im sorry ljones, i wasn't thinking, i should have posted what unit im using. its a humminbird 998. in this picture theres 1"X2"boards nailed together with the hight of the boards being about 3' tall . i think that in this picture the boat speed was around 3mph with sensitivity set to 1 and contrast was either 9 or 10. default setting really work the best but i cant keep from tinkering around with the settings.