Whenever you catch a fish, note the depth and other information provided by the depthfinder. This will teach you the importance of depth in a fishing pattern. When you purchase a depthfinder, study the instruction manual carefully. Ask the salesman for additional instructions in interpreting the unit. Even better, spend some time on the water with a fisherman who is experienced in interpreting the kind of depthfinder you select.
Some models also can show the surface temperature of the water and boat speed.
It shows bottom depth and positions of suspended objects such as fish via red lights on a dial similar to a clock face. Some anglers skilled in interpreting flasher depthfinders find that these units meet all their fish-finding needs. They have become extremely popular because they help an angler visualize the bottom and the position of fish near the bottom. LCD units usually are waterproof and durable, since these contain no moving parts to wear out. They range in sophistication from small, basic units that show the bottom to large-screen information centers that can zoom in on fish and even show water temperature and boat speed.