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Dive Computer vs Bottom Timer vs watch

Discussion in 'Computers, Gauges, Watches and Analyzers' started by boney, Apr 16, 2004.

  1. IndigoBlue

    IndigoBlue Manta Ray

    That sounds more encouraging to me than would be pushing the 1.6 PO2 limit.

    NAUI RGBM Deco Tables reflect an NDL time of 6 mins for a 45 meter dive, like when you are "try[ing] to be good." The USN tables reflect 5 mins of NDL time for that depth. The two somewhat agree.

    The more salient question is at what depth should your first 1 min deep stop be during your return? Most would say around half your MOD, which comes to about 75 ft.

    Paradoxically, however, the RGBM Deco Tables show no need for a required deep stop on a dive to 45 meters if it is 10 mins or less (however a 2 min 10 ft deco stop on oxygen would be required). For such a dive for 15 mins, the first deep stop is at 30 ft, and for such a dive for 20 mins, the first deep stop is at 50 ft (all followed by oxygen deco). These first deep stops are 1 min stops. The USN tables do not reflect these deeper stops, and so the USN tables may be too aggressive.

    For any diving to 45 meters or more, for a duration of longer than 6 mins, you would need to consult the USN dive tables for your required deco stops, however, since RGBM uses oxygen on the 20 and 10 ft deco stops for an air dive to 45 meters when longer than 6 mins.

    That is what you are up against, when you venture to those depths.

    If you stick to the traditional 130 ft recreational MOD, then your RGBM NDL time limit is 10 mins, and for such a dive, no deep stop is reflected on the RGBM deco table. That would be most divers' recommendation as well. My own recommendation is 100 ft, max. And when I dive to 100 ft, I stop at 50 ft for 1 min, 25 ft for another 1 min, and 15 ft for 3 mins.

    Dive safe, and "be good." :)
  2. armyscuba

    armyscuba Barracuda

    I agree with you and always do additional stops. That is one of the benefits of Diving everyday. You stay current with Your abilities and practice emergency procedures. Even diving an AL100 I practice My Thirds Rule. We have a staged bottle at 15 ft. on Boat dives. Oxygen in the Truck...You need not worry about Me exceeding My abilities..just for this deployment I'm on Dive #406 Today..It was a nice day..82 degrees at 77 ft. See, I was very good..
  3. boney

    boney Barracuda

    # of Dives: 50 - 99
    Location: Toronto, ONT, Canada
    Thanks everyone for your responses.
    When I first started a while ago I used a simple bezel watch and now that I'm getting back into diving I was looking at getting something with more features. I like the computers as my buddy has one and I like the profiles and planning features on some of them, plus the added bonus of Nitrox compatibility, but it may be overkill. I have yet to take a Nitrox class... The prices that you guys mention must all be in USD. I got those prices from the several LDS's I visit here in Canada.
    I may just get a bottom timer for now and then upgrade to a Sunnto later on and use the timer as a backup...

    Thanks again!!!
  4. stargost

    stargost DIR Practitioner

    if you are in Canada, buy local ;-)

    Liquivision : Scuba : Xen


    More seriously, get a computer ! Almost all have a gauge mode anyway.
    To be really useful, a BT is good if you can get average depth calculated for you (for stupid people like me, it is easier), and also a real timer which give you second.

    uwatec aladin/tec 2G or sub-gear xp (same thing) should give you that. They are a bit ugly though. I think several other brand can provide decent gauge mode with timer in less than 300$, but it may be a stretch new.
  5. bergersau

    bergersau Solo Diver

    # of Dives: I just don't log dives
    Location: Melbourne Australia

    10 Year old thread...
  6. Agility

    Agility Solo Diver

    # of Dives: 200 - 499
    Location: Austria
    that shows that stargost knows how to use the search function :wink:
    koozemani likes this.

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