Venomous Shells, Regulator Patents & SDM Collectors
by E.R. Cross
There is no substitute for the thrill and satisfaction of being a good diver, just as surely as there is no substitute for diving safety. Unfortunately, there is a tendency by some to take unwarranted risks in vain attempts to enhance some aspect of the dive. Some want to dive deeper, stay longer or dive under more forbidding environmental conditions than their qualifications allow. One of the reasons for this tendency is the nature of sport diving. The environment of the diver seems friendly;not necessarily free of risk but with manageable hazards. A euphoric feeling about diving often continues with the most advanced commercial diver.
In all watersports, including diving, certain inherent hazards exist. When divers go underwater they are entering an unnatural environment. To survive they must take a reliable source of air with them or be able to surface to obtain a fresh supply. The continued safety of a diver may depend on an ability to meet and quickly cope with existing or developing hazards. Diving knowledge, proper equipment and ability have confirmed that diving is a grand experience for all when safety rules are followed.
Standards have been established and adopted that set certain limits for all the many aspects of diving. Training programs for recreational divers set the depth of a dive at 130 feet. A time limit is also set so no decompression is required for a safe ascent. Divers certified for these limits are entry level. Diving under any deviation from the depth, time or environmental conditions may require additional training and certification. Those who wish additional information on any qualifications for special diving activity may write to E.R. Cross, c/o Technifacts, Skin Diver Magazine, 6420 Wilshire Boulevard, Los Angeles, CA 90048-5515.
Nancy, a student of shells in Hawaii, asked, How venomous are the stings of cone shells? Also, what other shells have stinging apparatus? Cone shells are equipped with a poison sac of loosely attached radula teeth. The teeth are hollow and sometimes have a sharp barb. Each tooth is connected to a venom gland. Single barbs are taken in the proboscis, not in the siphon canal, extended in front of the animal and injected into the prey. The stinging apparatus is used to inject poison into the prey to immobilize it while it is swallowed whole.
On two occasions I observed a large species of a cone shell (Conus textile) inject a fluid from its siphon into the water near a small fish. The fish began swimming erratically, but the cone was not able to make further contact and the fish ultimately swam away. The diet of a cone shell probably dictates the size of the poison system. The larger their prey, the larger their stinging apparatus and the more virulent their poison.
In obtaining food the cone shell extrudes one of the radula darts and impales its victim, which may be a small fish, various kinds of worms and other mollusks. The aperture of a cone shell is quite narrow and, to accommodate its victim, the cone shell may evert its stomach until the food is surrounded. It is then digested externally until it will pass through the aperture of the shell.
The stings of certain cones have been responsible for fatalities, paralysis and painful wounds in humans. Apparently, the size of the shell and species indicates the size of the radula system. Shells that have been identified with human injury, and in a few cases with death, include Conus textile, C. striatus, C. quercinus, C. sponsalis and C. catus. C. gloriamaris has a very large poison system and is probably a potentially hazardous animal to handle. All live cone shells should be handled with caution; never tuck them into swim or dive gear. Carry them in separate bags.
For more information on venomous cone shells and other poisonous mollusks (there are several others), write to E.R. Cross, c/o Technifacts, Skin Diver Magazine, 6420 Wilshire Boulevard, Los Angeles, CA 90048-5515.
Patent Restrictions on Dive Regulators
In recent months two readers, one from Australia and one from Texas, wrote with similar requests. Both were interested in the patent protection for the double and single hose regulators. Patent regulations and requirements are extremely complex. However, it appears the patented part of the double hose regulator was the idea of bringing the exhaled air back to the demand regulator. This reduces or nearly eliminates the differential in pressure between incoming and exhaled air, which is necessary to reduce breathing resistance. This produced the regulator used for many years by divers. No one could make and sell a double hose regulator without paying royalties to the holder of the patent rights and these fees increased the cost of the regulators.
The need to bring exhaled air back to the inhalation point is accomplished in a single hose regulator by placing both the inhalation and exhalation point in the combination mouthpiece/demand regulator. Initial objection to this idea was that exhalation bubbles passing in front of the divers mask would interfere with the view. Experienced divers who had used dive masks with a surface air supply knew from experience this was not a valid argument. The Sport Diver was the first single hose regulator marketed. It was manufactured and distributed by Divers Supply in Wilmington, California, in the early 1950s.
Concurrently, or within a year of the Sport Diver, a similar single hose scuba was manufactured and sold in Australia as the Dolphin. For personal reasons the developers of both units did not patent their dive regulators. Anyone could, therefore, manufacture and sell single hose dive gear. Some alleged improvements have been made on the regulators that have been granted patents. These include, but may not be limited to, downstream valve systems, tilt type demand control valves and probably others. The patented improvements cannot be used by anyone other than the patent holder. For safety, the Sport Diver system was designed with downstream valving systems. However, the basic idea of the single hose regulator can never be patented. It can be used by any manufacturer without paying royalties that will increase the cost of the most important piece of dive gear.
Skin Diver;the Premier Dive Magazine
Skin Diver is the most sought after publication by collectors of diving memorabilia. Frequently readers write asking for sources of back issues. One of the foremost collectors of dive magazines is Robert Finch, 3306 W. Raintree Drive, Tucson, AZ 85741-2967 USA. He wrote, As [an] historian of diving magazines, newspapers and news letters, I would like to correspond with other historians, collectors and past and present publishers of similar publications in Spain, Portugal, Japan, South Africa and other countries. I would like to compile a complete history of all diving periodicals, worldwide. Primarily Bob collects through trading. He has a significant collection of SDMs.
Another source for back issues of SDM and many other dive publications, is David Way, The Divers and Watersportmans Library, 10 Cedar Road, Preston, Paignton, Devon, TQ3 2DD England. A recent catalogue published by David includes a listing of 450 rare and hard to find books on all phases of diving. David wrote, The premier diving journal in the English language is Skin Diver. David buys and sells the publication but builds a large collection of SDMs through exchange. For a copy of his latest listing of books and magazines, send $1 U.S. to cover cost of postage; it will be refunded with the first order. David also lists wrecks, some unusual photographs, papers and reports of possible interest to SDM collectors.