The anguish of the next of kin following a drowning is made worse waiting for their loved-one to be recovered. Underwater searches usually require specially trained and equipped divers to first search and then make a recovery. This task is hampered by extremely poor visibility conditions. Most often search and recovery activities are limited to daylight hours, further adding to the stress of the family. In cases where an exact location is unknown, the search may take days or weeks.
The North Carolina Canine Emergency Response Team (NC K9 E.R.T.) uses a Sea Scan® PC Side Scan sonar to quickly search large areas of rivers, lakes and ponds. A three-man team with a boat speed of approximately three miles per hour can search the equivalent of 40 football fields in one hour, and warn divers about potential hazards, and obstructions. Diving is safer and more efficient. Recovery times could be reduced from days to hours.
NC K9 E.R.T. deploys the side scan sonar eight to ten times per year for both body and evidence recoveries. In addition, NC K9 E.R.T. Side Scan Team has assisted agencies in other counties including Beaufort, Bertie, North Hampton, Harnett, Lenoir, and Wake.
How Does Side Scan Sonar Work?
Underwater, light is quickly diffused and very ineffective. Even the brightest lights yield only a few feet of visibility. A good analogy is driving a vehicle in heavy fog. Headlights are nearly useless, but sound travels well in the fog, and even better underwater. The best way to “see” underwater is with sound.
Side scan sonar is a carefully engineered sonar designed to look through the water sideways, from both sides of a towed unit, to scan the bottom and return images to the surface. A computer processes the data and trained operators interpret the data and determine if the returned data is the target. Once the operator finds a target, it is marked and the team makes several passes to determine the exact position. This makes it very easy for the divers to find the exact spot to make the recovery.