Using edited data. Ran mbbackangle -F-1 -I filelist -N137/75 -P25 where 137 = the number of beams(rounded to odd number) and 75 = the angular swath width /2. Then ran process, but had to force the files to be processed as there were no changes in the "esf" files. This didn't produce noticeable results in the sidescan plot. I decided I need to filter the amplitude and sidescan values to remove the spikes. For this I need to use mbfilter, but mbfilter isn't yet capable of utilizing datalists. Therefore, I've written a script, similar to mult-copy, that will read a data list and create the mbfilter commands with output files having an appropriate naming convention.