Sources - The Journal of Underwater Education|
International publication of the National Association of Underwater Instructors (NAUI)
Lift Bags, Floats and Tubes, Divers Tools, and Surface markers
By John Christopher Fine, Naui 4431
Displaying a dive flag is mandatory. While the international white and blue "alpha" pennant is used and even in some circumstances required, the accepted diver down flag is red with a diagonal stripe from the mast to corner. By Florida regulations, water craft are required to keep 300 feet away from the diver down flag in open water areas and 100 feet away in congested canals or restricted waterways. Other states have similar laws.
As a kid I allways made my own dive flags. I found red plastic construction flags that had blown off truck and littered the highways. It required only tape and can of white spray paint o make my flag. I'd fix it to an inner tube, rig a line to the tube and tie a mesh bag in the center of the tube to hold stuff I'd find underwater.
This is still a great surface float and flag holder. I use it when I teach dive courses. Tired snorkelers and divers can hold onto the inner tube and rest, the mesh bag can hold stuff like extra masks or fins and the tube makes a good dive flag support. The flag's pole can be stuck through a wide strip of cut inner tube rubber or tied to the tube with line. It's basic, but functional.
I do a lot of diving in Florida's Gulf Stream. This current can whisk along at two knots or more at times, but even a half-knot current down below with a swifter surface current creates a lot of resistance, and thus the inner tube is not practical.
In drift diving, the current carries us along. It is not enough that a boat on the surface displays a flag. the boat operator must see the divers and stay within range to be able to pick them up after the dive or render aid if a diver surfaces with a problem.
In calm water with only one buddy team in the water, good ocean operators can keep their eye on dive bubbles that break the surface. But even in calm weather, it is easy to lose sight of divers' bubbles. In rough-ocean conditions created by wind or waves this technique is not practical. Divers must take a flag and float with them so the captain can keep track of where they are.
Styrofoam floats and float balls have been used with various reels or line holders. Polypropylene line that floats and is invariably yellow is often used with inexpensive floats.
floating line tends to tangle, so many divers prefer non-floating line that is strong enough to do the job.
Divers must be autonomous. The French called scuba divers "plongeurs en scaphandre autonome" autonomous diver not connected to the surface with are hoses or cable. Autonomy is important as is having the correct tools to cope with situations that occur underwater.
I have lost my dive flag underwater. I may have tied it off or used a hook while taking photographs, or I may have paused in my picture taking and became separated from a buddy who was the flag carrier. In some cases the flag separated from the surface float. In open water with potential danger from boat traffic on the surface an alternate float marker should be required equipment.
A lift bag can serve as a marker float as well as be used to send up a found weight belt, anchor, or other treasure and is a boon to divers. The buoyancy compensator should not be used as a lift bag. A diver inflating a BC to bring something to the surface risks heading up too fast and with hands occupied may not be able to vent air or in dumping too much air the diver can descent again rapidly with the heavy object.
Having a lift bag or personal float that can be used for multiple purposes is important. Thin, inexpensive, brightly colored sea tubes are often not sufficient in ocean diving to adequately mark a position or to support weight. I have seen sea tubes (sometimes called sausages) collapse, become impossible to inflate and to fail entirely.
Jim Carter of Emumclaw, Washington has designed a sturdy personal float that can serve as a surface signal equipped with its dive flag as well as a convenient lift bag. There are times when I use a motion picture camera underwater. One of my cameras weighs 39 pounds, thus the Carter personal float is my safety support in the event I want to send the camera up. Carter's lift bags re also convenient and will serve not only to send objects to the surface but with their conical shape they retain air and thus can be used to mark the diver's location below and support weight. Carter makes commercial lift bags that can lift six tons. Their commercial materials used on divers' personal floats and bags are just as sturdy and durable. There are important features that Carter lift bags provide such as handles and tie-off points. The-off points make it easy to rig underwater.
Lift bags designed to be rolled or folded into small, negatively buoyant, compact size are ideal for a diver. Bulky equipment that creates drag and is buoyant adds to the difficulty of a dive. A reflective strip adds a margin of safety for divers using them in darkness. Lights or light sticks can be affixed for night diving.
Divers learn that air delivered at ambient pressure form a dive regulator at depth will expand on the way to the surface. This is just as true when air is put into a lift bag or personal float underwater. When the bag inflates and heads up to the surface, the air expanes. Without an overpressure relief valve or an open bottom, the bag would burst and the object it supported would fall back to the bottom. BCs have these overpressure relief valves incorporated into them as well to prevent over-expansion on ascent.
While there are many uses for personal floats and lift bags, as safety markers on the surface as well as to bring objects up from below, there are techniques that must be used and safety precautions to be taken when using lift bags or floats underwater.
The personal float or lift bag should be unrolled and deployed carefully so that its line does ot tangle the diver. One buddy should remain clear in the event of entanglement ot remove the line from the other diver's gear if necessary. Unrolled, the float or lift bag should be secured to the object before any inflation is attempted. The object should be properly rigged so that there is no danger of it coming loose on the ascent and falling back down.
An alternate air supply should be used to inflate the bag. Air hoses are made for this purpose although most divers use their octopus to inflate the lift bag. Do not use your personal air supply regulator. make sure that as the bag r float inflates, the lines and bag will not catch in your equipment and the lift bag and object will rise free and away from you. Inflate the float or bag slowly at first. The float will take shape and rise in the water. Once the float or lift bag takes shape and rises in the water, remain clear. Then add sufficient air so that the object rises off the bottom. Do not try to fill the lift bag or float since the air will expand on the way to the surface. Do not stay underneath or on top of an inflating bag or float.
there come a time when expanding compressed air will cause the bag to head up to the surface quickly. You do not want to by caught by it, struck by it and thus pushed up, or hold onto it to be whisked up faster than your proper rate of ascent. Needless to say, if your rigging is not right and the object falls or if the lift bag fails, you do not want to be under the object and have it fall on you.
Using a personal float or lift bag as a surface marker, the same procedure occurs. The float or bag is unrolled from its compact pack. Care is used so that the lines do not tangle in the diver's equipment. Air is introduced into the opening of 3the bag. As it takes shape and begins to rise more checks are made to insure that there will be no entanglement. The bag is inflated to size using the diver's secondary air supply or octopus. The personal float or bag is sent to the surface. the line must be free to unreel. When the float is deployed, the diver is able to use the attached line to keep contact with the float. Underwater photographers often use the line to secure their heavy camera equipment while they do their decompression or safety stops.
Personal floats and lift bags have multiple purposes and uses. They are handy and convenient and with basic precautions are easy and safe to use. While every dive offers its own special treasure, certainly the occasional great find underwater can be recovered if the diver's float doubles as a lift bag.
Sources - Third Quarter 2006 copyright NAUI. All rights reserved.Back to Sources main page