Cold Water Regulator Blues

It’s a black art, the making of scuba regulators for use in polar extremes; or so it seems. Many have tried, and many have failed.

Once you find a good cold water regulator, you may find they are finicky, as the U.S. Navy recently discovered. In 2013 the Navy invested almost two hundred hours testing scuba regulators in frigid salt and fresh water. What has been learned is in some ways surprising.

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Looking at a pony bottle that saved a diver when both his independent regulator systems free-flowed at over 100 feet under the thick Antarctic ice.

DSCN3557cropThe Navy has been issuing reports on cold water regulator trials since 1987. In 1995 the Navy toughened its testing procedures to meet more stringent diving requirements. Reports from that era are found at the following links (Sherwood, Poseidon).  (Here is a link to one of their most recent publicly accessible reports.)

The Smithsonian Institution and the Navy sent this scientist to the Arctic to help teach cold water diving, and to the  Antarctic to monitor National Science Foundation and Smithsonian Institution funded trials of regulators  for use in the under-ice environment. What those studies have revealed have been disturbing: many regulator models that claim cold water tolerance fail in the extreme environment of polar diving.

The Navy Experimental Diving Unit (NEDU) has developed testing procedures that are more rigorous than the EN 250 tests currently used by European nations. (A comparison between US Navy and EN 250 testing is found on this blog). All cold water regulators approved for U.S. military use must meet these stringent NEDU requirements.

Nevertheless, we learned this year, quite tragically, that the Navy does not know all there is to know about diving scuba in cold water.

For example, what is the definition of cold water? For years the U.S. and Canadian Navies have declared that scuba regulators are not likely to freeze in water temperatures of 38° F and above (about 3° C). (The 1987  Morson report identified cold water as 37° F [2.8° C] and below). In salt water that seems in fact to be true; in 38° F scuba regulators are very unlikely to fail. However, in fresh water 38° F may pose a risk of ice accumulation in the regulator second stage, with resultant free-flow. (Free-flow is a condition where the gas issuing from the regulator does not stop during the diver’s exhalation. Unbridled free flow can quickly deplete a diver’s gas supply.)

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The regulator on the left free-flowed, the one on the right did not.

While a freshly manufactured or freshly maintained regulator may be insensitive to 38° F fresh water, a regulator that is worn or improperly maintained may be susceptible to internal ice formation and free-flow at that same water temperature. There is, in other words, some uncertainty about whether a dive under those conditions will be successful.

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An isolator valve that can be shut to prevent loss of gas from a free flowing regulator.

That uncertainty can be expressed by a regulator working well for nine under-ice dives, and then failing on the tenth. (That has happened more than once in Antarctica.)

That uncertainly also explains the U.S. Antarctic Program’s policy of requiring fully redundant first and second stage regulators, and a sliding isolator valve that a diver can use to secure his gas flow should one of the regulators free flow. There is always a chance that a regulator can free flow in cold water.

A key finding of the Navy’s recent testing is the importance of recent and proper factory-certified maintenance.  Arguably, not all maintenance is created equal, and those regulators receiving suspect maintenance should be suspected of providing unknown performance when challenged with cold water.

This finding points out a weakness of current regulator testing regimes in the U.S. and elsewhere. Typically, only new regulators are tested for tolerance to cold water. I know of no laboratory that routinely tests heavily used regulators.

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Weddell seal on the Antarctic sea ice. Photo copyright Samuel Blanc. (From Wikimedia Commons).

Considering the inherent risk of diving in an overhead environment, where access to the surface could be potentially blocked by a 1400 lb (635 kg), 11 foot (3.4 m) long mammal that can hold its breath far longer than divers can, perhaps it is time to consider a change to that policy.

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About to descend through a tunnel in 9-feet of ice on the Ross Ice Shelf.

 

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A huge Weddell Seal blocks the diver’s entry hole. He looks small here, but like an iceberg, most of his mass is underwater.

 

 

McMurdo Station, Antarctica: A Research Town

A photo of Jello Wrestling among fully clothed adults was published today as an indictment of the National Science Foundation (NSF) and its off-duty recreation program for McMurdo Station, Antarctica. Since I’ve spent a little time at McMurdo Station, I’d like to come to the defense of the NSF – by doing nothing more than describing what life in Antarctica is like.

I am not, and have never been an employee of the National Science Foundation, and have never held an NSF grant. I’ve never participated in a Jello wrestling match, although it looks like fun.  So, I am unbiased about this news event. However, I am informed about the rigors of daily life at McMurdo Station.

The following link is to a Washington Times article reporting on a supposed tally of $3 billion of financial excesses within the NSF. http://www.washingtontimes.com/news/2011/may/26/tax-dollars-shrimp-treadmills-jell-o-wrestling/

What is most concerning to me, is that the Coburn report focuses on a non-science activity, designed to relieve interminable boredom in a minimalistic environment. I think that, if pressed, the report’s author would have to admit the photo has nothing whatsoever to do with waste in science funding. How much can Jello bought in bulk for the McMurdo cafeteria cost?

Click for a larger image.

As the Google image above shows, men and women who support the McMurdo and South Pole Station are isolated by vast distances from “civilization”. The closest cities with air transportation to the U.S. bases are either in Christchurch, New Zealand, or in Chile. During the winter, with 24 hours of darkness and generally horrible weather, it is virtually impossible for anyone to leave the bases. There are no flights into or out of the continent. So if anyone developes a medical problem or injury too great for the local medical support staff to handle, they are simply out of luck.

During the winter months, the size of support and scientific staff are greatly reduced, so those sharing the bleak winter together get to know each other, well. The contract staff during both winter and summer is composed largely of young, college-age men or women who are healthy, energetic, and are signing on for adventure.

But think about it. With 24 hours of darkness during the winter, the opportunities for recreation are minimal. It typically isn’t safe, or even possible, to go for walks or runs outdoors. A trip away from base, or even close by, could prove fatal if the weather were to change suddenly, which it often does. There are no soccer fields, no ball parks. And even worse, for those of you forever connected to the Internet,  there is barely enough bandwidth down there to support email on a bank of shared computers. Want to send a photo of yourself home to the folks? Forget about it. At least that’s how it was when I was there a couple of years ago.

View from Hut Point, McMurdo. Click for a larger image.

Life in Antarctica, at its best, is a spartan existence in a harsh, unforgiving environment. So how do these young men and women entertain themselves?

The fact of life is that off-duty entertainment, anywhere in the world, can lead to pregnancy, which in Antarctica can easily become a medical emergency.  And medical emergencies can lead to drama very quickly since flights out of McMurdo are nonexistent in the winter and difficult to arrange, and very expensive, even during the summer. So group entertainment that keeps these young healthy adults occupied is a wonderful idea.

I admit I do not know all the facts behind the firing of the Jello Wrestling organizer, reported in various news accounts.  But I have to wonder: why would off-duty entertainment be a reason to very publicly condemn the organization that funds and staffs the McMurdo Station, and funds a large proportion of science research in the U.S.? 

McMurdo Station seen from the Ross Ice Shelf

As a scientist I do not understand the denigration of the noble discipline that helped our country attain greatness, defend itself, and lead our way into the future. If science is to be attacked in public, I would ask that those attacking it be held accountable for the damage they do to science institutions, and to the minds of young men and women on the verge of becoming scientists. As a country we decry our failing leadership in science and engineering, and complain of the poor quality of education in the math and science disciplines, and yet we allow, and even fund,  studies that criticise  programs that have long been working safely and productively in the harshest environment on Earth.

The U.S. Antarctic Program is a success story, in spite of what headlines of the day might suggest.

Diving Under Antarctic Ice

You are 100 feet down using scuba, with your dive light spotlighting the most exotic looking Sea Hare you’ve ever seen.

It’s noon at McMurdo Station, Antarctica but it’s dark at your depth because between you and the surface of the Ross Sea lies19 feet of snow-covered ice.  Your dive buddy has drifted about 100 feet away, but you can see him without hindrance in the gin clear water of the early Antarctic springtime.

The 800 foot water visibility also means you can easily see the strobe light hanging on the down line 200 feet away, the line leading to the three and a half foot diameter hole bored through the ice.

Under these conditions, you should not have to worry about your regulator, but you do, because you know that any scuba regulator can fail in 28° F water, given enough opportunity. You also know that some regulators tolerate these polar conditions better than others, and you are using untested regulators, so yours might free-flow massively at any moment.

Should that happen, you have a back-up plan; you will shut off the free flow of air from your failed regulator with an isolation valve, remove the failed second stage from your numb and stiff lips and switch to a separate first and second stage regulator on your bottle’s Y-shaped slingshot manifold, after first reaching back and opening the manifold valve. Of course, that backup regulator could also free-flow as soon as you start breathing on it – as has already happened to one of your fellow test divers.

In that situation you would have no choice except to continue breathing from what feels like a torrent of liquid nitrogen, teeth aching from the frigid air chilled to almost intolerable temperatures by unbridled adiabatic expansion, until you reach your dive buddy and convince him that you need to borrow his backup regulator. Once he understands the gravity of the situation, that two of your regulators have failed, then the two of you would buddy-breathe from his single 95 cu ft bottle as you head slowly towards the strobe marking the ascent line. And of course he will be praying that his own primary regulator doesn’t fail during that transit.

Once you reach the ascent line you are still not out of difficulty. The two of you cannot surface together through the narrow 19-foot long borehole. So you would remove your regulator once again and start breathing off a pony bottle secured to the down line. Once it is released from the line, you can then make your ascent to the surface; but only if a 1300-pound Weddell seal has not appropriated the hole. In a contest for air, the seal is far more desperate following an 80 minute breath-hold dive, and certainly much more massive than you. Weddells are like icebergs – their cute small face sits atop a massive body that is a daunting obstacle for any diver. 

But you even have a plan for that — you’ve heard that Weddell seals don’t like bubbles, and they get skittish about having their fins tugged on, and will thus relinquish the hole to you. … At least, that’s what you’ve been told. You certainly hope he would leave before you consume the meager amount of air in your pony bottle.

The text above was taken from a U.S. Navy Faceplate article I wrote concerning  a 2009 Smithsonian Institution sponsored diving expedition to Antarctica in which I participated. On and under-the-ice photos were taken by expedition members Drs. Martin Sayer and Sergio Angelini.