you peer through the lake's surface at the fat carp you hope to bag: The light rays reflected from the fish under water reach the air-water interface and, upon crossing that boundary, are bent. This phenomenon—known as the refraction of light—results from the light's speeding up as it enters the air. The amount of bending depends on the angle at which the original ray hit the interface; The greater the angle of incidence, the more deviation from its original direction. Thus, when one looks directly down (perpendicular to the surface) on a fish, there is no deviation in the line of sight . . . although the object will appear closer than it actually is. As the horizontal distance from hunter to quarry increases, the deviation gradually increases also, so that the prey seems to be higher and higher above its actual position (see Fig. 3).