Questions on Altitude Diving.

[OregonRich]

I'm a newer diver and much of my diving will be in local lakes (ranging in elevation from 3000ft to 5000ft.) I've checked the web & found two different tables for altitude diving. They seem easy enough to use, but I would appreciate any other tips I should consider. Thanks.

 

[pt40fathoms]

That the Altitude Diving specialty course. It's one thing to say the Altitude Diving is different than diving at or near sea level, it's another thing to learn this lesson while in a chamber.

Knowledge is power, and in this case it will keep you happy and safe as well.

 

[Fishlips_1]

Waldo lake is AWESOME!! Check your pm's. Go to user cp

 

[Fishlips_1]

Diving Crater in Sept. that will be WAY BAD!!!! I mean good.
Lips

 

[Tod]

Depending upon which chart you pick, be careful as not all agencies use the same number of letters in their tables. For example, some tables only use A through L for their pressure groups, while others may use A through W or more. So the difference jumping from one group to the next may not be what you're used to if you use a different agency's table. Not that you can't use the other agency's tables, but just be aware of this.

Another thing that I've seen overlooked before is while you can figure out how long you need to off-gas before going diving after driving UP to a lake, don't forget that you may need to off-gas before driving back home if you need to go over a higher altitude pass to get back home!

The best suggestion, as stated above, is to get some training from an instructor. It's not that complicated but there are a few things you'll need to be aware of for your safety.

Enjoy the lakes!

 

[Fishlips_1]

I have a couple articles that I could scan and email you. Not sure how to attach to a thread.
Lips

 

[JS1scuba]

I'm a newer diver and much of my diving will be in local lakes (ranging in elevation from 3000ft to 5000ft.) I've checked the web & found two different tables for altitude diving. They seem easy enough to use, but I would appreciate any other tips I should consider. Thanks.

Most quality dive computers will automaticaly adjust the no-stop times when activated at altitude. Expect that you will have a shorter no-stop time at that elevation.

One method we use for altitude diving is to use nitrox 36% up to 5000 foot elevation and fly an air table or air computer. The decreased nitrogen in that mixture compensates for the altitude (kind of line reverse MOD)

As a new diver you should invest in a quality nitrox capable dive computer (Cobra, Vyper, Vytec) and take a good nitrox class and read up on diving at altitude in the NOAA Diving Manual 4th Ed.

Regards,

 

[OregonRich]

Thanks for the responses. As far as taking a class, I spoke briefly with an instructor and he said one wasn't needed (and actually, that his shop didn't even offer one.) My main concerns revolve around the "wait time" needed after arriving at the lake before diving & the "wait time" needed before departing from the lake after diving. I'll check the NOAA manual, but if anyone has other information I'd appreciate it.

Rich

 

[pt40fathoms]

Thanks for the responses. As far as taking a class, I spoke briefly with an instructor and he said one wasn't needed (and actually, that his shop didn't even offer one.)
Rich

Well, if they don't offer the class, then how on earth can they make an informed response to your question of whether you need the class? Sounds to me more like "we can't teach you this class, so we'll just tell you you don't need it".

The course covers a multitude of items, and offers you the added benefit of practicing what you have learned in a controlled supervised environment. My advice is to seek out a shop or instructor who is qualified to teach the course and ask him/her about the course. Not all instructors are qualified to teach this specialty, and if you are in an area that involves altitude diving, you should at least get the opinion from a qualified instructor.

 

[DA Aquamaster]

You can dive regular air and nitrox tables at altitude using the Cross corrections.

This essentially uses a chart to find the theoretical depth for a given altitude and also uses a rule to determine your repetective group on arrival at altitude if ascending to the dive site. A variant of this is to use a capilary depth gauge (if you can still find one) as it will give you theoretical depth underwater at altitude automatically.

A more common apporach however is to use a computer designed to accommodate altitude diving.

Table wise, the Buehlman tables are the only ones I know of that were developed specifically for altitude diving.

I would not go so far to say a class is required, but at a minimum you need to do a lot of self study, be very well read on the subject and be very comfortable with the theory involved to safely do it. (In fact I'd suggest that apporach is desireable even if you have taken a class a specialty class on altitude diving can be pretty minimal in terms of actually covering all the relavent information.)