Hello! I am using a Lowrance Elite 5TI and ReefMaster to generate contour maps and conduct some light-duty bathmetry from an unmanned platform - it seems to work great. However, I have not been able to find any specs/estimates on the accuracy of the Elite 5TI or other similar units. I contacted Lowrance and they were not able to provide any info...

Can anyone provide any input? How accurate are these types of sonar units?

Much appreciated!

The accuracy is a bit of a complicated issue. You need to remember that what you are seeing is the least depth within a circle that represents the footprint of the sonar cone. So while the depth accuracy may be to within a few centimeters if properly calibrated, the location of the point in question is entirely dependent upon the size of the footprint and depth of water. So if you have a large footprint with an undulating bottom it could be entirely unrepresentative of the actual depth in the precise location of the boat.

T

As AC is saying. Accuracy is mostly a question of the ducer used. Wide coneangle ducers like Totalscan and HST-WSBL are not very accurate, narrow cone ducers like Airmar TM260 are very accurate and borders to professional equipment. The deeper the water, the more inaccurate will the wide angle ducers be.