Complex sentence: Analysis of these detections determined they did not match the nominal characteristics of the ULBs; although unlikely, experts determine they may have originated from a damaged ULB and a sonar search of the seafloor begins on 14 April.
Split into simpler sentences: Analysis of these signals determined they did not match the nominal characteristics of the ULBs; although unlikely, experts determine they may have originated from a damaged ULB. A sonar search of the seafloor begins on 14 April.