What were the most crucial instruments that Crabster used during its deployment at the ferry site? What kind of information did Crabster collect or find during the operation?

Most crucial tool of Crabster in the site was acoustic instrument on the six-legged platform. We could see nothing with ten optical cameras on Crabster. We got acoustic images of sunken Sewol from scanning sonar. We got acoustic images of seabed from acoustic camera. The six-legged Crabster worked well as a stable moving station for the acoustic instrument in tidal current. The Sewol ferry was slanted 90 degrees to port side. The seabed was composed of mud, stones and small pieces of shell. Crabster also acquired depth, altitude, conductivity, temperature. Attitude of body, all joint angles and electric current of six legs were also monitored and recorded in surface control room.