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New Diver: 3000' Altitude dive as first post certification dive?

Discussion in 'Basic Scuba Discussions' started by filmguy123, Aug 10, 2016.

  1. filmguy123

    filmguy123 Professional Photographer

    # of Dives: 0 - 24
    Location: Pacific Northwest
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    I have an OWW under my belt. I did well.

    Wondering about doing a group trip with a number of instructors and DMs to a 3000' altitude dive for a weekend trip next weekend (10 days from now). It sounds like a great and responsible/knowledgeable group going.

    It would also be my first actual diving post course.

    In addition, I would be switching from BC jacket and wetsuit to BP/W and drysuit for this next weekend in 10 days. In the interim, I would go to a pool to dial in my BP/W settings in board shorts in the pool. Then I would be taking my drysuit cert in the pool. And then I would be doing 2x check out dives my drysuit before this dive. However, the checkout dives would be at elevation also - 1500' - on the way to the altitude lake the group is diving.

    So basically, OWW, 3 pool dives (1x BP/W focused, 2x Drysuit + BP/W focused with private instructor, 2x 1500' elevation dives with drysuit for checkout dives, and then the weekend diving trip for the 3000' altitude dives).

    Any red flags about this? I understand the margin for error is less with altitude dives. I understand I am new with very limited experience. I understand I would be adding drysuit into the mix, as well as BP/W. On the other hand, I am with a good group of instructors and DMs to help guide me, and would be preparing as best as possible in the week preceding with training, etc. and felt pretty comfortable at OW.

    What say ye? I'd love to do the trip, it would be a great experience, great people, and great diving (certainly better visibility than anything else up here in PNW) and I am anxious to get out there! On the other hand, safety first.

    I would be diving in a USIA Techniflex drysuit, DSS SS backplate w/35lbs Taurus wing, Hollis F1 fins, Apeks XTX50/DST regs, Shearwater Perdix which as I understand compensates automatically for altitude (I would also do my homework on altitude diving beforehand, and request to work with the knowledge portion of this with my drysuit instructor).

    Opinions, wisdom, reality checks, insights... GO! :wink:I am open to whatever. I want to have fun, but I want to be safe.
     
    Last edited: Aug 10, 2016
  2. BreeAbyss

    BreeAbyss Nassau Grouper

    # of Dives: 200 - 499
    Location: Canada
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    I got certified at 3400ft and since I live at about 2000ft most of my dives are >2000 Change your computer setting to fresh water :) enjoy! Mountain lakes can be beautiful dives. Others might have more safety wisdom than me but it sounds like you are already aware of the differences in altitude diving
     
  3. nadwidny

    nadwidny Instructor, Scuba

    # of Dives: I just don't log dives
    Location: Cranbrook, BC
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    Don't worry about the altitude. It is inconsequential to everything else that will be going one.
     
    Hawkwood likes this.
  4. filmguy123

    filmguy123 Professional Photographer

    # of Dives: 0 - 24
    Location: Pacific Northwest
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    AFAIK from reading the manual, the Perdix auto adjusts for Altitude and I can easily swap salinity to fresh.

    Main concern was just any possible task loading combined with more severe consequences at altitude for any loss of buoyancy control in my first set of real dry suit dives, with only 1x OW weekend under my belt.

    But if it's all good... awesome! (I will admit I am glad to hear "don't worry about it" because I really want to go! Just want to make sure I am being smart :wink:)
     
  5. KevinNM

    KevinNM DIR Practitioner

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    Basically, don't be in huge hurry to leave if you are going to go to a higher altitude on the way home. People have gotten bent driving home from Santa Rosa, as you end up going up a few thousand feet pretty much any way you go. But for OW type diving this isn't a big problem if you don't jump out of the water and drive like mad to altitude. We typically kill a few hours after diving packing the gear up and eating at a restaurant before leaving and I haven't heard of anyone other than deep tech divers having issues over the last 5 plus years.
     
  6. filmguy123

    filmguy123 Professional Photographer

    # of Dives: 0 - 24
    Location: Pacific Northwest
    177
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    Cool! Yeah we are spending the night there in cabins on the lake. And I believe it's all downhill on the way home - as we go through the mountain pass it might incline up a little at one point +1000' but I am not sure, except to say, it's an overall downhill drive following the terrain and I live in the valley. But that SHOULD be the next day we depart for home.

    And if we did diving in the morning, it looks like I could take a 40 minute longer way to get a clean downhill the entire way by coming out of the area on a different road that doesn't follow the terrain up. But not sure if that's worth it to avoid the +1000 foot inclination (3000' to 4000' drive home on one road)
     
  7. DoubleAA

    DoubleAA Nassau Grouper

    # of Dives: 200 - 499
    Location: NC, US
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    Why is this required? The decompression algorithm on the computer is by the pressure, not depth. A dive computer tracks pressure and translates that based on a density of the water to a displayed depth. This calculated depth has no bearing on decompression. I never change the salinity setting on my computer as the difference in depth is negligible to me. On a normal recreational, shallow dive the difference is going to less than a couple feet.

    Here is a good reference from shearwater: FAQ and Support | Shearwater Dive Computers
    Click: Why does the depth reading on my Perdix disagree with my other computer?
     
  8. BreeAbyss

    BreeAbyss Nassau Grouper

    # of Dives: 200 - 499
    Location: Canada
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    I know it's not going to make a big difference and I know how my computer calculates it. No it's not necessary for the type of dives it sounds like he is doing.
    Filmguy123 appears to be very detail and number oriented and is concerned with making sure everything is squared away for every aspect of his diving, based on all his posts, so I believe my advice was good specifically for him. I have a couple diving friends who sound like him and I would bet money they always change their settings.
     
  9. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
    25,862
    17,526
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    It does adjust the altitude automatically, and it is indeed very easy to to change the salinity.

    It will take care of your decompression just fine, but it will not give you an accurate depth reading. The same is true of altitude. Before they made a change to the firmware, Shearwater computers would always start with an assumption of sea level until they were turned on and read the pressure to change the altitude. that means if you started the dive with the computer turned off and let it turn itself on with water contact, it would think it was at sea level throughout the dive. At the altitude at which I do most of my diving, the depth reading difference would be 5 feet or more.
     
  10. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
    25,862
    17,526
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    I agree with those who say not to worry about the altitude. It will not make a huge difference in your dive. If you were diving the PADI tables, you would be told to calculate two pressure groups for every thousand feet of increased altitude upon your arrival and plan your dive accordingly. If you are just over 3,000 feet, you would round up to 4,000 feet and thus arrive at the dive site in the H pressure group, which means your first dive would be like a second dive if you did it at that point. Of course, you are at that altitude in the car prior to arrival, and you will take a while to get set up for the dive. If that takes you 2 hours, you are in the A pressure group--close to starting from scratch.

    You are going to go to 1,500 feet first and do checkout dives. That barely counts. After you are acclimated to that altitude, you will make another small ascent. Again, that will barely count.

    Most people do not realize this, but buoyancy becomes more and more difficult to manage as you ascend in altitude, but at 3,000 feet it will not be noticeable.
     

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