the line in hand over hand; hand-wrap reels are the least effective at fighting arrowed fish, but they can be used in conjunction with a float system to shoot and fight large trophy fish. Retriever reels have a "bottle" which holds the line in place. When shot the line comes out either until the shot goes too far and the line runs out or the hunter pushes down a stopping device which can be used to keep a fish from traveling out too far. Some retriever reels have slots cut in them and are known as slotted retriever reels. They are more commonly used for alligator, alligator gar, shark and other big game that will take more time to chase down than smaller game fish. Boats Although bowfishing can be done from the shore, bowfishers most often shoot from boats. Flat bottom "john boats" and canoes are used in areas of low water, as they have less draw, but are unsuitable for open water. Larger boats can accommodate multiple hunters. Many of these boats are highly customized specifically for bowfishing, with raised shooting platforms, and generators to provide electrical power to multiple lights for bowfishing at night. In dense marshlands that are unfriendly to boat propellers, airboats, which incorporate top-mounted fan propulsion for operating in very shallow waters, are usually used. Techniques Along with fishing from boats and off the shore, wading and shooting is also effective as long as the hunter does not mind getting soaked. Wading in rivers allows the shooter to get up close to the fish if the hunter is skillful. When keeping fish while wading, the hunter may utilize a stringer tied to a belt loop. Standing on large rocks in shallower parts of a river is another technique. This provides a better view higher out of the water. Going from rock to rock in a river with two hunters gets the fish moving if they are inactive. It is similar to herding the fish to the other hunter; while one hunter is wading the other is stationary on a rock. All of these river techniques typically work best for carp or catfish, depending on the location. Aiming Due to the light refraction at the water surface and the optical distortion of the apparent position of underwater objects (which would appear to be shallower), aiming straight at the target silhouette usually results in a miss.