• 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

Dive knife, Sea Snips, or both?

Discussion in 'Knives and Cutting Tools' started by briannapstevens, Sep 13, 2017.

  1. Skulmoski

    Skulmoski Barracuda

    # of Dives: 100 - 199
    Location: Gold Coast, QLD
    381
    159
    43
    I carry titanium snips (right side BP/W belt), Spyderco Enuff Sheepfoot in H-1 steel (left side BP/W belt), and Hollis titanium line cutter on left BP/W shoulder strap). Different cutters for different jobs. And redundancy if i loose a tool or get tangled and cannot reach a primary tool.

    GJS
     
    briannapstevens likes this.
  2. Trace Wilson

    Trace Wilson Angel Fish

    # of Dives: 25 - 49
    Location: Florida
    29
    5
    3
    Curious, any idea how fast do you lose air from a tank if the high pressure hose goes, i.e. PSI/min? Just wondering how long I'd have to get topside if I lost one.
     
  3. Dan

    Dan Orca

    # of Dives: 500 - 999
    Location: Lake Jackson, Texas
    5,537
    3,084
    113
    No clue. Sorry. That's why we have buddy system in addition to the gear redundancy to make sure we cover screw up resolutions as much as possible.
     
  4. Lorenzoid

    Lorenzoid idling in neutral buoyancy

    # of Dives: I just don't log dives
    Location: Atlanta, USA
    9,066
    5,567
    113
    I love this video, comparing how long it takes to drain a tank if a diver's HP hose is cut with how long it takes to drain a tank if the diver's LP hose is cut:

     
    Saboteur and Trace Wilson like this.
  5. Dan

    Dan Orca

    # of Dives: 500 - 999
    Location: Lake Jackson, Texas
    5,537
    3,084
    113
    You got me curious about doing the math now :)

    It'll be about 7.5 minutes according to the following input data, calculations & assumptions:
    Tank size: AL80 or 80 CF
    Initial pressure = 3185 psig (max input for the Engineering Calculator allowed for calculating an air flow through orifice (I assume it reaches the sonic velocity): Calculator: Air Flow Rate through an Orifice | TLV - A Steam Specialist Company (International)
    Air temperature = warm water temp of 82F
    Hose inside diameter = 1/4"

    IMG_6361.PNG

    The gas rate is estimated to be 2301 SCFM. The AL80 at 3185 psig will have 17333 SCF (3185 x 80 / 14.7). Leak time = 17333 / 2301 = 7.5 min.
     
  6. Charles2

    Charles2 Manta Ray

    # of Dives: I just don't log dives
    Location: Montgomery, Texas
    523
    317
    63
    I think you are waaaay off on this one. Hose may be 1/4" ID but orifice is much, much smaller. An AL80 at 3185 psi will have about 82 SCF. Also, the tank pressure will not be constant but decreasing as the air bleeds out.
     
  7. briannapstevens

    briannapstevens Angel Fish

    # of Dives: 100 - 199
    Location: United States
    44
    3
    8
    Don't take it personally! :) I'm just jealous! I keep fantasizing about the Suuntos. But cannot afford one! I have two computers, too. Crappy old Oceanic ones, although I still love my Veo. I really want an air integrated computer w/digital compass!
     
  8. Dan

    Dan Orca

    # of Dives: 500 - 999
    Location: Lake Jackson, Texas
    5,537
    3,084
    113
    You are right! :) I forgot about the tiny orifice at the fitting to the 1st stage & the tank losing pressure. The low pressure hose will actually lose air faster due to the larger orifice. Live & learn. Thanks for the tips :)
     
  9. Dan

    Dan Orca

    # of Dives: 500 - 999
    Location: Lake Jackson, Texas
    5,537
    3,084
    113
    That's a very educational video! Thanks for posting :)
     
  10. Dan

    Dan Orca

    # of Dives: 500 - 999
    Location: Lake Jackson, Texas
    5,537
    3,084
    113
    None taken :)

    Just wanted to share my past experience on the importance of having redundancy.
     

Share This Page