• Welcome to ScubaBoard

  1. Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

    Benefits of registering include

    • Ability to post and comment on topics and discussions.
    • A Free photo gallery to share your dive photos with the world.
    • You can make this box go away

    Joining is quick and easy. Login or Register now by clicking on the button

tank size for AN/DP

Discussion in 'Technical Diving Specialties' started by gbray, Jun 18, 2011.

  1. gbray

    gbray Nassau Grouper

    # of Dives: 100 - 199
    Location: warrenton,missouri
    183
    15
    18
    One of my dive buddies is an independant instructor. I have just began to DMC with him. We both dive similar gear, BP/W with long hose etc. and both dive doubles (except when doing ow class). I have two sets of doubles, LP72 and HP 80. I really don't care for the hp80's much because I have trim issues with them. I really like the lp 72's. My buddy really wants me to take the TDI ANDP class with him in two months. I have been wanting to get a set of LP85's or 95's to replace my 72's and use that for the class. My question is will the 72's be suffecient for the deco portion of the class?
     
  2. japan-diver

    japan-diver Dive Charter

    # of Dives: I'm a Fish!
    Location: Okinawa, Japan
    1,483
    192
    63
    Ask the instructor you are taking the class with. Where and how long are the dives he/she is planning for the class and what is your RMV will answer this question.
     
  3. aquaregia

    aquaregia NAUI Instructor

    # of Dives: 500 - 999
    Location: Santa Cruz, CA
    1,953
    185
    63
    I really wish that the tech agencies would post their procedures online. I understand the liability of doing so, but it would allow me to make tank purchases understanding ramifications that might come up in the future.

    People seem to take AN/DP in AL80s, which have the same volume as a modestly overpressured (2700psi) set of 72s.
     
  4. japan-diver

    japan-diver Dive Charter

    # of Dives: I'm a Fish!
    Location: Okinawa, Japan
    1,483
    192
    63
    The procedures and dives for most agencies are available on line. For courses your best bet is to talk to your instructor- I teach tech but the conditions here are different then elsewhere, also each student and dive team has different needs - a good instructor will be able to guide you and your team to make the right purchasing decisions. If the instructor you choose to train with can not answer these questions find a different instructor.
     
  5. RTee

    RTee Divemaster

    # of Dives: 500 - 999
    Location: Ottawa, ON
    1,248
    152
    63
    Very interesting question and comments. I think it is up to you to decide what you are really after...if you have a good idea of what your SAC/RMV is and why you want to take such a course, then it should be pretty easy to figure out what size tanks you should be looking at. Around here, 2 X 100 cft set-up (minimum) seems to be the standard. I opted for 2 X 117 cft when I bought my double set. Next choice wil be between LP and HP... I would not necessarily buy the tanks just for the course but what I intend to use them for once the course is completed. If in doubt, you may want to rent the set-up for the course and then buy what you really want once you have more info.
     
  6. txapacheguy

    txapacheguy Solo Diver

    # of Dives: 50 - 99
    Location: Colorado
    168
    7
    0
    When I took this same course a few months ago, we used what we had on hand between myself, the instructor, and the other guy taking the class. The instructor had a set of double 72's. I had a set of HP98's. The other guy was using double AL80's from the shop. I think we all used the extra AL80's from the shop for our last day of diving... No one had any issues with this configuration.

    I did run my AL30 with EAN 50 a bit short when we did a post-deco swim around Rock Lake. Like I said though, our deco was complete, I did end up completing the dive on my stage with no issues, and I had plenty of back gas left. An AL40 and stage rigging for one of my 80's is on my shopping list prior to my next set of deep dives.
     
  7. RTee

    RTee Divemaster

    # of Dives: 500 - 999
    Location: Ottawa, ON
    1,248
    152
    63
    When I took mine, my instructor recommended...perhaps insisted would be a better word, that beside my set of doubles, I show up with two stage bottles...a 40cft (100 O2) and an 80 cft (32 to higher O2%). Therefore my entire course was conducted with doubles on my back and slinging two stage bottles.
     
  8. Garth

    Garth Manta Ray

    # of Dives: 200 - 499
    Location: North Carolina USA
    1,047
    136
    63
    Interesting. Much of the beginning dives for me had my al40 and my doubles with air and simulated deco. I thought it was helpful when he handed me his steel45.... What a difference.
     
  9. txapacheguy

    txapacheguy Solo Diver

    # of Dives: 50 - 99
    Location: Colorado
    168
    7
    0

    That makes sense. I have three sets of doubles in the garage now (enough for the trimix class hopefully), so getting a few of the right stages set up before my next class is a priority now. The shop had a ton of old steel 45's (or something similar)for our deco gas, but I was not a fan of them. I'm thinking either a Luxfer40 for EAN 50 and my AL30 for 100%, or I will put EAN 50 in one of my Luxfer80's and 100% in my new 40 like you mentioned (that seems like a pretty clean way to keep plenty of deco gas on hand.)

    Ultimately, I will defer to the instructor's recommendation, but thus far he has given us room to make a lot of our own equipment decisions, and to use the resources available to us as long as we are safe.
     
  10. rongoodman

    rongoodman ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Albany, NY
    3,506
    735
    113
    Another thing to consider about the doubles is where you're going to use them. More gas is nice, but there's a big difference between walking a little ways down a path from the picnic table to the spring, as opposed to climbing up the side of a rocking boat with them. LP 85s are about as big as I want on my back on a ladder, since I'm not that big--if I need more bottom gas, I'll carry a stage.
     

Share This Page