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Beginning of my Tech Diver adventure

Discussion in 'Rocky Mountain Region' started by Waterskier1, Sep 2, 2008.

  1. b1gcountry

    b1gcountry Divemaster

    # of Dives:
    Location: Middle
    1,691
    16
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    BTW, I'm pretty sure the Sherwood Magnum second stage is not balanced.

    Tom
     
  2. Waterskier1

    Waterskier1 Divemaster

    # of Dives: 200 - 499
    Location: Colorado Springs, CO
    868
    8
    0
    I'm pretty sure you are right. The first state is balanced, but I think the new SR1 is the only balanced second stage that Sherwood makes.
     
  3. georoc01

    georoc01 Manta Ray

    # of Dives: 200 - 499
    Location: Denver, Colorado
    857
    7
    0
    I have my rig pretty much put together now. Got the tanks VIPed, so I am ready to go. Just need to find a place to try them out!
     
  4. b1gcountry

    b1gcountry Divemaster

    # of Dives:
    Location: Middle
    1,691
    16
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    For the record. I spent 65minutes in water early this spring on Lake Michigan in 38* water. No Thermocline. I was toasty warm at the end of my dive. No argon.

    Tom
     
  5. jerryn

    jerryn Nassau Grouper

    # of Dives:
    Location: Divide Colorado
    173
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    This is a good thread ferreting out some of the aspects of tech diving. I have been doing this for some time and want to comment on computers and dry suits.

    First, most tech divers use bottom timers rather than computers. Even though computers can do a lot, what they cannot do is a. plan your dive and your gas requirements. You have to do that before getting in the water. That is the technical part of tech diving. So regardless of your computer, you already have your deco set before you go diving. Moreover, computers fail and dives go bad. In either case you need to know how to get to the surface successfully. Suppose you are at 180' on a dark wreck and you get snagged on some monofiliment. You end up starting your ascent at 35 minutes rather than 25 minutes because you had to solve the problem. Your computer fails -- what do you do? The answer is simple, you already know because you cut tables and studied them and understand the deco that is right for your physiology. So it might be cool to wear a $1600 dollar computer, and it might give you some piece of mind, or something to do on deco==mine makes smiley faces at me which is fun==but they are neither needed nor used very much in tech diving.

    Dry suits: When you are doing deco you are not moving around very much. It is easy to get cold. I did a week long trip to the South China Sea...toasty warm at 82 degrees. But 90 minutes at 82 (it is less than 98.6) in a current is enough to make you cold. Being tough and able to withstand the cold is not the point. When your body gets cold, your circulation slows down, especially in the extremities. It is this circulation which moves gas coming out of solution form to your lungs for respiration. So cold is the enemy of decompression. Sorry, you don't need a computer but you sure need a dry suit unless all of your tech diving is going to be at 85 degrees or warmer and your deco an hour or less.

    One really important aspect of tech diving, never discuss your purchases with your spouse or children. I remember a conversation at the table one night which went something like "you spent how much on a flashlight?" and went downhill from there.

    Have fun diving

    Jerry
     
  6. b1gcountry

    b1gcountry Divemaster

    # of Dives:
    Location: Middle
    1,691
    16
    0
    Wow, I had the same conversation. Although once she got to dive with the light she didn't complain any more.

    Tom
     
  7. RiverRat

    RiverRat Instructor, Scuba

    # of Dives: 200 - 499
    Location: Connecticut
    1,487
    14
    38

    Yep I agree totally. I'm currently doing 25 - 35 min. bottom times on wrecks in the 110-130 fsw range and I'm learning a TON of stuff on these dives. I've already been exposed to several "failure modes", not just mine, but my buddies and other divers/teams in the group. While nothing is guaranteed 100%, if you plan properly you should be able to deal with most "gotchas" effectively. I think these depths and times are perfect to get yourself sqaured away and get used to longer hang times. If you do screw up you have a better chance of getting out of it ok, provided you have a decent backup plan, lost gas, buddy etc. As my instructor stated, the margin for error starts to shrink rapidly as you get into mixed gas, deeper depths and longer bottom times. You don't work out the bugs on those dives. You work it out on the "easier" dives. Get your gear in order, practice longer hangs, switching to your deco bottle, and practice, practice, practice until these dives are routine. Then you can move up.
    Just my O2 cents :)
     
  8. georoc01

    georoc01 Manta Ray

    # of Dives: 200 - 499
    Location: Denver, Colorado
    857
    7
    0
    Don't bottom timers also have batteries that can fail? I have never understood this argument against computers, just upon depending on a single computer for your life.

    What started this thread is talking about the differences in equipment between what would be considered recreational diving vs tech diving. Since I see most of my diving on the rec side, I would like a flexible setup that would allow me to use it for both, and when you are doing multiple multi level dives over many days, a computer is still a piece of your equipment you need to use. Many dive boats even require it. However, redundancy also needs to be part of the setup as like is stated above, computers can fail for a variety of reasons.

    The fact is that in the Rockies, there are very few opportunities to do dive local, and for tech diving, even less. So most of my diving involves travel and flexiblity is a must.
     
  9. amascuba

    amascuba Instructor, Scuba

    # of Dives: 500 - 999
    Location: Austin, TX
    2,246
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    Computers vs. Bottom Timers:

    They both provide the same fundamental information: Run time, max/current depth

    Bottom timers are more flexible in application as they don't limit which gases that you use or decompression algorith that you use.

    Computers are more convenient in that they calculate everything for you, but at that same time they encourage complacency doing so by limiting the knowledge needed of decompression theory/tables for the dives. Say a computer dies mid dive and you notice it only when you happened to glance at it. How long have you been down? What's your max/average/current depth? What strategy do you use to get out of the water safely? What if you forget to set the computer to the gas you are using?

    With a properly planned technical dive, a bottom timer, a backup (or in some cases, your buddy is your backup) you most likely already have that information memorized in your head or in wet notes. Same plan, with a computer and a backup computer. Are you going to run the dive or are you going to let the computer run your dive? If you are going to run the dive, what do you do when you bend your computer and it locks you out from diving the rest of the day? What if your using two different computers that use different algorithms? Which one do you follow? Do you ignore them both and just follow your own plan? What if the computer doesn't have a setting for a gas that you want to use?

    For multi-level dives, depth averaging can be done easily. I've done it on liveaboards doing 5 dives a day with an average of 60 minute bottom times. It just takes a little awareness.

    Also, price is a big factor for a computer that can run technical dives. Do you really want to pay upwards of $1700 for a computer that will limit which gases you use, how many different gases that you use, and your algorithm? A basic bottom timer will cost you $200 for basic features (max depth, current depth, run time, water temp, and log 9 dives) and a more advanced one will run around $475 (max depth, current depth, average depth, run time, stop watch, backlit, log 24 hours of dives, and computer downloadable log).

    In the end I find that bottom timers are more flexible than computers.

    Also for more flexibility. I use the same gear for recreational single tank dives as I do for doubles. The only thing that changes are exposure protection and the wing that I use.
     
  10. Waterskier1

    Waterskier1 Divemaster

    # of Dives: 200 - 499
    Location: Colorado Springs, CO
    868
    8
    0
    James, thanks for the information.

    Until I started reading some of the posts on here, I didn't even realize there were computers in the $2000 range that didn't include the rebreather also :D

    My original point was to let people who might venture into tech diving to be aware so they might buy equimpment that can make the journey with them. When I bought my computer, I didn't get a console mount because at the time I didn't think I'd even own my own regs. I didn't think I'd ever use a bottom timer and thought that was only used when you locked out your computer. :shocked2:

    Regarding computers, I would suggest, based upon my limited exposure to Tech diving, that you get a wrist mount, and that it have the option of being used in gague mode. Also, you might want to check that it will work to the depth that you think you'll be diving. I also am glad that mine had NITROX, even though I had no intentions of diving NITROX when I bought it.

    I guess these comments are addressed to NOOBs like I was, since all the experts already know what they need. But this discussion is great, and I'm learning a lot. :lotsalove:
     

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