Archive for December, 2005

Underwater Exposures

Exposure settings for underwater photography depend on so many variable factors that it is hardly possible to make specific recommendations that will be generally useful. Among other considerations, the exposures in any situation will depend on weather conditions, the angle of the sun, the clarity of the water, the distance of the subject below the surface, and the color of the bottom. One do-it-yourself way to determine exposures is to seal a light meter in a waterproof jar and take it under for a reading; and there are a number of special “underwater” light meters, and housings are available for most standard light meters. As is so frequently the case in specialized applications of photography, it will be necessary to experiment to determine the best exposure settings for black-and-white and color films.

Underwater color photography presents a number of complex problems caused by the selective absorption and selective scattering of the different colors of light by water. The details will vary for different localities and for various water conditions, but in general red and blue wave lengths tend to be absorbed, so that the light that penetrates to any distance below the surface tends to be decidedly greenish.

Filters

Although daylight does penetrate water to a considerable depth, color absorption and scattering make effective use of natural light limited to the period between midmorning and early afternoon. For depths below 6 feet, it is usually helpful to use a filter to counteract the greenish tinge imparted by water.

For black-and-white film, a medium contrast filter generally gives better results. The Wratten is satisfactory for most waters and has about a 2-time factor or one stop when used with panchromatic black-and-white film. Excessive blues and greens have to be held back to allow reds, browns and yellows to receive their proper share in the color balance. With a filter, the maximum camera range through water is about 40 feet. The greater the distance through water, the more filtering is required, resulting in a denser filter to compensate. At present it appears that until faster color film is available, distances greater than approximately 40 feet through water are impractical to filter. The important fact to have in mind for using underwater color filters is the light distance through water. This involves both distance and depth. For example, if your depth is 5 feet and your object is 15 feet from the camera, your light distance through water is 20 feet.

An underwater color filter with a factor of approximately 2 times or one stop is effective up to about 20 feet through water. One with a factor of approximately 4 times, or 2 stops, is effective from about 20 feet to 40 feet. Those factors cover daylight-type color film. Distances beyond 40 feet will be aided considerably by the use of a filter, if light is sufficient to bring them in. It has been found that results are better if the background of the underwater picture is held to within 40 feet. In underwater photography it is important to “background” your photographs. Better results will be obtained if the subject is “shot” against coral or other background within the effective camera range. Do not shoot into a water mass.

Underwater filters are made of plastic and are moderately

Scuba equipment and the plastic-encased underwater camera have opened new vistas for amateur and professional photographers.

stable, but should be kept out of direct sunlight and covered when not in use. The filters can be used on underwater cameras with filter mounts on the outside. Wash them with fresh water after using. They are susceptible to scratches, but small scratches will not interfere when used under water on the outside of a camera case.

In discussing filters, it is necessary to speak in approximations in some cases. The use of filters under water (the same as in air) will vary with surrounding conditions. Under water, they are: turbidity, sunlight and clouds, and particularly the color of the water. The judgment gained by experience will be of value in selecting filters as well as other photographic settings.

For the ultratechnical expert, the underwater filter should be changed to a small degree according to the water color found in each location each day, and possibly each hour. However, for general use the filters described above should satisfactorily cover the greatest number of underwater situations.

This is why one important fact of water skiing is that using hand signals do work and make the ride a lot safer.  Using hand signals between the driver and the skier is one of the most important things to remember about water skiing. 
 
The size of the area needed for water skiing safety will vary with the shape of the body of water.  Each boat using a water way for skiing should operate in a corridor about two hundred feet wide. 
 
The boat driver is responsible for keeping the skier away from dangerous areas as well as giving him a good ride.  He must also keep the boat a safe distance from the shore, docks, and other objects in the water.  Be on the look out for other boats about to enter the ski area.  If this would happen, shut down the boat and wait for the area to clear.  This is an important fact because it is the boat driver s responsibility to be on the watch for downed skiers. 
 
Remember to always stay in control.  Being safe means making good judgments and remember that any vibration or effects of sun, wind, and waves can impair your judgment.  And do not stay on the water too long. 

WITH almost three quarters of a million Americans finding their favorite pastime in underwater diving and marine exploration, there has been a tremendous increase in underwater photography as a hobby. Several years ago underwater photography was limited to the rather tame technique of taking photographs through the glass-bottomed boats that were features of some resort areas. Today both skin and scuba divers have found that modern underwater camera equipment has added a new element to their sport.

Deep diving has a peculiar psychological effect the deeper a diver descends, the poorer his powers of observation become, and an image on photographic film is one definite way of recording what he has seen.

The problems of underwater photography were first approached on a large scale by professional motion-picture producers who found considerable public interest in scenes shot beneath the surface of the water. The use of cumbersome diving bells proved both expensive and inefficient and it became necessary to develop truly portable photographic equipment. The first attempts were along the lines of “breathing” equipment, which automatically maintained within the camera housing a pressure slightly higher than the surrounding pressure. In turn this called for pressure regulators and exhaust valves, in order to equalize the pressure at different depths. Later developments, however, made this type of equipment obsolete, and a more modern approach led to the manufacture of pressure-resistant housings with the controls working through self-sealing gaskets. Paralleling the Hollywood work on underwater photography, much research in this field has been done by the United States Navy, although much of the Navy’s research has been kept in the “classified” category and has not been made available to the public.

The basic problem of “housing” camera equipment has been approached in several ways. The most simple consists of a flexible plastic bag with about a 6-inch plastic window. For use with most 35mm or simple brownie-type cameras this has been found effective in shallow depths down to about 10 or 15 feet. Controls are manipulated through the sides of the bag.

There are a large number of special “underwater” cameras on the market, ranging in price upwards from $19.95. In addition, underwater housings are available for most popular types of still and motion-picture cameras, in metal-usually cast aluminum-or plastic, generally plexiglass.

Metal housing is usually suggested for divers planning deep work, or those whose equipment will take much abuse. The plastic housing is most often a custom-made job. It allows viewing of all settings on the camera, and more controls can be set in a plastic housing than in most metal ones. Generally plastic housings are tested for depths down to 60 feet, metal housings to about 150 feet. The housings can be built for negative, positive, or neutral buoyancy in water, although many underwater photographers have found that a slight negative buoyancy is more practical. It is somewhat easier to recover a dropped camera that is sinking than one that is drifting upward.

Even subminiature fans have been considered, and there are underwater housings available for Minox-type cameras. The recent development of electric-eye cameras has made the task of underwater photography easier, and both electric-eye still and motion-picture underwater equipment is available. Electric-eye cameras require a shutter-release control, and if they are not electrically driven, also a wind control. It has been found, in practice, that the automatic-aperture control works effectively under water, as a solution to the somewhat difficult exposure problem.

Spearfishing has become an international sport. Under the sanction of the American Amateur Athletic Association and similar groups in other countries, competitions leading to national and international championships are held. Teams of three men from local diving clubs are entered in area contests. The top teams advance through regional and national contests to determine the national champions. In the international meets, the top teams from competing countries meet for the world championships.

The use of breathing apparatus is not permitted in formal competition. The rules allow only wearing a snorkel, face mask, diving suit, flippers and weighted belt.

In recent years international competitions have been held in the Bahamas, Italy, Spain, France, Yugoslavia and Portugal.

Information on underwater hunting groups may be obtained from the Underwater Society of America, Post Office Box 724, Station “A,” Champaign, Illinois. The international governing body is the Conf d ration Mondiale des Activit s Subaquatiques (International Underwater Confederation) . Its membership includes the United States, West Germany, Belgium, Brazil, Spain, France, Great Britain, Greece, Malta, Holland, Italy, Monaco, Poland, Portugal, Austria, Morocco, Finland and the Soviet Union.

Conservation Work

An interesting offshoot of underwater hunting is the aid that skin and scuba divers have given to conservation. In several areas on New York’s Long Island, underwater hunters have been found to be the most efficient means of combating the starfish which devour beds of shellfish. Each year divers are called on to join in a mass attack on starfish. Scores of divers respond, tons of starfish are removed from the water, and prizes are awarded to the divers bringing up the largest numbers.

Hunting Lobsters

Hunting lobsters provides exciting underwater adventure. From Long Island, north through New England waters, the clawed “Maine” lobsters are found. However, their capture is closely regulated by law, and besides limitations on the minimum size that may be taken, most states require that they must be taken only in approved lobster traps or by hand; no weapons may be used. The fast-acting, powerful claws of the lobster make its capture somewhat difficult. More experienced divers approach a lobster from the front. The lobster’s characteristic defense pose is to stand on its tail waving both claws above its head. The object is to catch both claws before the creature has a chance to bite. The more timid lobster hunter can approach from the rear, and try to keep his hands out of the crustacean’s claws.

The lobster’s claws seem to detach from its body almost at will, and it readily sacrifices one claw to obtain a punishing grip with the other, which makes it somewhat of a problem to catch it among rocks or crevices where it often lies with only its claws showing.

Only the Maine lobsters have claws. The lobsters found in other and warmer waters are clawless, but protected with sharp spines pointing forward. Projecting feelers act like antennae, to detect any sign of danger, and the response is usually extremely fast-a quick retreat to a crevice or under a rock. Dislodging the lobster is difficult, since its spines give it a firm hold, and it may actually be pulled apart before its hold on the rocks can be broken. A nocturnal eater, the lobster is sometimes hunted under water at night with a waterproof light. In the open, it may be approached more easily, and while hunting its own food, may be somewhat less alert to a diver’s presence.

The Game Fish

In almost every section along the coasts of the United States the divers can find fish that are considered good game. In the northern section of the West Coast, the ling cod, which often reaches almost 40 pounds, and salmon are the prime quarry. Farther south along the California Coast, many undersea hunters go after the white sea bass which travel in schools and reach about 60 pounds; these fish range from a few feet below the surface to about 100 feet down.

In the Gulf of Mexico are found many great barracuda, Warsaw, cobia, and the jew fish or black sea bass which reaches some 600 pounds. The Florida Keys abound in game fish. On the East Coast, the sea bass, blackfish, mackerel and swordfish are desirable game. In all waters where they are found, the different varieties of sharks offer exciting hunting.

Sea-Turtle “Riding”

The giant sea turtle of tropical waters is another game that is caught by hand. Underwater, it can easily outswim any diver. The way to capture it is to come upon it when it is sleeping on the bottom; climb on its back, and “ride” it into shore or shallow water where it can be flipped over on its back; a position in which it is helpless. Turtles weighing several hundred pounds have been taken in this manner. Generally the turtle is clumsy and its bulk can be handled by a fairly strong diver. The danger, however, is from its powerful beak which can deliver an extremely damaging bite.

There are some facts about water skiing that everyone should remember and follow when on the water.  Water skiing can be a very fun and exciting sport, if you remember the facts about water skiing and stick to them. 
 
Nearly 17 million Americans water ski every year.  Very few of those people have never been seriously injured in a water skiing related accident during any season.  The death rate from such accidents is ten times less than the injury rate.  Water skiing is safe when skiers and boat drivers know and use common sense rules.  Be safe and be smart. 
 
A moderate ability to swim is advisable for a water skier, but be a great swimmer does not mean that you do not need a well fitting personal flotation device.  Wearing one of these vests is essential to a safe and fun ride. 
 
Water skiing is an adventure between the skier, the observer, and the boat driver.  The skier and driver should agree in advance on the general path of the boat.  A skier who turns in the same direction that the boat driver is about to turn the boat will get line slack that could result in a fall or getting tied up in the line. 
 

THE second step in the underwater progress of many skin and scuba divers is to take up the sport of underwater hunting. There is an almost infinite variety of game in coastal waters offering many choices of hunting for sea food or for the sheer sport of tracking and capturing sea game.

Any catalogue of underwater equipment offers a wide range of weapons from tridents and lances to rubber-powered and carbon-dioxide-propelled guns, different types of spring guns, slings and harpoons. Some have power heads which fire a cartridge on impact and shoot the barbed spear head through the prey. Some have a break-away feature with a detachable head fixed to a strong cable to absorb the force when a big fish makes his first rush. The exact type of weapon for any specific use depends on the kind of game, the underwater terrain, and the skills of the diver. Basically the underwater hunter’s weapons are analogous to those used by the gunner on land. The smaller, lighter-bored weapons for small game; the heavier equipment for the larger marine animals. Also, many kinds of underwater game can be caught by hand.

Basically, underwater hunting offers more of the thrill of stalking and landing the prey than does hunting on land. The underwater hunter must come very close to his quarry. The effective range of underwater weapons is extremely limited. Those which are not used at hand’s length seldom have an effective range of much more than 10 feet; and most underwater “shooting” is done at about 6 feet or less. But there is another difference between land and sea hunting. On land the gunner whose aim is successful has only to carry a carcass back to his camp or car. In undersea hunting, “shooting” the game is only the beginning of the hunt. After the quarry has been “shot” the diver must still hold it with a harpoon line, and may have to use ad-ditional harpoons to finish it. Very seldom will the first strike kill any large fish, and most will show surprising strength in trying to escape or even attack when they have been wounded.

Gathering Abalone

Perhaps the most widely known “hunting” activities of skin divers is the gathering of abalones, a large shellfish found only in the water off California and Mexico. Considered one of the delicacies of the sea, the abalone brings a high price in sea-food markets, and is a culinary reward to the diver who brings some up for his own table.
Unlike other common shellfish, the abalone has one shell; the other half of the creature (which is actually a member of the snail family) consists of a strong muscle which clings to its rocky home with great power. The “lore” of abalone divers has many tales of men being trapped under water when the abalone clamped down on a hand or foot, although it is hard to substantiate any of these tales. The tool for gathering abalone is a pry bar which is used to force the abalone free.

Many abalone hunters combine the search for the shellfish with hunting for more active game in the same terrain, as they are often found in kelp “forests” where game fish also congregate.

Flooding of a separate face mask

Learn to dive without a face mask. Then flooding of the separate face mask is not a serious problem. To clear the face mask use the following procedure:

1. Tilt the head backward.
2. Hold the upper part of the face mask tight against the forehead.
3. Exhale through the nose (another reason why it might be well to avoid use of the noseclip) . Water will drain past the lower edge of the face mask.

Also, exhale through the nose occasionally to clear the face mask of small amounts of water. This procedure will also prevent face squeeze by equalizing pressure inside the face mask.

Flooding of a full face mask

Flooding of a full face mask is a serious problem, but a well-designed scuba with a full face mask has a means of overcoming it. The technique depends on the type of apparatus used. You should have pool experience in handling this problem before undertaking any scuba dives.

Flooding of the breathing system

The seriousness of flooding of the breathing system depends on the type of scuba you are using. In general, it is less of a problem in open-circuit scuba than in the closed systems. You should, however, be alert to the possibility that the cause of flooding, a cut or torn-loose breathing tube, may prevent successful clearing of the system. Also, you should know how to clear the breathing system of your scuba.

Exhaustion of the air supply

Running out of air is not a very serious situation unless the air-reserve mechanism has failed to function. Even if this happens, the increase in breathing resistance as the air pressure drops should give you ample warning of this condition.

When the breathing resistance becomes noticeable, open the air-reserve valve and start the ascent. If opening the air-reserve valve does not restore normal breathing, make an emergency ascent. During ascent from any depth, the reduction in water pressure provides at least a small amount of additional air, unless the failure is mechanical. Continue to breathe normally throughout the ascent, if possible. If not, exhale continuously throughout.

Except in the most desperate situations, make an emergency ascent by swimming to the surface. The possibility of becoming entangled or of striking an obstruction makes it hazardous to use positive buoyancy for ascent. Swimming to the surface gives you a better chance to avoid entanglements and to clear any obstructions. Under some conditions a large object overhead may preclude anything but swimming.

An emergency situation can become so desperate that the need to surface outweighs the need for caution. If it becomes preferable to risk entanglement or injury rather than to remain where you are, inflate the life jacket and ascend with the aid of its positive buoyancy. Bear in mind that the ascent will be very rapid. The danger of air embolism increases, and the possibility of serious injury on striking an obstruction becomes great. Use positive buoyancy ascent only in order to resolve a life-or-death situation, and no other. Whatever the means of ascent, exhale continuously throughout.

At the surface

When you reach the surface assuming you have come up by swimming inflate the life jacket. Decide whether to take off the breathing apparatus or leave it on while swimming to safety.

Your scuba becomes very heavy when it breaks the surface and loses water buoyancy, and the harness may hamper body motion. If the breathing apparatus interferes with swimming, remove the equipment and tow it to safety. Before removing your face mask, consider the hazards of unfavorable surface conditions such as whitecaps or spray.

Wristwatch

A pressureproof, nonmagnetic wristwatch is essential for scuba use in computing time of dive, controlling rate of ascent and descent, and timing your underwater operations. However, most of the watches advertised as waterproof will not hold up under scuba-diving conditions; obtain one specially made for underwater use.

Wrist compass

A pressureproof magnetic wrist compass is necessary for underwater navigation. Although the compass can only give general directions, because of its inherent inaccuracies, it is a big help, especially under conditions of poor visibility. You may be able to find a naval-type wrist compass at an Army-Navy surplus store.

Flashlight

A flashlight can be useful in dark or murky water, although its effectiveness falls off as the amount of suspended

Safety-and in many areas local ordinances-require display of the diagonal-striped diver’s flag where scuba or skin divers are underwater.

sediment increases. While there are a number of underwater flashlights on the market, they should be used with some caution because of the inherent danger of hydrogen explosions that may result due to chemical action within the flashlight.

Life lines

The buddy line is a line 6 to 10 feet long. At night, or in poor visibility, each of the buddies secures one end of the line to himself. The float, line is a line long enough to reach from the desired depth to the surface. The diver should secure one end around his body-not his equipment- and have someone secure the other end to a float. As mentioned before, the float line may be marked with knots to indicate decompression stops. When diving from a boat use a surface line. This is a line long enough to reach from the boat to the point of operation. You should secure one end to your body, not to your equipment.

Noseclip

Some scuba divers find that a noseclip is helpful for equalizing pressure in the ears and sinuses. A properly adjusted noseclip is comfortable and does not interfere with pressurizing the separate face mask or with expelling water. It can be valuable for keeping the nose dry if the face mask is flooded or lost. However, you should be able to remove and replace the face mask under water without a noseclip, and a great many scuba divers do not use a noseclip at all.

Earplugs and goggles

The caution about earplugs is: never use them! They prevent pressure equalization of the outer ear and cause outer-ear squeeze. It is also possible that earplugs may drive through the eardrum and destroy the auditory bones in the middle ear. If you cannot expose your ears to pressure or water, do not dive!
Never use nonequalizing goggles. They prevent equalization of the eye sockets and cause eye squeeze.

Foot protection

If you will be using your scuba around coral, in shallow water, or on the beach, wear lightweight shoes (coral shoes if available) under the swim fins to protect your feet.

Handling Emergencies

Emergencies occasionally arise even though you have taken all sensible safety precautions. They may be caused by your failure to check some item in your equipment, or by some unforeseen or unavoidable development. You can almost always resolve the situation if you and your buddy stop to think. The real hazard in scuba emergencies is not what is happening, but acting on a blind impulse brought on by panic. Few situations in diving are so serious as to require instantaneous action. Remember your training. Do not panic. Above all, never abandon the breathing apparatus under water unless you cannot ascend without doing so.