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Flying after 20ft dive

Discussion in 'Ask Dr. Decompression' started by anchochile, Sep 20, 2018.

  1. anchochile

    anchochile Barracuda

    # of Dives: 50 - 99
    Location: Northern California
    I'm headed to Florida for work soon and am hoping to fit in a dive at the Blue Heron Bridge. Depths on this dive range from 10-20 fsw and bottom time would be 1-2 hours.

    Based on the tides when I'm there, the dive would be in the morning around 8-9am.

    I'm wondering, given that it's such a shallow dive, how much offgassing time I'd need before flying. I could either fly out that same afternoon (with about 6 hours out of the water to offgas before the flight), or the following afternoon (with 30 hours of offgassing before my flight).

    Waiting till the next day means paying for an extra day for a rental car, an extra night in a hotel, and an extra 24 hours away from my family. But of course, none of that is worth getting bent over.

    I'm usually very conservative when it comes to avoiding DCS and don't have any interest in pushing my margin of safety, so my working assumption here is that if I do the morning BHB dive, I'd need to wait until the following afternoon to fly out.

    But I thought I'd pose the question here on the off chance that the experts would say that it's totally fine, given the shallow depth of the dive and minimal nitrogen that I'd absorb.

    Note: the day before the BHB dive, I will be diving in Key Largo, with my last dive ending mid-afternoon, about 24 hours before my theoretical flight. Not sure if this would make a difference.
  2. GetDownScuba

    GetDownScuba Instructor, Scuba

    # of Dives: 200 - 499
    Location: Virginia
    Multi-day, repetitive dives = 18 hours.
  3. scubadada

    scubadada Diver Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Philadelphia and Boynton Beach
    Good question. DAN guidelines do not help. Single, no deco dive has a 12 hour no fly time, no guidance on such a shallow dive. Maybe @Duke Dive Medicine can assist. How does the shallow dive fit into your previous series, which will 24 hours prior to your flight? Conservative thing to do would be to wait at least 18 h.

    I dive in SE FL frequently and more than occasionally have flown at 18 hour or a little longer after a long series of dives. I often have more like 24 hours. I have never felt inclined to push the guidelines
  4. EireDiver606

    EireDiver606 DIR Practitioner

    I don’t think it would matter too much after a 6m dive, but obviously don’t do it if you can avoid it.
  5. lv2dive

    lv2dive Formerly known as KatePNAtl Staff Member

    # of Dives: I'm a Fish!
    Location: Lake City, FL
    I am not suggesting you do this, but as a point of reference, I know quite a few people who dive in shallow Mexico cenotes and basically get on the plane with wet gear and hair.

    I think the current recommendations are 12-18 hours for a single dive and 18-24 hours for multiple dives. However there is certainly a subset of people who would get on a plane after the dives you describe; it depends on each person’s risk tolerance. If you are fairly conservative it probably makes sense to book the hotel for an extra night.

    chillyinCanada and northernone like this.
  6. runsongas

    runsongas Great White

    # of Dives: 500 - 999
    Location: California - Bay Area
    by the rdp, you are washed out after 6 hours if you don't venture deeper than 30 ft. with a rich nitrox mix like ean40 or above, probably safe enough.
  7. northernone

    northernone Great White Rest in Peace

    # of Dives: 1,000 - 2,499
    Location: Currently: Cozumel, from Canada
    It's a fuzzy zone, what's safe vs. safe enough.

    I've not found official recreational dive guidelines for handling shallow dives besides for treating hyperbaric exposure as hyperbaric exposure and using recreational dive recommendations as a safety margin.

    To avoid the issue I dive pure oxygen if I'm flying the same day. Just psychologically makes me feel better than risking a shallow air dive without clear medical guidelines within my training "clearing" me.

    lv2dive, hroark2112 and MichaelMc like this.
  8. Charles2

    Charles2 Manta Ray

    # of Dives: I just don't log dives
    Location: Montgomery, Texas
    The US Navy has tables for what you propose and there are limits, (20 feet for 2 hours will require a 7:06 surface interval before ascent to an altitude of 8000 feet); however, I would recommend that you follow your training.

    A very rich Nitrox mix will reduce that requirement.
  9. anchochile

    anchochile Barracuda

    # of Dives: 50 - 99
    Location: Northern California
    Thanks, all, for the opinions. Sounds like I'd probably be ok but not worth taking the risk. I'm going to go with my gut and my training and not fly the afternoon after this dive.
  10. Dirty-Dog

    Dirty-Dog Frequently Censored ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: Pueblo West, CO, USA
    I might do it, but I'd do the bridge dive on a high-octane mix. 80-90% O2 would work, if I couldn't get 100%.
    More likely I'd just book an extra night.

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