Shortypots
Guest
40* and they were diving? I do not even like to go outside when it is 40*!!! 
So Gino, where you guys off to next?
So Gino, where you guys off to next?
Just did my first Open Water dive at Pleasant!
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OP
SBP Studios
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Shortypots:40* and they were diving? I do not even like to go outside when it is 40*!!!
So Gino, where you guys off to next?
August 11th...Maui to Dive Black Rock and a couple other nice Dives there.
Cant wait!!:lol:
Shortypots:
Congratulations on your open water cert! That's a great achievement. You should come out to Lake Pleasant for some non-open water class diving. We were there the past 3 days (with a small open water class) and had 20 ft of visibility! We also finished up an AOW cert with someone who was diving Tahoe last week. He had great things to say about the diving there. It was a little chilly, though, but I don't think quite at 40 deg.
I'm surprised your instructor didn't review some of the altitude considerations prior to your open water class. Lake Pleasant is at altitude. Come out to the lake one weekend when we're there and we'll go over the altitude info with you.
OP
SBP Studios
Contributor
Dive-aholic:
Care to elaborate on this?
scrapdizzy:
I'll say this much on the Board, diving at altitude makes the RDP invalid. The depths and NDLs aren't applicable at any elevations greater than 1000 feet. This means adjustments need to be made for you to dive safely. Open water dives at Lake Pleasant will never get you out of the safety limits, but student divers should still understand that there's a difference. Otherwise they might think it's okay to head over to Lake Mead or Parker Canyon Lake and dive without making the adjustments. That's not safe. I make it a point to discuss this information with my open water divers. We log the dives and figure out pressure groups based on the theoretical depths. You want more elaboration, then come out to the lake. There's too much to include it all here.
OP
SBP Studios
Contributor
Im just curious what basic adjustments your referring to?
Depth calculations. Your gauge or computer (unless it adjusts automatically) will provide you with your actual depth, but you are diving at a deeper theoretical depth as far as your nitrogen uploading is concerned. I've been diving places where I've had to add 20 feet to my actual depth. Other locations require you to add even more.
Shortypots
Guest
Actually, they did quickly go over the addition of 10 ft to the depth in class, but said it is so nominal at the lake, not to worry about it. I remember Denise mentioning it when we were in the water.
OP
SBP Studios
Contributor
Also the better computers adjust automatically I believe. Dont quote me on that but I believe so.
An "Altitude Dive" is defined as any dive made at 300 meters/1000 feet or greater above sea level. Lake Pleasant is at about 1700 feet above Sea Level. Since (most) decompression models, dive tables and computers were developed for use at sea level, we need to modify our dive profiles to adapt to the changes in pressure as a result of our increase in atmosphere. Decompression models control the release of nitrogen absorbed during your dive by assuming you will begin and end you dive at sea level under a full atmosphere of pressure.
When you are away from the coast, like we are in Arizona, we have to accomodate for the increase in altitude where there's less air pressure. Thus Altitude Diving requires special table or computer procedures to account for the atmospheric pressure difference. While the decompression model difference is minimal at Lake Pleasant, it should not be ignored. Always follow the proper procedures, no matter how minimal the risk differential. Diving at altitude without following the proper altitude procedures increases the risk of decompression illness.
Without getting into the whole Altitude Diver Specialty Class:
Divers with computers make altitude adjustments by reviewing the owners manual. If their computer changes automatically, then no action is needed on their part. However, it has been my experience that computer altitude preferences need to be set. In the case of Suunto computers, they have an altitude setting of (A0, A1, A2, and A3). A0 is obviously sea level and A1-3 is a range setting. For Arizona, we use the A1 Setting which is calculated up to 3000 feet or 4000 feet (I don't exactly remember).
Divers with tables make altitude adjustments by planning their dive for a theoretical depth. Following is a link to a chart that was printed by Skin Diver Magazine that looks very similar to the one I use.
http://www.sandiasnorkel.com/info/inf-g_10.php
With this, you take your actual depth, convert it to a theoretical depth depending on your altitude, and plan your dive accordingly. Please note the difference for safety stops.
Lastly, there is a lot more covered in relation to Altitude Diving such as arriving and departing altitude, physiological effects and potential safety hazards, depth gauge and computer use, etc. If it is something you are planning to do (Lake Tahoe, Colorado, New Mexico, etc.), get the proper training. While Scuba Board is a great reference tool, it doesn't replace a Scuba Instructor.
JcF
PS - Remember your "flying after diving" rules (see back of tables). That applies to driving to altitude as well. It should properly read, "reaching altitude after diving" rules.
When you are away from the coast, like we are in Arizona, we have to accomodate for the increase in altitude where there's less air pressure. Thus Altitude Diving requires special table or computer procedures to account for the atmospheric pressure difference. While the decompression model difference is minimal at Lake Pleasant, it should not be ignored. Always follow the proper procedures, no matter how minimal the risk differential. Diving at altitude without following the proper altitude procedures increases the risk of decompression illness.
Without getting into the whole Altitude Diver Specialty Class:
Divers with computers make altitude adjustments by reviewing the owners manual. If their computer changes automatically, then no action is needed on their part. However, it has been my experience that computer altitude preferences need to be set. In the case of Suunto computers, they have an altitude setting of (A0, A1, A2, and A3). A0 is obviously sea level and A1-3 is a range setting. For Arizona, we use the A1 Setting which is calculated up to 3000 feet or 4000 feet (I don't exactly remember).
Divers with tables make altitude adjustments by planning their dive for a theoretical depth. Following is a link to a chart that was printed by Skin Diver Magazine that looks very similar to the one I use.
http://www.sandiasnorkel.com/info/inf-g_10.php
With this, you take your actual depth, convert it to a theoretical depth depending on your altitude, and plan your dive accordingly. Please note the difference for safety stops.
Lastly, there is a lot more covered in relation to Altitude Diving such as arriving and departing altitude, physiological effects and potential safety hazards, depth gauge and computer use, etc. If it is something you are planning to do (Lake Tahoe, Colorado, New Mexico, etc.), get the proper training. While Scuba Board is a great reference tool, it doesn't replace a Scuba Instructor.
JcF
PS - Remember your "flying after diving" rules (see back of tables). That applies to driving to altitude as well. It should properly read, "reaching altitude after diving" rules.
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