WASSP S3 Multibeam
The WASSP S3 multibeam typically has a swath (bottom coverage of 3 times the depth of water it is in [50m would have 150m coverage]) with its 224 beams (so in the above example a data point approximately every 0.7m)
This is tied with a high accuracy inertial measurement unit (IMU) providing roll pitch heave corrections in association with the GPS (which receives AMSA Marine Beacon Corrections)
Multibeam versatility
The unit has been designed to be self sufficient just requiring a 12V DC power supply and able to be mounted on a variety of vessels and configurations
Data Interpretation
An example of a large hole where a WWII vessel had once laid (in this case 135m long and 3m deep) which had been removed for salvage https://www.theguardian.com/world/2016/nov/16/british-second-world-war-ships-illegal-scavenging-java-sea