Saturday, June 30, 2012

Risk Factors for Dive Deaths

How older women differ from younger men in dive problems

Among divers, the three top risk factors for diving deaths are running out of air, buoyancy problems and rapid ascents - - and often times, these factors can happen concurrently. But what’s the biggest cause for those factors to happen - - the diver, his equipment or the overall dive environment?

To determine which has a greater impact, researchers Richard Vann, Petar Denoble and Richard Dunford of Divers Alert Network, along with Peter Buzzacott of the University of Western Australia, collected data via surveys taken by divers making dives from liveaboards, day boats and shore between 1995 and 2004 in the Caribbean, Grand Cayman and Scapa Flow. Overall, they collected data on 452,582 recreational dives with air or nitrox made by 5,046 adults. They published the results in the journal Diving and Hyperbaric Medicine.

The three problems - - air, buoyancy and ascent - - were classified as human (diver) or diving (environmental/ equipment) factors. Human factors included age, sex and certification level. Diving factors included dive time, maximum depth, air used, boat or shore dive, water temperatures and strenuousness of the dive.

Running out of air was reported by 65 divers (1.4%), 223 divers had buoyancy problems (4.7%) and 235 divers had rapid ascents (7%). Divers who reported running out of air at least once were slightly older than the average age of all divers (42) and more than twice as likely to be female. Divers with buoyancy problems were also likely to be female and slightly older, plus more likely to have just a basic diver certification. On the other hand, divers making rapid ascents were mostly male, slightly younger than the norm and more likely to have advanced certification or specialty training.

Based on diving factors, running out of air happened on slightly deeper, slightly shorter dives (averaging 22 feet for 45 minutes) from liveaboard or charter boats. Dives with buoyancy problems were more likely to have been made from boats, used air instead of nitrox, and were reported as strenuous. Rapid-ascent dives shared all the above factors, except they happened at shallower depths (an average of 21 feet).

So overall, older women ran out of air and reported buoyancy problems, while younger men had rapid ascents more often. It’s curious how the increase in certification status reduced the risk of buoyancy problems but increased the risk of rapid ascents. Researchers think it may be because divers are more attentive when diving deeper, or perhaps more carefree if they can see the surface when they start their final ascent.

The most interesting finding was that all three dive problems were associated with boat dives. The weak but significant association with shorter dive times is likely a consequence of being told when to return to the boat, but strenuous dives were strongly associated with all three dive problems. Perhaps divers are being taken to sites they later discover are more challenging than anticipated, especially older divers and women who, for example, may perceive a moderate current or long surface swim to be harder work than younger men do.

The high prevalence of divers ascending faster than a commonly recommended maximum rate (3.8 %) is cause for concern, especially as the majority of those who ascended too rapidly did not report it. It’s noteworthy that few people who reported a rapid ascent actually exceeded 60 feet per minute, and those who actually did rapid ascents later reported it on their survey as a problem. Of the 227 rapid-ascent dives recorded on dive computers, 88 percent were made by divers who were either unaware of their ascent rate, ascended rapidly during the dive at a time other than the final ascent, or may have defined rapid ascent differently from the researchers’ criteria. Therefore, at first glance, the prevalence of these problems happening appears relatively low. To put the findings into perspective, if this were an accurate estimate of the prevalence likely to be experienced by a dive boat taking 25 divers out for two dives a day for 200 days of each year, crew could expect divers to run out of air on 18 dives, 77 divers will report buoyancy problems, 63 divers will report rapid ascents and 49 dives will show a recorded rapid ascent on the computer. That makes a total of 201 problems per year, or an average of one event per dive day. So even a low prevalence as reported here should be cause for concern aboard dive boats of all sizes.

Therefore, dive instructors should give greater emphasis during basic training to monitoring gas reserves, effective buoyancy control techniques and the importance of ascending slowly, coupled with practical methods of gauging ascent rate (like monitoring depth-per-minute rather than looking up to the surface). Also, greater emphasis upon ascent rates during training should be used to reduce ascent speeds among future divers. And dive crew should advise divers before each dive to consider the potential for physical stress.


Kathy Dowsett

Wednesday, June 27, 2012

Responsible Reef Practices While Snorkelling

Practices that you can do to help sustain the Great Barrier Reef for generations to come

• Practice at first over sand patches and away from the coral:
• Get comfortable with buoyancy control and finning techniques.
• Be mindful of where your fins are to avoid accidentally hitting the reef or stirring up sand.
Snorkel carefully near the Reef:
• Move slowly and deliberately in the water, relax and take your time – to remain horizontal in the water, and refrain from standing up.
• Do not snorkel into areas where the water is less than one metre deep.
• Do not touch the walls of semi-confined areas (for example, small swim throughs and overhangs), never squeeze through a small area.
• Use rest stations or other flotation aids (for example, float lines, swimming noodles, and flotation vests) if you need to rest while snorkelling.
• Do not lean on, hold onto, or touch any part of the reef or moving animals when taking underwater photographs.
• Be mindful of all marine life:
• Avoid making sudden or loud noises underwater.
• Avoid chasing or attempting to ride or grab free-swimming animals (such as turtles, whales, and sea snakes). Avoid blocking their path or making them change direction.
• Do not touching or relocating any animals or plants.
• Stay more than one metre away from giant clams.
• Do not feed the fish.
• Do not collect any shells or ‘souvenirs’.

Thanks to New Horizon

Kathy Dowsett

Monday, June 25, 2012

What's the Total Value of the World's Sunken Treasure?

Three historic shipwrecks have been in the spotlight recently, with cargoes of platinum ingots, gold, and silver estimated at $4.5 billion in total. These huge hauls made us wonder: Just how much money is buried at sea?

When the last responders leave the sunken cruise liner Costa Concordia, the wreck's status may shift from grave site to treasure trove. Its passengers and interior decorators reportedly left behind a wealth of cash, jewels, antiques, and thousands of pieces of art. Souvenir hunters, looters, and even the mafia may have plans to dive the wreck for a piece of that fortune.

It's been a busy month for shipwreck headlines and shipwreck hunters. The team that announced the discovery of the Port Nicholson, a World War II–era British merchant ship found 50 miles off the coast of Maine, says it bore 71 tons of platinum ingots worth about $3 billion. Other shipwreck hunters turned up the HMS Victory, which sank in the English Channel in 1744 with a "secret" cargo of gold valued at $1 billion. And, in an episode that shows the high stakes of shipwreck salvaging, Spain is currently recovering the estimated $500 million haul of gold and silver from the Spanish galleon Nuestra Señora de las Mercedes that sank in 1804; an American company found the ship but lost court cases to Spain over the rights to the treasure.

All this undersea treasure hunting got us wondering: Just how much money is out there buried at sea? We put the question to marine archeologists, a historian, and a shipwreck hunter. Their answers ranged from "Who knows?" to "$60 billion"—and each was instructive.

How Many Shipwrecks are There?

An estimate of the value of sunken treasure in the world begins with a guess at the number of sunken ships. James Delgado, director of the Maritime Heritage Program at the National Oceanic and Atmospheric Administration (NOAA), estimates that there are a million shipwrecks underwater now.

"Given everything that's charted and all the rest, I would say that the majority of them remain undiscovered," Delgado says. After all, 70 percent of the planet's surface is water, and humans have only begun to be able to reach the depths. "[Considering] this, 95 percent of the ocean still remains unknown to us. It's the last frontier," Delgado says. "We know more about the surface of the moon than what's at the bottom of the sea."

Maritime historian Amy Mitchell-Cook at the University of West Florida says she doesn't think it's possible to make an estimate. "Even in Pensacola Bay, where I am, I don't think we have an accurate number of shipwrecks," she says. "There were Spanish, French, English, and Americans all in the area, as well as international trade. We know a lot of ships sank, but we don't have a complete set of records."

How Much Treasure is Down There?

The short answer, Sean Fisher says, is $60 billion. Fisher is a shipwreck hunter at Mel Fisher's Treasures in Key West (Sean is Mel's grandson), and he gives this figure based on his company's historical research. Fisher specializes in finding Spanish vessels that sank while toting gold, silver, and other loot from the Americas to Europe. And the Spaniards, Fisher says, kept records in triplicate, allowing modern-day shipwreck hunters to see the preserved ship manifests. Those manifests reveal an incredible amount of wealth crossing the ocean, and occasionally sinking into it.

"For about 300 years, the Spaniards came over here and stole all of the wealth of the Americas," Fisher says. "They would lose about 10 percent of that as the cost of doing business. Several wrecks out there by themselves are worth several billion dollars."

Thanks to Popular Mechanics

Kathy Dowsett

Sunday, June 24, 2012

Pygmy seahorse

Pygmy seahorse

The pygmy seahorse (Hippocampus bargibanti) is undoubtedly one of the most well camouflaged species in the oceans, being extremely difficult to spot amongst the gorgonian coral it inhabits.

So effective is this camouflage that the species wasn’t actually discovered until its host gorgonian was being examined in a lab. Large, bulbous tubercles cover this species’ body and match the colour and shape of the polyps of its host species of gorgonian coral, while its body matches the gorgonian stem. Two colour morphs exist: pale grey or purple individuals scattered with pink or red tubercles are found on the similarly coloured gorgonian coral Muricella plectana, and yellow individuals with orange tubercles are found on gorgonian coral Muricella paraplectana.

It is not known whether individuals can change colour if they change hosts, although the ability to change colour according to their surroundings does exist in some other seahorse species, such as H. whitei. Other distinctive pygmy seahorse characteristics include a fleshy head and body, a very short snout, and a long, prehensile tail. This is also one of the smallest seahorse species in the world, typically measuring less than 2 centimetres in height. The male carries eggs and young concealed within the trunk region.

Thanks to AKARlive

Kathy Dowsett

Thursday, June 21, 2012

Why You Might Remove Your Regulator When You Shouldn’t

Thanks to Undercurrents

Many divers trying to save a buddy from drowning report afterwards that, against all reason, their buddies removed their regulators from their mouths while they struggled for air. Over the years, Undercurrent has reported on many drowning deaths in which divers are found on the bottom with their second stages hanging free, but plenty of air still in their tanks. In one article, we reported that many firefighters breathing from air tanks have been found dead in the aftermath, with their regulators no longer in their mouths.

Recently, I came across the book Deep Survival by Laurence Gonzalez, in which he reports on research by Ephimia Morphew, a psychologist and founder of the Society for Human Performance in Extreme Environments. Gonzalez writes that she has "studied a series of accidents in which scuba divers were found dead with air in their tanks and perfectly functional regulators. 'Only they had pulled the regulators out of their mouths and drowned. It took a long time for researchers to figure out what was going on.' It appears that certain people suffer an internal feeling of suffocation when their mouths are covered. That led to an overpowering impulse to uncover the mouth and nose.

"The victims had followed an emotional response that was in general a good one for the organism, to get air. But it was the wrong response under the special, non-natural, circumstances of scuba diving. It's possible that the impulse, the feeling of suffocation, was formed as an implicit memory by some previous experience that was not available to conscious (explicit) memory. And the divers had no way of knowing that the one thing that would keep them alive, covering the nose and mouth, was the one thing the organism would not tolerate. At the critical moment of decision, reason was not enough to overcome emotion. For no one would say that those divers believed they could breathe under water without a regulator.

"Morphew and the other researchers wanted to know what divers were thinking when they removed their regulators and tried to breathe without them. The answer is: you don't need to think. That's what emotions and implicit memories are all about. By tradition, reason is regarded as the highest function. But from the point of view of an organism in desperate trouble, an organism that evolved by relying on emotions as the first line of defense, cognition is irrelevant and gets set aside. It's slow and clunky. As Remarque said, there's no time for it.

"Most of the mystifying accidents that happen in the course of risky recreation, the seemingly illogical decisions, actions, and outcomes, can be explained by the same interplay of emotions and cognition that shapes all human behavior. What the scuba divers did made perfect sense from the point of view of the organism's survival: The impulse to get air is automatic, and can be overpoweringly strong. Those who can control that impulse to survive, live. Those who can't, die. And that's the simplest way to explain survival."

As for the dead divers, says Gonzalez, "If you had magically transported them to the surface a moment before they removed their regulator and asked them about their impulse, they would have told you that it made no sense: The regulator was necessary for their survival. If you were able to ask them afterward, they would tell you that they didn't intend to take it out. They intended to live."

Kathy Dowsett

Wednesday, June 20, 2012

Sea Urchins- Some Sea Urchins Have Venomous Spines

Thanks Natalie for this story

Sea Urchins- Some Sea Urchins Have Venomous Spines:

Don’t worry, a rabid sea urchin is not going to leap off the reef and fling spines at you. Sea urchins are non-aggressive and relatively slow-moving. Still, sea urchin injuries are not unusual. Divers can easily become distracted and brush against one of these delicate creatures.

Sea Urchins Are Everywhere:

Sea urchin injuries are common because sea urchins are common. Divers encounter sea urchins in almost every body of salt water, including all of the world’s oceans. Rocky shores and shallow, sandy areas are some of the sea urchin’s favorite habitats. Shore divers need to take care to avoid steeping on urchins when wading shallow water.

Sea urchins are also found on coral reefs. Urchins hide in the reef’s crevices during the daytime. At night, they wander out to feed on floating food particles and algae. While divers can occasionally find sea urchins during the day, night divers in particular should be careful not to accidentally touch urchins which are more exposed in the nighttime.

Sea Urchins Have Two Defense Mechanisms:

Like most aquatic life injuries, sea urchin injuries are caused by the animal trying to defend itself. A sea urchin’s spines are its first line of defense. The length and sharpness of an urchin’s spines vary from species to species. Some species have stubby, blunt spines, while other species have long, sharp, venom-filled spines. Razor sharp spines can easily pierce even a thick wetsuit and lodge deep in a diver’s skin.

Many urchin species, such as the purple sea urchin, have an additional defense mechanism called the pedicellarines. The pedicellarines are tiny, jaw-like structures that can clasp onto a diver’s skin and inject a painful poison. The pedicellarines are nestled down between the urchin’s spines, and are difficult for a diver to contact unless he has already impaled himself on the urchin’s spines.

In extreme cases, such as numerous puncture wounds, the relatively small amount of venom from spines and pedicellarines can accumulate to cause severe muscle spasms, faintness, difficulty breathing, and death.

Sea Urchin Stings Are Avoidable

The best way for divers to avoid touching sea urchins is to maintain good awareness of their surroundings. Divers should control their buoyancy to stay at least a few feet from coral, which may conceal urchins in its crevices. Divers should also watch out for protruding spines in the sand, as many sea urchins bury themselves. Sea urchin stings frequently happen when a diver becomes distracted (e.g. chases a turtle for a photo) and inadvertently touches an urchin.

Sometimes, conditions make it hard to see urchins to avoid touching them. One example would be a rough shore entry though waves. Thick-soles diving booties, gloves, and thick wetsuits may provide some level of protection. However, long and sharp spines may still be able to pierce thick neoprene. If a shore entry has many urchins, pick a different dive site.

First Aid for Sea Urchin Stings

Urinating on a sea urchin sting will not help, so save yourself the embarrassment. As there are two sources of injury from sea urchins, the spines and the poisonous pedicellarines, both need to be dealt with.

Spines: A sea urchin’s spines can inject painful venom. Soaking the area in hot water (110-130˚F) for up to an hour and a half can break down the venom and help to alleviate the pain. Spines need to be removed carefully with tweezers. Fragile spines may be crushed or broken while under the skin. If a spine can not be easily removed, is near a joint, or is close to delicate nerves and blood vessels in the hands or feet, it is best to have it surgically removed by a doctor. Dark colored spines dye the skin so that it appears that a spine remains. This coloration should disappear within 2 days, if not, see a doctor to remove the spine.

Pedicellarines: Urchin's pedicellarines (the poisonous clasping mechanisms hidden between some urchin’s spines) can be removed by shaving the area with shaving cream and a razor.

After the removal of spines and pedicellarines, the injured area should be washed with soap and rinsed with fresh water. Topical antibiotic creams may be applied, and analgesics can be taken for the pain.

As with any aquatic life injury, patients should be monitored for signs of infections or allergies, such as chest pain or difficulty breathing. A doctor should be contacted immediately if either is observed.

Kathy Dowsett

Monday, June 18, 2012

Scuba Diving Lessons for Life: Is Getting a Catch Worth Your Life?

Thanks Eric Douglas from Scuba Diving

Offshore oil rigs serve as way stations for big fish, which stop and hang out around the massive structures. Roy and his buddies knew this and made regular trips to nearby oil rigs to go spear fishing. It was the best local opportunity to find game fish, and they always brought home dinner.

On the first dive of the trip, Roy speared a large goliath grouper near the rig. As he began bringing it toward the surface, the 200-pound fish started to swim away, pulling Roy along for the ride.

The Divers

As a dive instructor, Roy spent hours in the water helping new divers learn the basics. He often said the feeling of watching new divers’ eyes light up when they took their first breaths underwater was priceless. He trained upwards of 100 new divers each year, guiding them through each of their open water checkout dives.

One thing that Roy loved just as much as teaching new divers was spear fishing. Every couple of weeks, Roy and his buddies would schedule a dive trip without any students. They always headed to one of the nearby oil rigs and brought their spear guns along. Once they arrived home, they’d enjoy grilling that day’s catch.

The Dive

When Roy turned on his air just before getting in the water, his hrefa moment. He slapped it against his hand and reset the diaphragm. Roy commented to his buddy that he needed to get it serviced, but he had been diving so much he hadn’t had the time.

With the reg fixed, he did his giant stride and immediately descended down one leg of the oil rig. The visibility was typical for the location — they could see 30 to 40 feet in any direction, but beyond that, the open ocean was murky.

Many of the bigger fish they wanted to hunt stayed deep. When they approached 130 feet, Roy indicated he wanted to go deeper. His buddy signaled that he planned to level off and hunt there. Roy signaled OK and kept descending.

The Accident

Roy couldn’t believe his eyes when he saw the size of the grouper hovering near one of the oil rig’s legs. He estimated it weighed 200 pounds or more. He quickly prepared his spear gun and moved into position. Taking careful aim, Roy shot the large fish through the side. He reeled in the cable connecting the spear to his gun and began ascending. Roy could feel the weight of the fish below him, so he focused harder on swimming toward the surface. As he passed 130 feet, Roy paused for a moment to signal to his buddy that he was taking his catch to the boat.

On the way to the surface the grouper woke up, but Roy didn’t notice at first. With a jerk, the fish suddenly attempted to escape, only to come to a stop when it reached the end of the cable Roy had looped around a D-ring on his BC. The surge pulled Roy to the side as the line snapped taut. He grabbed the cable and attempted to continue ascending, but the grouper took off again — this time, the fish pulled Roy toward the surface. As they ascended together, Roy hit his head on one of the oil rig’s cross beams. Dazed by the collision with the cross beam, Roy found himself struggling at the surface.

A diver already on the surface reported seeing Roy wave his arm over his head to signal that he needed help. As Roy appeared to lose consciousness, the boat driver started the boat engines to get to Roy as quickly as he could. Roy sank below the surface of the water before help could arrive. Roy’s buddy and another diver spent nearly 30 minutes searching for and recovering his body.


Back onboard the boat, Roy’s buddies attempted to resuscitate him, but he was pronounced dead at a local hospital. When they found Roy’s body, his scuba cylinder was empty, his weights were in place and the grouper was still attached to the cable attached to his BC . Though Roy’s regulator showed signs of poor maintenance, this was not considered to be a cause of the accident.

The medical examiner determined that Roy had suffered trauma to his head after striking the leg of the oil rig, and this was a contributing factor in his loss of control on ascent; this, in turn, led to an air embolism that caused him to lose consciousness and drown.

Roy was in trouble the moment he speared the large grouper. In his mid-40s, Roy was of average size; the fish weighed as much as he did. Even if it had been killed instantly, Roy would have struggled to drag his prize to the surface. At the very least, Roy should have asked his buddy to help him get it to the surface. Better still, he could have attached the fish to a lift bag, inflated it and sent it to the surface, allowing him to ascend slowly and easily without struggling. When the stunned fish attempted to swim away, Roy was immediately in danger. With the huge fish attached to a cable fastened to his BC, Roy had to go where the fish wanted. At this point, he should have let go of the speared grouper.

Roy most likely wasn’t thinking clearly when he surfaced. He was probably dazed and suffering symptoms from the embolism. If he had dropped his weights and let go of the speared grouper, Roy might have survived the incident. He would have needed treatment in a recompression chamber, but he probably would have lived.

While it wasn’t a factor on this dive, Roy’s equipment was not well maintained and he was not properly equipped for a dive to nearly 200 feet. A diver depletes a tank very quickly at those depths, yet Roy had no backup or additional air supply. He also had no procedures in place for making decompression stops on his way back to the surface.

Roy made several lapses in judgment, all related to planning. If he had thought through what he would do if he speared a large fish — one too large for him to bring to the surface by himself — he might be alive today.

Lessons for Life

1. Nothing you find on a dive is worth your life. Struggling to bring an artifact or a speared fish to the surface is a recipe for disaster.

2. Drop your weights. If you feel yourself struggling on the surface to stay afloat, release your weights. You will be positively buoyant instantly and able to rest and relax while you are rescued.

3. Plan your dive according to the situation.

4. Have the proper equipment for the dive you are making.

5. Stay with your buddy.

Kathy Dowsett

Thursday, June 14, 2012

A. J. Goddard

Discovered and videotaped 2009.

Watch the video on the only known untouched shipwreck from the Klondike Gold Rush—recently (2009) discovered in Canada's Yukon Territory. The steamboat A. J. Goddard sank in 1901, killing three crew members.

This underwater video, taken with a remote operated vehicle, shows the remarkably intact remains of the A.J. Goddard.

The small iron stern-wheel steamboat sank during an Autumn storm in Lake Laberge in 1901.

Three crew members drowned, while 2 others were saved, found floating and clinging to the ships small pilot house, which broke off when it sank.

The wreck is a time capsule: boots and the jacket of one of the crew lie on the deck, along with a stove, scattered dishes and tools. Just prior to the ship sinking, the crew added more fuel to the fire in a desperate attempt to steam to safety. Today, more than a century later, the boiler door, to the left in the video, still lies open with lightly charred wood in the firebox,.

The Goddard was prefabricated in San Francisco and Seattle, and then hauled over the mountains in Alaska and the Yukon to Lake Bennett, where it was assembled.

The steamer operated on the lake and rivers that led to Dawson City as a passenger and freight boat.

And its discovery also shows that the ship was self-sufficient, replete with a small floating repair shop, and kitchen.

The discovery was made by the Yukon River Survey, a project of the Institute of Nautical Archaeology. The surveys latest dive was partially funded by the National Geographic Society/ Waitt Grant program.

Kathy Dowsett

Friday, June 1, 2012

Underwater Navigation for the Novice Scuba Diver

The new dive adventurer is similar to being a passenger on a long ride in a car.

You get to looking around and you have arrived at the destination and have no clue of the route taken to get there. The first couple of lessons you may be fine focusing on your breathing, clearing your ears, clearing of the mask and the awesome joy of the underwater adventure. The sooner you start working on your navigation skills the better, especially if you're learning in a lake that has visibility of twenty feet or less. Because just assured as you are reading this, you will be looking around and in an instant your instructor has disappeared into the darkness. Don't panic just stop for a minute and relax. The instructor will be back for you and if he or she doesn't come back ascend slowly to the surface because they haven't taken you far from the boat or shore. It happens don't worry about it, that is when you realize you need to sharpen your navigation skills.

There are some simple rules to navigation that will make it easier to find the way back to the point of entry. The first and most important is to have a dive plan before you and your dive buddy enter the water, decide who will be the lead diver. Follow the lead diver; let that person concentrate on navigating while the other diver focuses on time, air usage, distance and depth. If you are not the leader it is still important to know your dive plan for emergencies or if you and your dive buddy get separated you can get back to the entry point safely.

If the point of entry is a boat follow the mooring or the anchor line down to the bottom and familiarize yourself with the surroundings. From there follow the dive plan your group has put together. If the entry point is from the shore, swim out to the point you have planned to make the decent. Again get familiar with the surroundings and follow the dive plan.

Navigation underwater isn't any more difficult than above ground navigation. Look for markers, rock formations, sand bars and distinguishing corals of any kind or a tree stump. Anything that is memorable can aid you and your dive buddy in returning to the point of entry. These are just a few tips to make the dive more enjoyable and less stressful.

Article Source:

Kathy Dowsett