Mailing List Archive Mailing List Archive
-----Original Message----- From: George Irvine [mailto:girvine@be*.ne*] Sent: Sunday, January 06, 2002 6:32 PM To: Miranda Alldritt; Quest@Gu*. Com Subject: RE: Decompression - Questions on Repetitive Dives This area of the discussion needs to be prefaced by a couple of important reminders. One, keep in mind what I said about the level of offgassing in bubble form when the move is made to 1 ATA at the surface - this can be a real shower of bubbles if you do not follow the ascent recommendations that I made. Be that as it may, the other important point is the bubbles tend to GROW post dive as they take like gas in from around them. They peak in size and then diminish. This is all relative. If you look at decompression folklore, like what IANTD teaches, you will see references to bubbles peaking in size and frequency up to four hours after a dive. First of all, this applies more to people who should not be diving in the first place, and secondly it applies to air diving where there is no adequate way to decompress. In my case, I totally clear of any signs of bubbles from the most horrendous dives in 30 minutes or less. That is what you should shoot for , but more importantly, shoot for no bubbles to start with by following my final ascent guidelines. Bubble growth is fact life. Showering bubbles post dive is a screwup. As far as "residual nitrogen" or helium or whatever, this is total bullshit. It is inherently more true for nitrogen since we are full of it anyway, but the fact is the only consideration you have to give to repets is in the concept of ascent once you have taken a surface interval and may be still bubbling - you have to be far more careful about your ascent rate on a second dive due to this effect. See my post on "why we do not bounce dive" for all the reasons. Otherwise, repetitive diving is a good thing, and you should do your shallower dive first and then your deeper one. The stupidity taught in that regard is beyond the pale. -----Original Message----- From: Miranda Alldritt [mailto:miranda@pa*.co*] Sent: Thursday, January 03, 2002 1:18 AM To: trey@ne*.co* Subject: Decompression - Questions on Repetitive Dives Hi George, Thanks for the great discussion so far. I read your earlier post on repetitive 150 dives but there are some things I still don't quite get. Would you mind going into repetitive dive planning in a little more depth? How do you account for various surface intervals and what are your guidelines for what's reasonable in terms of multiple dives in a day? As an example to look at, can you tell me how you would plan for 2 dives to 200ft for 30 minutes each with various surface intervals? When I look at this in DecoPlanner, even with an SI of 3 hours, I get a really long O2 stop for the second dive. Is that a reality? Also, nothing else in the deco seems to really change? Thanks in advance, Miranda -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]