Tuesday, August 20, 2013

Monday, June 17, 2013

Expedition searches for Griffin shipwreck in Lake Michigan

Potentially big news about the the Griffin, a 17 century ship commanded by French explorer La Salle.
Steve Libert, head of the expedition seeking the explorer La Salle’s lost ship the Griffin, stands on a fishing boat as dive teams prepare to inspect a site Saturday, June 15, 2013, in northern Lake Michigan where he believes the vessel may have sunk.

Michel L’Hour, director of France’s Department of Underwater Archaeological Research, prepares to dive to what explorers believe may be the site of the long-lost ship the Griffin, Saturday, June 15, 2013 in northern Lake Michigan.

Remote Mich. village abuzz over shipwreck search

Associated Press

  FAIRPORT, Mich. — Commercial fisherman Larry Barbeau's comings and goings usually don't create much of a stir in this wind-swept Lake Michigan outpost, but in the past few days, his phone jangles the minute he arrives home.

Barbeau's 46-foot boat is the offshore nerve center for an expedition seeking the underwater grave of the Griffin, the first ship of European design to traverse the upper Great Lakes. Built on orders of legendary French explorer Rene Robert Cavelier de la Salle, it ventured from Niagara Falls to Lake Michigan's Green Bay but disappeared during its return in 1679.

Divers this weekend opened a pit at the base of a wooden beam that juts nearly 11 feet from the lake bottom, believing it could be a section of the vessel, the rest presumably entombed in mud. They picked up the pace Monday with more powerful equipment after a weekend of probing showed that whatever is buried is deeper than sonar readings indicated.

U.S. and French experts insist it's too early to say whether there's a shipwreck — let alone the Griffin. But anticipation is building at the prospect of solving a maritime puzzle that's more than three centuries old.

"After we get done for the day, everybody calls or comes to the house and they're like, 'What did you find? What did you see? Can you tell me anything?' " Barbeau said in a Sunday interview aboard his ship, the Viking, which holds crucial expedition equipment, including "umbilical" cables that supply oxygen to divers. "People are really interested and they're excited to see what it is."

His neighbors aren't the only curious ones. The roughly 40-member expedition team consists of archaeologists, historians, boat pilots, divers, an underwater salvage crew and assorted helpers. When not on the water, they stay in cottages and tents by the lake in the unincorporated village of Fairport, in one of the most remote corners of Michigan's Upper Peninsula.

Some are relatives or longtime friends of mission chief Steve Libert, who has sought the ship for three decades. While researching the Griffin long ago, Libert ran across Mike Behrens, a Milwaukee sheet-metal worker whose grandfather had searched the lake for chests of gold that legend says smugglers lost during the Civil War.

"I came up here one year to witness what Steve was doing, and I asked if I could dive with him," said Behrens, 54. "Been doing it ever since. ... I've never met anyone as good at research as him, and he's a very ethical guy. If he says it's the Griffin, I absolutely believe him."

Others have come aboard more recently, including three archaeologists from France who arrived over the weekend.

The hands-on excavation work is being handled by a three-man crew from Great Lakes Diving and Salvage, a Michigan company that ordinarily deals with mundane tasks: repairing pumps or scraping zebra mussels off intake pipes.

"We're basically underwater janitors," said Tom Gouin, vice president of operations. The Griffin, he said, is "like a play job for us. We're loving it."

The team has had to adjust its strategy, as the excavation is proving to be a bigger-than-expected challenge.

Sonar scans in years past had suggested that an object similar to the Griffin's reputed size rested about 2 feet beneath the lake floor. But commercial divers found Friday the bottom caked with a thick layer of invasive, fingernail-sized quagga mussel shells.

After tunneling through mussels, the divers began sucking away gravel and sediments, never hitting anything solid. By Sunday night, the hole reached about 8 feet below the lake bed and it wasn't clear how far down the wooden beam extended or what it might be attached to, said Ken Vrana, the project manager.

But as more is exposed, the post appears increasingly likely to be part of a ship, said Michel L'Hour, director of France's Department of Underwater Archaeological Research.

"We never saw a timber standing like this one," he said. "So it's impossible to imagine it otherwise, so one can expect that there is a hull."

Archaeologists Rob Reedy of Morehead City, N.C., and Misty Jackson of Leslie, Mich., sit on the Viking and sift through material that was found in the sediment, watching for artifacts, from bronze cannons to axes or knives — "anything man-made" that would help identify a ship, Reedy said. Thus far, the only candidate has been a slab of blackened wood about 15 inches long with characteristics suggesting it might have been fashioned by human hands. Its origin remains unknown.

Visitors inspired by the long-lost ship have drifted into the area during the search, including a 9-year-old who wrote a school paper about the Griffin and men in period costumes and handmade canoes who in 1976 re-enacted la Salle's journey across the Great Lakes and down the Mississippi River.

Carl Behrend, a folk singer and self-described "pretty-soon major movie star" who lives 90 minutes north on Lake Superior, performed an impromptu concert outside the food tent Sunday night. He said he's composing a song about the Griffin.

"It's rattling around in my head," he said.

Friday, May 31, 2013

Coral triangle is the global center of marine biodiversity

The coral triangle is universally recognized as the “global center of marine biodiversity” and “the Amazon of the seas.”
It is fair to say that most of the Earth’s saltwater species that exist in today’s oceans owe their ancestry to ancient residents of the triangle. Now part of the South Pacific, the coral triangle was once a landlocked lake that formed during the Ice Age when massive blocks of ice sucked up the surrounding water, and land masses appeared from the ocean bottom. When the ice melted, the land was once again covered by water, and the species of the coral triangle propagated first east and west along the equator and then north and south.
Today, the triangle sits roughly in the tropical marine waters of Indonesia, Malaysia, Papua New Guinea, the Philippines, the Solomon Islands and Timor-Leste. All of it sits directly north of Australia. It covers 5.7 million square kilometers of ocean waters. The triangle is home to at least 500 species of reef-building corals and more than 3,000 species of fish, including the world’s largest fish – the whale shark – and the coelacanth. There are more species of coral, fish and crustaceans in the triangle than there are at any other location in the world.
But perhaps the most interesting thing about the triangle is the multitude of yet undiscovered, or, more accurately, scientifically unclassified wildlife that can still be discovered there today. All one has to do is dip below the surface of the water, and they can feast their eyes on an animal that would leave scientists dumfounded.
“You can see things that you’ve never seen before, and possibly things that are new to science that have never been described before,” said Rudy Whitworth who visited part of the coral triangle at Raja Ampat in Indonesia. He spoke about the coral triangle at this year’s Great Lakes Shipwreck Festival.
Whitworth, a member of The Ford Seahorses Scuba Diving Club, which sponsors the festival, said he filmed eight or nine undescribed species, including two that are likely brand new to science: a triple-fin blenny and a species of nudibranch.
“When I went to my experts, the doctorates that do the assigning, the scientists, they said ‘I have definitely never seen this one before.’ That’s really special.”
The uniqueness of the coral triangle is rooted in its role during the Ice Age. As ice cover grew from north and south polar ice caps, global temperatures dropped, and most warm-water species around the globe died. As the ice converged on the triangle area near the equator, the ice sucked up huge volumes of water and the ocean bottom suddenly became a land mass. The triangle area became land-locked and the warm-water species survived due to their comparatively warm location near the equator. Once the Ice Age ended, the ice melted and that ocean bottom was covered with water once again. But the result was the only warm-water species left were those located in the coral triangle.
“They have had longer to evolve. Therefore, there are more species there. So when the ice melted and the water came up, the species that were contained in this area actually went out and propagated all around the equator. And then they started working up and down. So the further you get away from this coral triangle, the fewer species you have. In terms of evolution, they have had less time to evolve.”

Tuesday, May 14, 2013

Michigan's copper mining history starts well before the birth of Christ

Michigan’s Upper Peninsula has been known as “copper country” for hundreds of years.
More specifically, the peninsula’s northwest corner, Copper Harbor, Ontonagon and Eagle Harbor, all part of the Keweenaw Peninsula, at one time were bustling areas of copper mining.
But did you know copper was first mined in our state thousands of years before the birth of Christ? Before the Egyptian pyramids? Before Stonehenge?
Scientists believe copper was first mined in the Upper Peninsula between 3,000-7,000 years ago, or about 5,000-1,200 B.C. During that time, it is estimated 1.5 billion pounds of copper was mined by an unknown civilization.
These people left behind no burial grounds, no dwellings, no pottery or cave drawings. What they did leave behind was thousands of copper producing pits and thousands of crude hammering stones to work the pits. They would alternately use fire and cold water to break copper bearing rock into smaller pieces and then extract the metal with hammer stones.
Because copper is a malleable metal, it was easily shaped and durable. It would be turned into tools, arrows and spearheads, as well as jewelry.
But most of the estimated 1.5 billion pounds of copper mined by these ancient people is no longer in the Upper Peninsula. Where did it go? How was it transported? The pure copper of the Lake Superior region has been found in prehistoric cultures throughout North and South America.
“This is the controversial area of the copper story,” said Luke Clyburn of the Noble Odyssey Foundation, which released its latest documentary, “America’s Ancient Industry” on copper mining in the U.P. “The amount of effort that it took to mine, to be able to travel to Isle Royle, to travel to Keweenaw, there had to be an economic payback.
“It was an industry,” Clyburn continued. “These people were looking at how to exchange it, maybe not for money, but for a commodity that they needed.”
Some experts estimate it would have required 10,000 men 1,000 years to mine the 1.5 billion pounds of copper and develop the extensive operations carried on throughout the region. Others say those numbers are high.
Regardless of the numbers, what often goes unnoticed or forgotten is that these ancient, unknown peoples had far more intelligence than they are given credit for.
“Were they just hunters and gatherers? I don’t think so. I think these people were pretty smart,” Clyburn said. “They knew how to make tools, and they shipped these materials wherever they could and exchange it for commodities that would make it worth their effort.
“They could travel and get back home again. That took a pretty high level of sophistication and navigation. All of that industry created some pretty sharp people.”
Schoolchildren are taught Christopher Columbus discovered America. But that is the Anglo-Saxon history. This region has a rich history developed long before Columbus sailed the ocean blue in 1492. It’s just that so much of it remains a mystery.
“There was clearly a lot of connection with other continents. Maybe it was exploration, maybe it was in search for food, maybe it was an expedition for copper,” Clyburn said. “People traveled back and forth long before what we see in history.”

To purchase Clyburn’s full “America’s Ancient Industry” documentary, go to www.nobleodyssey.org or call Clyburn at 248-666-9359. A $25 donation is to the foundation is required.

Wednesday, May 8, 2013

Ships only become famous after they sink

Most of the time, ships that ply the Great Lakes do so in anonymity.
It’s only when some tragedy befalls them that their name and their service record become history for the rest of the world to learn about.
The Edmund Fitzgerald was just another ship carrying iron ore through the Great Lakes until it famously sank in 1975 in Lake Superior. Singer/songwriter Gordon Lightfoot took it on a rocket ride to legendary status.
Even the Titanic, perhaps the most famous shipwreck of all time, would have been just another luxury steamer until it sunk in the mid-Atlantic in 1912. Sure, at the time it was lauded as one of the biggest, fastest, most luxurious ships ever made. But a lifetime of safe, comfortable ocean crossings would have surely helped it vanish into a mere footnote of history.
Valerie van Heest of Michigan Shipwreck Research Associates, an award-winning author and filmmaker from Holland, Mich., spoke about how ships become famous at a presentation titled “Lost and Found – Legendary Wrecks” at the 32nd Great Lakes Shipwrecks Festival.
“The fact is we learn more about the ship from the discovery of the wreck and the evolution of diving rather than the incident that put the ship on the bottom,” van Heest said.
Archeologically, van Heest said, we can study artifacts and personal objects left in the vessels after they have foundered.  We can learn more about the crew on board than simply a list of the names of those who perished. She described one vessel she dived in which she found personal objects, such as a crew member’s sock with a hole in it, indicating the man wasn’t well-to-do and couldn’t afford new socks. She’s found ships with an array of coins inside from various Scandinavian countries that provide a window into the geographic makeup of the crew.
“These are tremendous artifacts that speak to us by allowing us to study them,” van Heest said.
 Today, shipwrecks owe their survival in large part to relatively new state and federal regulations enacted to protect them from scavengers and treasure hunters looking to either remove things from the ships or lift the vessel itself out of the water altogether.
In 1987, the Abandoned Shipwreck Act was introduced in Congress and signed into federal law in 1988. That law mandated that each state write its own laws to protect shipwrecks and turned  over ownership of the wrecks from the federal government to individual state governments.
In Michigan, for example, the Aboriginal Records and Antiquities and Abandoned Property statute, which includes the Natural Resources and Environment Protection Act which protects shipwrecks, only became law in 1994. That law updated legislation that had been enacted in the state in the late 1970s but was not as comprehensive in scope.
Prior to that, anyone who had the wherewithal to lift a wreck, and the money to pay for it, simply had to obtain the salvage rights. Prior to the writing of the Shipwreck Act, “looting was standard practice by divers, including myself,” van Heest said. But doing so would gut the wreck of important artifacts, and bringing it to the surface would almost certainly spell an end to the vessel.
Van Heest cited as an example the case of the Alvin Clark, a ship that went down in Green Bay, Wis., in 1864. In 1969, a team headed by scuba diver Frank Hoffman lifted the Alvin Clark from the bottom of the bay in what was considered an extraordinary event that was praised by the government, the press and the public alike. The ship was designated a Michigan State Historic Site in 1972 and was listed on the National Register of Historic Places in 1974.
The ship was raised legally in extraordinary condition, completely intact and actually floated once water was removed from its holds. It quickly became a tourist attraction after Hoffman built a museum nearby and exhibited the ship as a tourist attraction at the "Mystery Ship Seaport" in Menominee, Mich.
But neither Hoffman nor its crew accounted for the environmental damage the ship would suffer out of the water – from weather, wind, extreme hot and cold temperatures – much different conditions from the cold, low-oxygen environment at the bottom of Green Bay.
The ship quickly began to deteriorate, decayed and started to fall apart. Hoffman had neither the expertise nor the money to restore the Alvin Clark. His search for grants to pay for repairs fell upon deaf ears.
Finally, in 1994, the same year shipwreck protection was updated in Michigan, the ship was considered beyond saving and deemed a hazard. The Alvin Clark, one of the oldest merchant ships to ply the Great Lakes, with its origins in 1847, was bulldozed and lost to history. And everyone involved learned a valuable lesson. According to van Heest, states across the country were influenced by the story of the Alvin Clark and used it as an example of what could go wrong while authoring their own legislation.
They don’t make them like that anymore
Thanks to improving side-scan sonar technology, van Heest believes all existing shipwrecks will be found in the next 15-20 years. In addition, she said it will take at least another 100 years before time and zebra mussels break down the oldest shipwrecks and turn them into a pile of planks. But fortunately, van Heest’s research has shown the older the shipwreck is, the better it’s made.
Remember how your parents would constantly complain things aren’t built the way they used to be? Well, according to van Heest, that also applies to shipwreck building nearly 200 years ago.
Not only are ships that sit in deeper water better preserved due to colder temperatures and less environmental activity, but older ships, in van Heest’s experience, were simply made better.
“In the heyday of the schooners in the 1870s-‘80s, they were cranking these things out, and I don’t think they were all that well built compared to the ones built in the early 1800s,” she said. “Back then, they weren’t as plentiful, and they were building them better.”
To learn more about legendary Lake Michigan shipwrecks, check out van Heest's book, titled "Lost & Found Legendary Lake Michigan Shipwrecks" by clicking here.

Monday, April 29, 2013

Rebreather opens up a whole new level of scuba diving

Like many divers, Mike Lynch anticipated his venture into the great blue beyond following his open water certification would be peaceful, serene and quiet.
Well, two outta three ain’t bad.
While scuba diving is peaceful and serene, it’s not always quiet, thanks to the never-ending pulse of expelled breaths and the resulting bubbles escaping past the diver’s ear. Breathing air in from a pressurized tank and expelling used air into the water column has always been a part of diving in general and scuba diving in particular.
But for serious divers, and those with both the skills and the disposable income, rebreathers offer a panacea of underwater enjoyment.
In the past year, Lynch, a diving friend of mine who works with Bruno’s Dive Shop in Clinton Township and Titan Dive Group, became a certified rebreather diver, and the stories he has to tell are amazing. Four-hour cave dives with an average depth of 120 feet and such quiet tranquility that he can hear the water moving around in the cave system and rocks cracking on each other as they roll around in moving water. Fish swimming right up to his mask to see their reflection because they aren’t scared away by expelled bubbles.
“It brings you into a whole new world of diving,” Lynch said.
Lynch, repping Titan at the Great Lakes Shipwreck Festival in March, gave me an up-close and personal explanation of how the rebreather works.
In the most basic terms, the rebreather uses two tanks, one containing pure oxygen, and the other containing regular air used as “filler.” Each tank is smaller than a traditional scuba tank. With each breath, the used air is recirculated using a scrubber to remove the carbon dioxide, and additional oxygen is added to the “filler” air. The system is constantly evaluating the user’s gas needs based not only upon their own metabolic rate, but also things like the dive depth. According to Lynch, it creates a perfect nitrox mix for the entire dive.
It is a much, much more efficient way to use gas, since it is all recycled and reused. A typical “open circuit” scuba unit, with expelled bubbles, wastes a significant amount of oxygen. In a typical breath, only about 4-5 percent of the oxygen is used, and the rest is expelled into the water. With a rebreather, that unused oxygen is pushed back in the system and mixed with the filler air and oxygen. Lynch said that during his four-hour cave dive at an average of 120 feet, he only used eight cubic feet of oxygen.
While the idea and the concept of rebreathers have been around for more than 200 years, mass-produced recreational rebreathers have only been around for a little more than 20 years. The last 10-15 years have seen significant technological advancement.
Nevertheless, cost remains an issue. Lynch said a diver looking to get into rebreather technology can expect to spend about $10,000 for the equipment, the training and the gas to get started.
In the video above is my interview with Mike Lynch and our discussion about rebreathers.

Monday, April 22, 2013

State police trooper recounts Cessna crash in Lake Michigan in which two people were trapped in the back seat

Michigan State Police Sgt. Bill House admits he has seen a lot and “been in a lot of bad places” in his 13 years as a member of the force’s underwater rescue and recovery unit.
But one incident still gets to him and chokes him up nearly three years after it occurred: That is the case of a Cessna 206 that crashed in Lake Michigan about four miles off the coast of Ludington on the morning of July 23, 2010. The crash killed four of the five passengers. But it was the way that two of the victims were killed that House acknowledges bothers him to this day.
“I think of it now and the thought of them and what went on, yeah, it still bothers me. I can still see their faces as clear as the day it happened,” House said.
The tragic story began on July 23, 2010, when pilot Jerry Freed, co-pilot Earl Davidson, medical doctor James Hall, cancer patient Donald Pavlik, who was superintendent of the Alma Public Schools, and his wife Irene set out on a flight from Ludington to the Mayo Clinic in Rochester, Minn., where Pavlik was to receive cancer treatment. The aircraft developed engine trouble, eventually determined to be a faulty fuel filter. The pilot turned around in the hopes of making it back to Ludington.
They never made it.
The aircraft crashed into the lake that morning. While attempting to land the plane in the lake, the pilot lowered the flaps to flare the plane out. The Cessna hit the water, the engine was ripped off, and the fuselage flipped upside down. The pilots and the doctor, who were all sitting in the front seat, got out. Pavlik and his wife remained inside.  Because the flaps were locked into their extended position, blocking the rear door, they were prevented from opening it. The flaps couldn’t be moved because the engine was ripped off the plane.
“They were basically trapped in the plane,” House said.
Six days later, Sgt. House and his dive team’s side-scan sonar s made contact with the plane, finding it in 173 feet of water, about three to four miles from the shore between Big Sable Point and Ludington harbor. The Pavliks were still in the back seat -- Don Pavlik still strapped in his seat belt, Irene Pavik resting on his lap.
“It looked like he was hugging her. And it looked like she was trying to get the door open,” House said, his voice choking at the memory.
House and his dive team were actually fairly close to the accident scene when the plane went down. Normally based in Coldwater, House and other rescue team divers were training in Rodgers City when they got the call and immediately headed toward Ludington. They gathered information from the ELT (emergency locator transmitter) that was activated when the plane hit water. Within six hours of the plane going down, the dive team was on the water, setting up a square-mile perimeter grid around the beacon and began side-scan sonar searching. The search came up empty.
The team headed back to shore, talked to a charter boat captain who had seen the plane go down, looked at the FAA flight path that had been recorded prior to the plane dropping below radar and received information from the pilot, who had been picked up by a nearby boat. The team went back out and set up a two-square-mile grid with two crews working 24-hour shifts in an attempt to locate the aircraft. In addition to the difficult environment, the search was hampered by the sonar equipment becoming tangled in commercial fishing nets.
Finally, in the early evening hours of July 29, the crew found the plane upright on the bottom of the lake and the engine nearby. The first recovery dive took place at 7:20 p.m. That’s when divers found the Pavlik’s bodies still seated inside the plane and the reason why they couldn’t open the rear door.  The following morning, the dive team cut the flap actuator rod that held the flaps in the open position and recovered Irene Pavlik. The resulting silt from removing Mrs. Pavlik left zero visibility. That, combined with floating luggage, entangled medical equipment, the width of the diver’s double tanks and the narrowness of the doorway made it impossible to remove Mr. Pavlik. He was recovered later that day.
On July 31, Dr. James Hall was recovered nearby the plane, and on Aug. 1, Earl Davidson’s body was recovered, also near the plane. Presumably, both men drowned sometime after exiting the plane. Only the pilot survived the accident.
It was the deepest recovery dive since the inception of the Michigan State Police underwater rescue unit in 1957, and House’s deepest personal dive. It was also fraught with difficulty, dealing with the environment, the lack of visibility, the wind and the waves and its location so far offshore.
But as is the nature of his job, each day has its rewards and its heartbreak.
“It’s one of those bittersweet things. I love diving. I love state police diving and the recovery work because somebody’s got to do it,” House said. “I’ve been told ‘this is a gravesite, shouldn’t you leave it alone?’ But people want their loved ones back, and so that’s part of it you feel good about. You are excited when you got them out of the plane, but it’s also very tragic.”

Wednesday, April 10, 2013

Alpena-Amberley land bridge reveals more evidence of prehistoric caribou hunting from 100 feet below the surface of Lake Huron

Dr. John O’Shea has a bottle of Scotch whiskey on the desk in his office, a gift from a colleague. The problem is, he’s not allowed to open it.
Not allowed, that is, until the colleague who gave it to him gives him the OK.
Since the summer of 2009, O’Shea, the curator of Great Lakes Archaeology in the Museum of Anthropology at the University of Michigan, has led a study of the Alpena-Amberley ridge, a 72-square mile post-Ice Age land bridge that once connected what is now Michigan’s northeastern Lower Peninsula near Alpena, with Point Clark in southwest Ontario about 9,000 years ago. Today, that ridge sits 100 feet below the water line at the bottom of Lake Huron.
In the 3-1/2 years his team has been studying the area, it has found compelling evidence that both caribou and mastodon used the ridge as a semi-annual migration path, and that humans, categorized as Paleoindian and Early Archaic hunters, devised ways to hunt and kill the animals on the ridge. But a skeptical colleague, that’s right, the one bearing the gift of Scotch, won’t be convinced until the group finds an arrowhead or a spearpoint, thereby in his mind confirming O’Shea’s theory.
“I want to be out there until I find that spearhead and I can open that bottle of Lagavulin,” O’Shea said with a laugh. “We’ve convinced a lot of skeptical critics that this probably is what was going on. The dates (carbon dating of wood poles found to be about 9,000 years old) are coming in, the simulation is working. Science is incremental, you’re always adding things together. But the pieces are falling together in a really nice way. So I’m very enthusiastic about this summer’s work that we will collect even more stuff.”
O’Shea has been a frequent visitor at the annual Great Lakes Shipwreck Festival, and once again spoke to a packed room, updating listeners on scientific findings in 2012.
On older nautical charts, the area including the ridge is labeled as the Six Fathom Shoal, and it once divided the Lake Huron basin into two distinct lakes, the largest of which is called Lake Stanley. Scientists believe the ridge exists because it is composed of limestones and dolomites, materials so hard that even the mighty glaciers that destroyed everything their path couldn’t cut into it.
While the ridge area includes the prehistoric Lake Stanley, Lake Chippewa, the forerunner to Lake Michigan sat to the west. Prior to the ice melt that eventually covered the Alpena-Amberly ridge, those two lakes did not connect at the Straits of Mackinac like they do today.
A computer rendering of the Alpena-Amberley land ridge, a 75-square mile ridge that once connected Michigan's Lower Peninsula to southwest Ontario. The green area represents the current water line of Lake Huron.
In years past, the team had found wooden poles, perhaps used to hang meat, that date to about 9,000 years ago. They found stone structures probably used as hunting blinds, caches or pits and “drive lanes” made by a linear path of rocks that would bring the animals close enough that hunters could attack them with spears and lances.
In 2012, the team discovered additional wood samples, potential fireplaces, charcoal, and in core samples flakeage or micro-debitage, stone microfragments made when chipping away at stone or rock to make tools, weapons or other implements. The microfragments are determined to be manmade since the way they are shaped couldn’t have happened naturally. The team is also transitioning from discovering artifacts to determining how the people of that time period lived.
Since it was during the post-Ice Age time period, the climate was milder than the Ice Age, but still bitterly cold with miserable conditions along the ridge. Those "warmer" conditions were comparably pleasant for the caribou and their thick hides. The subarctic tundra would have had developing grass areas, intermittent marshes and a scatter of coniferous trees, while the water’s edge would have provided various types of vegetation. The windy conditions would have given them relief from flies that bothered them during the warmer seasons. As for the hunters, the confined nature of the ridge would have provided a substantial element of predictability regarding herd movement which would have been of great value to them.
“These people probably lived in the Lower Peninsula, closer to the middle of the modern-day lake since the lakes were so much shallower then,” O’Shea said. “They probably only came out to the ridge to hunt. Maybe they would come out by sled in the winter to retrieve the meat that had been cached from the fall hunt.”
While many of the hunting blinds at the bottom of Lake Huron are set up to attack caribou moving in both migrational directions (southeast in the autumn to rut and northwest in the spring to calve) some are V-shaped, giving the impression that they would work for movement in only one direction. Based upon which direction they are facing, scientists can determine whether they were used for fall or spring migration. In addition, some blinds are minimal, suggesting their location didn’t work, while other blinds are more extensive and updated, indicating they are in better locations and fortified to allow for more hunters.
“A number of the structures are located on high ground at the break of the crest of a hill, so that the animals coming up the hill don’t really see (the hunters) until they are upon them,” O’Shea said. “They did things that make a lot of sense to a modern hunter’s eye.”
As for the final smoking guns, such as large pieces of bone or spear or arrowheads that would remove all doubt of hunting activity on the ridge, O’Shea said large or macro bone pieces almost certainly have dissolved over time. The microbone fragments that have been found were discovered in core drilling samples. Larger pieces of bone would only be found in holes or caches within the limestone.
The spear or arrowheads are still on the agenda and will hopefully be discovered, if only so O’Shea can uncork his whiskey. 
When asked if his team has made enough discoveries to certainly prove the existence of hunting on the ridge, his answer is one you may expect of a scientist.
“We’ve gone a long way towards ‘certainly,’ but I wouldn’t say absolutely … yet,” he said.
This summer, O’Shea’s team has plans to look for additional campsites, devise better means of collecting bulk sediment samples and search for cultural debris, expand the search to natural migration choke points and expand acoustic coverage.

Thursday, April 4, 2013

A new way to look at gas consumption using rock bottom: Why simply planning to surface with 500psi isn’t the best way to manage air

This article was provided to me by James Mott of Unified Team Diving and Sea The World Scuba Center.  I met James at the Great Lakes Shipwreck Festival in which he spoke on the topic of gas management. James shared the concept of “rock bottom” in which divers determine when is the best time to begin an ascent from the deepest part of the dive to allow for a safe reserve of 500 psi when reaching the surface. Also check out the video interview I did with James at the festival.

By James Mott

Throughout the world, divers are told again and again to return to the boat with 300-500 psi in their tanks.  Understandably, most competent divers stretch their bottom time out as long as they can.  They smile as they show their pressure gauges to the dive master upon surfacing and then compare gauges with other divers in order to see who the closest one to 301psi is.  Getting the most bottom time underwater is a fun game to play with buddies and I’m not saying that divers shouldn’t use as much of their tanks as possible.  However the question becomes, “Is this the smartest way to plan gas?” What exactly is the goal of leaving some air in our tanks?  To help a buddy in need, to keep water out of our tanks, to inflate our BCD’s at the surface?  Many divers use the 1/3’s rule, but even this plan has numerous flaws.  So where do we start?  Is there a plan that works for deep-diving technical divers and shallow-water recreational divers alike?  What is wrong with the idea of surfacing with a safe amount of gas, like 500psi?
The answer to the 500psi problem is that being on the surface at the end of the dive with 500psi does not answer the more important question for scuba divers, which is, “When do I have to leave the bottom?  If we have an emergency and we need to share air, “How much air will I need to bring me and my buddy to the surface safely?  This is the question that should start all gas planning.
Doing It Right (DIR) education teaches the unified team to plan for the worst possible emergency before the dive starts.  We always ask the question, “What happens if at the worst possible moment, the deepest part of the dive, the furthest distance from home… my buddy runs out of air… How much gas do I need to bring both of us to the surface without any incident?”
Calculating rock bottom is easy enough to do in your head before the dive and it is taught in all entry level DIR courses.  How long will the ascent take, multiplied by two divers, then by the average depth and then by a consumption rate, equals rock bottom.
Rock bottom is calculated by adding up the time it would take to ascend from a given depth.  For example, from 60 feet, we would normally ascend at 30 feet/minute and have a three-minute safety stop.  This normal ascent would take us four minutes.  We then add one minute for the air-sharing emergency to take place and have a five-minute ascent, requiring 10 minutes of total air with two divers breathing during that 5 minute time frame.  We assume we have an elevated breathing rate of about 1 cubic foot/minute.  Our average depth during the ascent is about 30 feet or 2 ATA (atmospheric pressure one ATA is atmospheric pressure at sea level) where we consume gas at twice the surface rate.

5 minutes X 2 divers X 1 cfm X 2 ATA = 20 cubic feet of gas
20 cf of gas on an AL 80 is about 750 psi.
Rock Bottom for 60 FSW on an AL80 is 750 or for most gauges, 800 psi.

Rock Bottom for 100FSW on an AL 80 is 1600psi.  (Math is not provided but can be, just ask.)
Once rock bottom is determined, the remainder of the useable gas is then divided into a logical plan.  Maybe it is a drift dive on a Caribbean reef where we can use everything. Maybe we are diving on a shipwreck in the Great Lakes and need to get back to the mooring line, or we might be doing a penetration on this shipwreck where we will need enough gas to get out of the wreck plus enough to get to the surface.  Different dives will require different gas plans, but rock bottom must always be accounted for, before the gas plan is made.  DIR education teaches the unified team to plan their gas in accordance for the specific dive, so that each diver can get the most fun possible out of their diving and still be safe.
Being at depth below rock bottom is irresponsible and will not give us enough air to safely ascend.  The only emergency underwater is running out of gas, everything else is just an inconvenience.  Once the out of gas diver is breathing again, we move from emergency to management.  Just because someone ran out of air, does not mean that we rush to the surface, exceed safe ascent rates, skip safety/deco stops, or anything else we know about safe diving protocols.  The only option is to remain calm, think, communicate and finish the dive.
For more information about rock bottom or other gas management options, contact me at jm@unifiedteamdiving.com or www.unifiedteamdiving.com or Sea The World Scuba Center in Farmington Hills at 248-478-6400.