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--part1_8e.148f6a6e.2817af60_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit My familiarity with cold water diving is limited to fresh water: the Great Lakes and inland lakes in Michigan. The lowest temperature I recall in my diving is 37 degrees, which was a pretty standard temperature for a number of these dives. Sometimes, temperatures would climb to the low 40's at depth. I've dived Scubapro regs and never had a free flow. Prevention has to do with equipment maintenance and procedures for diving: 1. The regulator first stage should be de-tuned slightly (Trey has explained this all before). 2. When ice diving or diving in cold weather, do not test the regulator and breathe from it on the surface. This potentially allows moisture from your breath to cause a freeze up. 3. Too much demand on the first stage can cause a freeze up there. Try not to inflate and inhale at the same instant with the same first stage. Be aware that a gas sharing situation (with a single first stage) has a potential to result in a free flow too. I'm unable based on experience to compare cold salt water vs. cold fresh water, other than to say that the salt water would freeze at a lower temperature because of the dissolved salts and minerals. I don't know if there are properties of the salt water that affect regulator free-flow/freeze-up in some way. I do know that you'll have to rinse your gear more thoroughly after the dive in salt water. JS In a message dated 4/24/01 2:10:52 PM Eastern Daylight Time, klind@al*.ne* writes: > Wendell: > > Obviously saltwater freezes at a lower temperature than fresh water. That's > why the put salt on the roads. > > There's a place in Juneau where the highway runs on a narrow roadbed with a > lake on one side and the ocean channel on the other side. Most of the > winter the lake is frozen solid while the channel is open water and free of > ice. > > In addition to that, when seawater does freeze, it is a more slushy and > crumbly ice, not the sharp hard glassy stuff you get with freshwater. > > The question though, is what causes a regulator to freeze? Is it the > seawater that washes into the balance chamber of the regulator that freezes > and causes failure? Or is it moisture in your breathing gas that condenses > and freezes to cause failure? > > I suppose that either could cause a reg to fail. I've never torn apart a > frozen reg to see what went wrong. However I suspect that ice forming > inside the air pathways of the regulator from moist air is the more common > failure. In which case the medium you're diving in would not be a factor. > > On the other hand, you guys in the Great Lakes sure seem to have a lot more > problem with freezing than we do here in Alaska. I used to dive MK20s all > winter in mid-30s degree water and never have any failures. And I know > people who sport dive for king crab in the winter with all kinds of old clap > trap gear without problem. Horrifying stuff like old Dacor regs. I > recently switched to Apeks DS4 firsts because they were cheaper and more > reliable and I've never had one of those fail either. But I hear about you > guys in the Great Lakes having regs fail all the time. So maybe regs do > freeze faster in freshwater. > > Kent Lind > Juneau, Alaska > Visit my web page with underwater and other photos at http://members.aol.com/jsuw3/index.html --part1_8e.148f6a6e.2817af60_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: 7bit <HTML><FONT FACE=arial,helvetica><FONT COLOR="#800040" SIZE=2 FAMILY="SCRIPT" FACE="Comic Sans MS" LANG="0">My familiarity with cold water diving is limited to fresh water: the Great <BR>Lakes and inland lakes in Michigan. The lowest temperature I recall in my <BR>diving is 37 degrees, which was a pretty standard temperature for a number of <BR>these dives. Sometimes, temperatures would climb to the low 40's at depth. <BR> <BR>I've dived Scubapro regs and never had a free flow. Prevention has to do <BR>with equipment maintenance and procedures for diving: <BR> <BR>1. The regulator first stage should be de-tuned slightly (Trey has explained <BR>this all before). <BR> <BR>2. When ice diving or diving in cold weather, do not test the regulator and <BR>breathe from it on the surface. This potentially allows moisture from your <BR>breath to cause a freeze up. <BR> <BR>3. Too much demand on the first stage can cause a freeze up there. Try not <BR>to inflate and inhale at the same instant with the same first stage. Be <BR>aware that a gas sharing situation (with a single first stage) has a <BR>potential to result in a free flow too. <BR> <BR>I'm unable based on experience to compare cold salt water vs. cold fresh <BR>water, other than to say that the salt water would freeze at a lower <BR>temperature because of the dissolved salts and minerals. I don't know if <BR>there are properties of the salt water that affect regulator <BR>free-flow/freeze-up in some way. I do know that you'll have to rinse your <BR>gear more thoroughly after the dive in salt water. <BR> <BR>JS <BR> <BR> <BR>In a message dated 4/24/01 2:10:52 PM Eastern Daylight Time, klind@al*.ne* <BR>writes: <BR> <BR></FONT><FONT COLOR="#000000" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0"> <BR><BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Wendell: <BR> <BR>Obviously saltwater freezes at a lower temperature than fresh water. That's <BR>why the put salt on the roads. <BR> <BR>There's a place in Juneau where the highway runs on a narrow roadbed with a <BR>lake on one side and the ocean channel on the other side. Most of the <BR>winter the lake is frozen solid while the channel is open water and free of <BR>ice. <BR> <BR>In addition to that, when seawater does freeze, it is a more slushy and <BR>crumbly ice, not the sharp hard glassy stuff you get with freshwater. <BR> <BR>The question though, is what causes a regulator to freeze? Is it the <BR>seawater that washes into the balance chamber of the regulator that freezes <BR>and causes failure? Or is it moisture in your breathing gas that condenses <BR>and freezes to cause failure? <BR> <BR>I suppose that either could cause a reg to fail. I've never torn apart a <BR>frozen reg to see what went wrong. However I suspect that ice forming <BR>inside the air pathways of the regulator from moist air is the more common <BR>failure. In which case the medium you're diving in would not be a factor. <BR> <BR>On the other hand, you guys in the Great Lakes sure seem to have a lot more <BR>problem with freezing than we do here in Alaska. I used to dive MK20s all <BR>winter in mid-30s degree water and never have any failures. And I know <BR>people who sport dive for king crab in the winter with all kinds of old clap <BR>trap gear without problem. Horrifying stuff like old Dacor regs. I <BR>recently switched to Apeks DS4 firsts because they were cheaper and more <BR>reliable and I've never had one of those fail either. But I hear about you <BR>guys in the Great Lakes having regs fail all the time. So maybe regs do <BR>freeze faster in freshwater. <BR> <BR>Kent Lind <BR>Juneau, Alaska <BR></FONT><FONT COLOR="#000000" SIZE=3 FAMILY="SANSSERIF" FACE="Arial" LANG="0"></BLOCKQUOTE> <BR></FONT><FONT COLOR="#800040" SIZE=2 FAMILY="SCRIPT" FACE="Comic Sans MS" LANG="0"> <BR> <BR><B>Visit my web page with underwater and other photos at <BR>http://members.aol.com/jsuw3/index.html</B></FONT></HTML> --part1_8e.148f6a6e.2817af60_boundary-- -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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