In most cases, a 911 call reporting a drowning on a lake or in a river means recovery. But a couple of developments might make departments reconsider their approach to these responses.

The first is that there's a changing understanding in how fast drowning occurs. Typically, a drowning victim will die in less than six minutes from a lack of oxygen. However, something called Mammalian Dive Reflex may keep submerged people alive for 60 minutes or longer. According to WebMD, when a body plunges into water 70°F or colder, its metabolism slows and blood flow is diverted only to the heart, lungs and brain. Sea mammals are believed to use this reflex to remain conscious during prolonged, deep dives. This reflex is seen most often in children and could diminish with age. Hypothermia, when the body cools at a slower rate, also may prolong the life of a drowning victim. Here, the heart stops and blood pools in the organs to keep them oxygenated.

The other factor is changes in recovery/rescue methods. There is relatively new and inexpensive sonar technology that speeds object location. There also is a fairly old method of dragging that recently has been packaged for sale.

Joseph Pung, a retired deputy sheriff from Chisago County, Minn., and Brad Schultz, a retired conservation officer with Minnesota's Department of Natural Resources, have spent a long time recovering bodies together. Both retired with about 30 years of body-recovery experience; Pung recovered more than 75 bodies in that time and Schultz recovered almost as many. Several years ago, Schultz and Pung worked with Minnesota's DNR to create an instructional video on how to find drowning victims using their system.

Pung and Schultz modified a drag system designed by a former Chisago County Sheriff's Office recovery expert, who was also a diver. Pung and Schultz are calling the system the Chisago Method of Victim Recovery. It uses five small boats tethered together, with the middle boat serving as the lead. The lead boat has three team members; the other boats each have two. Pung and Schultz recommend having a sixth boat to serve as a support vehicle and control water traffic.

The drag bar is a H-inch steel triangle with 4-foot-long sides and a support bar running from the apex to the middle of the bottom bar. A rope is attached to the top and six chains are secured at intervals across the base. Each chain has a four-prong, 2H-inch treble hook. The hooks are held to the chain by a medium-weight S-hook designed to pull apart if the drag hook gets hung up on something heavy like a boulder or a fallen tree. The system is being sold for about $1,500 by GearGrid, a Forest Lake, Minn.,-based company known for its firefighter storage lockers. Schultz and Pung say they have no financial interest in the system.

It takes one 50-hp engine on the lead boat to pull the other boats; a smaller engine on an outside boat will make turning easier. The boats back troll because it is easier to control the boats and drag off the front. They drag in a grid pattern across the water starting at the most likely place the victim went under. This system can cover a 300-square-foot area in four hours.

But dragging isn't typically the first method agencies try when it comes to recovery or rescue — diving is almost always the first choice. Pung and Schultz say the Chisago Method is the fastest, cheapest and most effective way to recover a body and that their track record of recovering bodies compared with dive teams speaks for itself. They also say that an experienced leader can train volunteers in minutes.

Schultz and Pung also say that they've never had a body disfigured by the drag hooks. The hooks usually catch on some clothing. If the body has little or no clothing, the hook will seat in the flesh. “If they were alive (and conscious), it is going to hurt,” Schultz says. “But this hook is not going to bury that deep in the skin; it is not going to tear.”

Diving expert Steve Orusa is a deputy chief with the Waukegan (Ill.) Fire Department. He joined the fire service in 1985 and began diving four years later. He's a regional dive team leader for Illinois' Lake and McHenry counties and director of the International Association for Dive Rescue Specialists Response Teams. In 2007, he authored a dive-rescue training book and he's appeared as an expert on CNN and MSNBC. He says he's been on more than 100 rescue or recovery dives in the United States and Canada.

Orusa admits that diving gear is expensive and training is time-consuming. His dive-rescue specialist basic equipment list contains 17 items ranging from a compass to a full face mask with electronic communications. It can cost thousands of dollars to outfit one diver, he says.

Underwater, it is nearly impossible for divers to see, especially in the Midwest, he says. What little visibility divers may have usually is erased by the sediment they kick up from the river or lake bottom. They essentially find targets by feel.

Despite these hardships, Orusa remains a proponent of diving and says dragging should be used as a last resort. “Drag hooks were OK years ago,” he says. “But technology and well-trained divers offer a better solution in most instances.”

He says the most effective method is using one boat equipped with side-imaging sonar and an underwater video camera, one diver, one boat operator, and one sonar technician. Once the dive team is on the scene, it should only take minutes to get suited up and in the water.

Orusa says that side-scan and sector-scan sonar units sell for about $40,000; the side-imaging sonar made by Hummingbird sells for less than $2,000. It is, he says, little more than an advanced fish finder. Underwater video cameras sell for about $1,000.

When the sonar locates an image, the camera is dropped to confirm that it is the target. The camera can see better in low-visibility water because it needs less light than the human eye. When the camera confirms the sonar's image, a diver goes down to feel around for the person.

Like the lead person on the drag team, a good sonar technician is critical, Orusa says. An experienced technician can distinguish false images, such as tree limbs, from bodies.

Schultz says that once his boats are on the scene, it takes 30 minutes to start dragging. He says that he's never seen a dive team get in the water in less than two hours.

“The biggest opposition to this system is that it is hard work and it is not glamorous,” Schultz says. “It is not techie. You cannot play with a gadget. There's no way to sweeten up hanging onto a rope and dragging.”

The one gadget Schultz and Pung have added is GPS, to make sure they are covering the entire grid they've laid out for dragging. They still use buoys as visual markers. “We're not adverse to different things,” Pung says, “even side-scan sonar. But it is so horrifically expensive.”

While a waiting family's burden is eased by a speedy recovery, fast action is paramount because a person may still be alive. Pung says they once recovered a small boy who was barely alive and later died. He believes that if his drag team had not been forced to sit on the sidelines waiting for divers to finish their failed search, he could have saved the boy.

Orusa says the Chisago Method may function better than divers if the dive team is under-trained or under-equipped.

But something all three agree on is the value of knowing what happens to a drowning victim's body and how witnesses behave. Most importantly, they say a search's success depends largely on how accurate the witnesses are in identifying where the victim was last seen above water.

Whether dragging or diving, the first step is making a quality size-up. And that size-up can change dramatically as the operation unfolds.

Jerry Smith is a game warden in Nevada who participated in a recovery operation this spring. Two men were fishing on a reservoir when their canoe capsized. The two men swam for shore; when the survivor reached shore and looked back, his friend was gone.

They spent days using sonar and dive teams and dragging with a grappling hook, Smith says. Smith knew of the Chisago Method and ordered the drag set. They practiced with it for a few hours, then found the body after one hour's search, he says. However, they found the body 75 yards away from where they had been searching. That's because the survivor gave better information once the shock and excitement began to subside, Smith says.

“Good dive teams … use scene evaluation and their clipboards or dry boards are their most valuable tool,” Orusa says. “I'm not going to put a diver in the water until I've done a scene evaluation and identified the last-seen point. Otherwise, you are wasting a diver's air and energy.”

This is because, except for very strong river currents, bodies fall to the bottom in an almost straight line from where they went under. And once on the bottom, they nearly always stay put.

Pung, Schultz and Orusa say it is critical to keep witnesses separated to prevent one's account of the incident from influencing that of the others. And as the case in Nevada shows, it is important to re-evaluate the scene constantly.

“If you don't have a decent location,” Schultz says, “you may as well go out and drive around with side-scan sonar.”