I use the 3D and side for finding structure and bottom changes. I thin go back over it zoomed in or over it with the 2Dchirp and down vision.

Lets look at a 9 inch screen its measured Diagonally, so figure 8.5 inches across.

On a 80 ft scale, if whe're in 20 ft of water 1/5 of the screen will be the water column. _ _ _ _| |_ _ _ _ left a space so you can see each 20 ft section. 4 along the bottom and two spaces for the water column.

So fo every inch along the screen is roughly 20 ft. 1/2 an inch would be 10 ft, 1/4 of an inch would be 5 ft, adn 1/8 of an inch representing 2.5 ft.

If a fish is parallel to the transducer and 3 to 5 inches wide or perpendicular to the transducer and is 20 inches you can see how small a spot it will be on the screen when looking for fish.

Find the structure, and then zoom in on it to look for the fish.