Public Safety Buoyancy
Posted on: September 25, 2013
Photo Credit Keith Cormican
Public Safety divers spend a lot of time practicing search patterns, signals, evidence collection and team safety. Each one of these skills and techniques are very important part of a safe and successful mission. Have you ever thought about what each of these things have in common? What is required to perform these skill successfully? Buoyancy. A search pattern cannot be successful if divers are floating away. Signals cannot be transferred if they are not felt. Evidence is impossible to collect if it cannot be found due to silting. The team is not safe if they cannot control ascents and descents in the marine environment. When is the last time your team practiced buoyancy skills?
The search patterns, such as the Sweeping Arc, Jack Stay or Expanding Circle, all require refined buoyancy to make them effective. Consider a new public safety diver being deployed in any of those patterns and not taking a few seconds to establish proper buoyancy. During these patterns they are trying to use their hand to feel for an object in near zero visibility. Because of the lack of buoyancy their face is planting into the ground, their hand is being used to push off the bottom or they are floating away, out of reach of any potential object. Each time their body disturbs the sediment it makes it that much harder to locate the target.
Recreational divers are trained to stay off the bottom with visual references. They swim along looking for the fish and staying off the delicate plant life or structures. If they get too far off or start to float away, they check their computers and have ample time to adjust their equipment or techniques. Public Safety divers do not have those options. They know their target object is on the bottom, but they cannot see the target, let alone the bottom. They don’t know how far they are from the bottom unless they touch something. If they float above the bottom, they are lucky if they can clearly see their computer in time to realize their actual depth. The one thing they do not have is ample time to adjust for misjudgments. Their line is being pulled, the current is moving them or they are struggling their way through some aquatic obstruction.
The diver feels rushed to get into the water and complete their task. They have a lot of things on their mind and they may have some hesitation going into an unknown environment. If the diver is not trained to stop and obtain good buoyancy the mission could become more difficult or fail. Proper buoyancy requires controlled breathing, an understanding of their equipment and the ability to make adjustments using their senses since they may not have a visual reference.
The Public Safety diver never has a choice of where they want to dive. As much as the diver would like the mission to be in warm, clear, flat contour environments, we all know that is never the case. Buoyancy is a very important factor when the search pattern involves changing bottom topography. If the team decides on a circle search pattern and the pattern runs on a slope, the diver will continually change their depth and buoyancy characteristics. Just imagine a slight slope where the diver is at 10 feet during part of their pattern and 35 feet at the opposite end. If the diver does not have good buoyancy control there is an increased hazard for runaway ascents or dragging the bottom and possibly destroying evidence. Proper buoyancy will allow a diver to maintain neutrality no matter what depth during the pattern.
A buoyancy training technique you can try during your next drill involves a team of two divers. Have one primary diver place an obstruction in their mask which will limit their vision. Have the second diver act as the safety and lead diver. As the lead diver moves along in the training environment the primary diver follows by a slight touch to the lead diver as well as staying as close to the bottom as possible. The lead diver can intentionally rise above the bottom to the point the primary diver cannot touch. The primary diver will then need to adjust so they are touching the bottom again using only their fingertips. The lead diver can then re-establish contact and continue with the pattern. The lead diver intentionally moves up and down, away from the bottom, making the primary diver feel and adjust using their senses. The primary diver will need to know where the adjustment points are located on their equipment. They need to remain calm if they lose contact with the lead diver and maintain control of their breathing. The exercise will give the primary diver confidence in their buoyancy while being trained in a controlled environment.
A second training suggestion involves team members and extra weights, for an underwater game of hot potato. The divers all descend and establish neutral buoyancy with controlled breathing. The team brings down a bag of varied weights, from a few ounces to multiple pounds. When a diver gains good buoyancy, someone hands him a weight. The diver must re-establish their buoyancy with breathing techniques, BC adjustments or drysuit adjustments. Once they are neutral they hand the weight off to a nearby team member. As they hand over the weight, their buoyancy changes and they must re-adjust, only to be given a different weight. The exercise continues with the goal being the diver can quickly and properly adjust to changes in weight without overcompensating, or handing a weight off and not floating to the surface.
Dive teams need to become proficient with basic diver skills, such as buoyancy. All too often the team training focuses on the exciting parts of the mission and high end equipment and ignores refreshing on the basic skills. If the team works harder to become proficient at buoyancy, it will translate in to more efficient missions, safer divers and a greater likelihood of a successful mission.
About the author
Don Kinney – ERDI Instructor Trainer
Don Kinney has been a Public Safety Diver since 1991. He continues to lead his public safety team as well specialize in training other dive teams around the world. He has extensive experience in lakes, rivers, ponds, oceans and water holding tanks. He prides himself on developing training around the needs of each team and their unique environments. For further information please go to www.etds.org.
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