Search and Recovery
by E.R. Cross
The search for and recovery of a lost object is usually a recreational divers first commercial venture. These enterprises are usually successful. They involve only a diver and his buddy. Most of the objects are small and light enough for divers to handle. After a successful search phase, recovery of heavier objects can be made by attaching a line to the object and hauling it into the boat or onto the shore.
A reader from Arizona wrote, My dive buddy and I do minor search and recovery in several lakes in Arizona. Recently, we found some heavy objects (boats). We now need a method for raising them to the surface.Our dive boat is a good, safe, dive platform but will not support any added weight.
Various types and sizes of commercial lifting gear are available. Mostly they are inflatable liftbags. Different designs and sizes are capable of lifting weights from a few pounds to a few tons. The liftbags are collapsible and easy to stow and handle. Different capacity bags have valving and venting systems compatible with the weight that will be handled.
Local recreational dive shops may not have liftbags in the size and lifting capacity needed by a dive team. For a wide range of liftbags, write to Dive Commercial International, 4315 11th Avenue, NW, Seattle, WA 98107-0667. DCI says it can supply most styles and sizes of liftbags.
Before commercial liftbags became available, divers made their own inflatable systems. The most common method was to convert 55 gallon (and smaller) steel drums or barrels into lifting devices. In the September 1980 Skin Diver Magazine, Technifacts (then called Scuba-Tech) featured a lengthy article on various aspects of commercial scuba diving. Included were sketches of the conversion of steel drums to lifting devices. In the September 1970 SDM there was a one page article on making a rubberized canvas liftbag that may have been the forerunner of todays commercial liftbags.
Divers should be aware that objects being salvaged, such as boats, engines of various kinds and most containers, may contain oil or other liquid pollutants. During lifting, their contents may spill. One pint of spilled oil may cause a slick equal to the size of two football fields. Such a slick can interfere with the developmental stages of several forms of plankton. Compared to global pollution problems this may appear minor, but the salvager will be held responsible.
Marine pollution is an ongoing global problem. The highest percentage of pollution is washed from the land into the streams, lakes and rivers that ultimately empty into the surrounding seas and oceans. Billions of drops of oil, dripping from millions of cars onto streets, highways and parking lots, eventually flow into the oceans. Research indicates that 180 million gallons of used oil from surreptitious engine oil changes are poured down storm drains. The report concluded, That is equal to 16 Valdez-type oil spills. The 1983 issue of The Times Atlas of the Oceans showed that 28 percent of oil pollution in the oceans is from land run-off; only 24 percent was from tanker operations, including spills. Nearly 75 percent of the ocean near landmasses showed intermittent serious pollution of some kind, including sewage, radioactive material, mine tailings and pulp waste (both sugar and coffee pulps are significant pollutants in some areas). In other areas, fertilizers, many kinds of industrial chemicals and, overwhelmingly, plastic wastes are the problems. Additional killers of marine life are monofilament line and nets.
Divers are unlikely to contribute to marine pollution while engaged in diving. After all, the world beneath the sea is our environment. We like our recreational areas clean and uncluttered. However, there are some kinds of dive or boating paraphernalia that can become either unsightly or potentially hazardous marine debris. Information in the September 1997 issue of Seawords, The Newsletter of the Marine Option Program, University of Hawaii, reports that turtles, cetaceans and many kinds of fish are susceptible to endangerment, either as a result of entanglement or ingestion of some kinds of marine trash. They also become entangled in the plastic retaining rings from beverage can six packs.
The unsightly pollution includes beverage cans, bottles, their cartons and plastic retaining rings. Rarely are smaller forms of marine life trapped or wedged in this form of trash. However, it does occasionally happen. Seldom will dive boats have hazardous nets on board. Nevertheless, proper disposal of even small nets and short lengths of monofilament line should be followed.
In a Seawords article, Alice Keesing reported some startling data. Ninety-nine percent of the 312 species of sea birds ingest plastic pellets, mistaking them for fish eggs. Some turtles feed on certain species of jellyfish. Plastic wrappers appear similar to the jellyfish and are also ingested. In a 1996 cleanup of marine trash, more than 20,000 pieces of plastic food bags and wrappers were gathered, as well as nearly 22,000 pieces of plastic foam;a potentially deadly harvest. In addition, 40,209 cigarette butts were recovered. Ive heard about second hand smoke; what about second hand tobacco?
The Future of Diving
The science of diving has remained constant for thousands of years. The physical laws of solids, fluids, gases and their interaction remain unaltered. Also, the understanding of diving physiology has remained static for many years. Rewriting proven ideas of the sciences and physiology of diving will not change age-old principles.
In recent months, much has been said about taking diving into the next century. It is important to note that the subject as discussed has been about getting diving into the next century and not through it. A century is 100 years, a very long time. A lot can happen in 100 years.
For many of us diving started early in the 20th century with Victor Berg, diving for pearls in the South Seas or with Jules Vernes Captain Nemo in the submarine Nautilus. In 1934, it was with some disappointment I met the real world of modern diving in the Navy: hand pumps and open bottom, shallow water helmets to depths of 60 feet. Usually, a dive was limited to less than one hour. With changes in dive gear and technology, and a much improved understanding of the science of diving, we got to the 21st century. Saturation diving is possible to depths of more than 2,000 feet. Duration of a dive might be 30 days with an additional six to seven days under decompression.
The millions of readers of Skin Diver Magazine are predominately into diving as a sport; a healthy, body building sport that is enjoyed by all. Some commercial divers are already into 21st century diving. Their equipment is complex, potentially life threatening and not user-friendly. Some of it is becoming available for very advanced recreational diving. However, this may not be a path recreational divers want to follow. Stay with Skin Diver Magazine for your enjoyable path to future diving. You will be glad you did.