Free fish finder tools: sonar logs, tracks and depths

Tools for anglers and boaters who record sonar logs on their fish finder and want to look at them away from the boat: at home on a Mac or PC, on a phone, or together with a friend who has a different unit.

The sonar log viewer opens the .sl2, .sl3 and .slg logs of Lowrance, Simrad and B&G units without installing anything. It draws the 2D sonar, down scan and side scan as pictures with a depth scale and time and distance marks, so you can find the drop-off, the weed edge or the school of fish again, and share the pictures with others. The track comes out as a GPX file with the depth and water temperature at every point, for mapping apps and GPS software, and as KML for Google Earth.

A depth map shows the depths along the track, coloured from shallow to deep, and a CSV file lists every ping with its time, position, depth, speed and temperature for your own charts in Excel. Damaged or cut-off logs are read as far as they go.

← All tools