This will convert your coordinates to something H/B can use. http://www.earthpoint.us/convert.aspx Use the conversion with the first 2 numbers, followed by the decimal point and 7 more digits. Like this, 33.2397806° Humminbird will only allow 5 places after the decimal point, so you will have to drop the last 2 numbers. So your entry should look like this, 33.23978° Are you using Humminbird PC to enter the coordinates? If so, use "edit", "preferences", "position format" to get the format like this 33.23978°