SIDE SCAN SONAR
DROWNING VICTIM SEARCHES
NEW TOOLS AND
FOR UNDERWATER SEARCHING
Law enforcement and search and rescue personnel are frequently required to search for drowning victims as well as missing objects underwater. Typically these searches have been conducted using divers, underwater cameras, and water-trained search dogs. Underwater searching by divers is time consuming and can be very dangerous depending upon water depth, visibility, current, and underwater obstructions.
The lack of good “point last seen” information can extend the search area to tens or hundreds of acres. Often the search area is large because there are no eyewitnesses or the eyewitnesses cannot accurately identify the place where the drowning victim or object was last seen. Large areas are often impossible to effectively search with traditional techniques and consequently searches are terminated after several days and recovery is left to chance.
Gene Ralston, an environmental consultant who specializes in water related environmental issues, has frequently volunteered his equipment and time to assist the Idaho Mountain Search and Rescue Unit, local and national authorities in searching for drowning victims. In early 1999, Gene had the opportunity to experience the successful use of side scan sonar to search for a drowning victim.
Recently, side scan sonar systems have been developed using medical ultrasound technology to dramatically increase resolution of targets such as drowning victims.
The Side scan sonar system's transducer is housed in a towfish, which is towed through the water a few feet above the bottom. The reflected acoustic returns are processed into an image similar to an aerial photograph, which is viewed real-time on a computer monitor in the towing vessel. Typically, the side scan sonar searches a swath 60 to 160 feet wide at about 2 miles per hour, although other ranges can be used depending upon the size of the object being sought.
Location information from a differentially corrected global positioning system (DGPS) is used to guide the towing vessel along predetermined search lines as well as to identify the location of any point on the side scan image. The stored GPS location information allows the searchers to return to any point in the image for further investigation or recovery.
Gene recognized not only that the new side scan technology would be useful to his clients, but also that it would be of great assistance in search and rescue activities. He had a special towfish and variable speed hoist custom manufactured for deep water operation. The side scan sonar he uses was custom manufactured. The custom stainless steel towfish has been used to search as deep as 850 feet. A second, lighter weight aluminum towfish can be hand deployed if necessary in shallower water.
The hoist drum has more than 900 feet of electro-mechanical cable for deploying the towfish in deep water. During the first year of operation, the Ralstons participated in 16 search missions from California to Maryland. Recent search activities have included assisting NASA in the search for space shuttle Columbia debris in Toledo Bend Reservoir on the Texas Louisiana border. The Ralstons have also assisted the FBI and other law enforcement agencies with the search and recovery of multiple homicide victims. During the last fourteen years, Gene and Sandy have located the remains of 98 people.
The Ralston's travel nationwide with their boat and custom motorhome.
At the request of Rich County, Utah, Search and Rescue, Gene conducted a search for a drowning victim in Bear Lake. The victim had drowned more than six weeks earlier and local authorities had called off the official search. Within a few hours of beginning the search, the victim was located in 148 feet of water in an area just outside of the area searched by an underwater remote operated vehicle (ROV) and camera. The ROV was later used to recover the 24 year old man. See Bear Lake for further details about this search.
The National Park Service has requested Gene and his crew on several occasions to assist in the search for drowning victims on Lake Powell and Lake Mead. Water depth and very irregular underwater terrain complicate the Lake Powell and Lake Mead searches. During one search on Lake Powell, the victim was found in 286 feet of water on the morning of the second day of searching. The National Park Service's ROV was used to recover his body. See Lake Powell for more details. Four drowning victims were recovered from Lake Mead in 2002.
Recent underwater searches of note include the successful recovery of a man who had been missing for more than three years; the discovery of a 1927 Chevrolet sedan that disappeared in Lake Crescent, Washington, in 1929 and discovery of a person who appears to have been missing as long as one hundred years in nearly 350 feet of water.
The Ralstons recently purchased a remote operated vehicle (ROV) to assist with the recovery of drowning victims. Once the side scan identifies an object of interest, the ROV can be used to inspect and recover the object. The OUTLAND 1000 has 500 feet of umbilical cable and is outfitted with a high resolution color and black and white video camera. Two weeks after they had received the ROV, they used it to recover a drowning victim in Lake Pend Oreille in northern Idaho. The man was in 160 feet of water.
Follow these links to read news stories about recent underwater searches:
Car in lake may solve 72 year mystery
Three drowning victims recovered from two Oregon lakes
The Search for Laci Peterson
Search for a man missing in Auke Bay, Juneau, Alaska
"They are, instead, caretakers of dignity who bring loved ones back to their families"
Amazing discovery in Priest Lake, Idaho
Man recovered from Lake Pend Oreille
IDAHO SEARCH TEAM FINDS BODY ALMOST IMMEDIATELY Lake Cumberland, KY
Searching for Kathy and Travis The Ralston's have re-christened their search and recovery vessel Kathy G in memory of Kathy
Volunteers Travel North America finding the dead Little Bonne Bay Pond, Newfoundland. Blue Line Magazine, CANADA
The Stephan Hopkins Memorial Foundation During the summer of 2007, tragedy struck the province when 19-year old Stephan
Hopkins drowned in a boating accident near a friend’s cabin. The popular hockey all-star had tried in vain to swim ashore after
the canoe he had been paddling capsized on a July evening.
Fort McMurray - in the right place at the right time.
Underwater Technology Used to Bring Closure to Families of Drowning Victims The Journal of Underwater Technology, 2010
The benefits of using side scan sonar to search for drowning victims and other objects underwater, include being able to search a large area quickly and safely. Divers are not placed at risk during the search operation and are only deployed for the recovery once the object is found. The side scan sonar images are also useful to evaluate any hazards to divers before they enter the water.
The Ralstons offer the use of their equipment through the Idaho Mountain Search & Rescue Unit, as well as their company Ralston & Associates. If your need is immediate, please call (208) 362-1303. If we are out of the office, we may not have email access for several days. If you have a general question which may not need answering for a while, you may phone or email us at:
Side scan sonar image review is provided as a free service to anyone who would like assistance in sonar image interpretation. Gene has found five drowning victims in images made by other agencies. On-site training in the use of side scan sonar can also be provided.
Bears made from the clothing our loved ones left behind for us.
Janet Keller eases the pain of grieving parents with teddy bears made from old clothes of their lost loved one.
"Janet has made these bears for several years now. It started with making bears for her 3 kids as a gift for them on the 10th anniversary of her son Joe's death in 1994 from trying to save his friend from a low-head dam. They were made from clothing that he had "borrowed" from them."
Drowning Support Network
If you have lost a loved one to a drowning incident or other aquatic accident and need information or assistance please consider joining the Drowning Support Network. Nancy Rigg, a writer, documentary filmmaker, and flood safety education consultant, whose fiancé lost his life attempting to rescue a child from a flood-swollen river, is the moderator. The Drowning Support Network is a peer support group of families who have lost loved ones in incidents involving drowning, especially when no physical remains have been recovered... We hope that by joining together, we can not only lend one another support, but also lobby for change in the way these emergencies are handled, including the effort to recover the remains of our loved ones.
Click to subscribe to DrowningSupportNetwork