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Inflating a Six Footer

Discussion in 'Advanced Scuba Discussions' started by Ghattas, Jan 4, 2020.

  1. Ghattas

    Ghattas Angel Fish

    # of Dives: 100 - 199
    Location: Everywhere
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    Hello all,

    I recently bought a shiny new dsmb - 6 foot tall, closed, with oral inflation hose. I have yet to use it in the water but on a “dry run”, noticed that it takes at least two lungful of breaths to get the darn thing fully inflated. Question is, underwater, while inhaling from the reg to take that second requisite breath, I am quite sure I will turn positively buoyant with the half inflated dsmb. What are my options? Take the lp hose out of the wing and use it to inflate, returning it to position after being done with the inflation? I am however not too keen on fiddling with the lp hose in a tricky phase like deploying the dsmb, also taking into account the pain it takes to return it to position afterwards to overcome the positive pressure.

    Ideas would be welcome :) and yes, in retrospect, I would have bought a shorter one!
     
    Johnoly likes this.
  2. Norrm

    Norrm Banned

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    Dump some air out of your BCD before you orally inflate. Sure you'll descend a bit at first but with practice you'll get it just right.

    I agree with you that removing the LP hose from the BCD, inflating the SMB and then reattaching it to the BCD while under pressure and holding a reel and inflated SMB can be rather tricky- I'd never attempt it when there are better options.
     
    Ghattas likes this.
  3. JackD342

    JackD342 Dive Shop

    # of Dives: 500 - 999
    Location: Highland Park, IL
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    How deep are you when you are deploying the DSMB? The air will expand on the way up. Half full at 33 ft becomes full at the surface. Half full any deeper and it will be dumping air from the over pressure valve on the way up, assuming it has one. If not, you need to think harder and act carefully.
     
  4. Ghattas

    Ghattas Angel Fish

    # of Dives: 100 - 199
    Location: Everywhere
    30
    9
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    Good point. Often at 20 feet, so has to be slightly more than half full.
     
    Johnoly likes this.
  5. JackD342

    JackD342 Dive Shop

    # of Dives: 500 - 999
    Location: Highland Park, IL
    2,514
    1,499
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    Plenty to get it up and deployed. You can top it off at the surface if need be.
     
    Johnoly likes this.
  6. Diver below 83

    Diver below 83 Regular of the Pub

    # of Dives: I'm a Fish!
    Location: SoFlo
    1,146
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    Practice makes perfect with dsmb’s
     
    Johnoly likes this.
  7. PfcAJ

    PfcAJ Orca

    # of Dives: 5,000 - ∞
    Location: St Petersburg, Fl
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    I use the BC inflator hose in big boi SMBs like that.
     
  8. mcpowell

    mcpowell Barracuda

    # of Dives: 100 - 199
    Location: Georgia
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    If you have air in your BC, you can dump the BC air into your DSMB first. You’ll be negative, but your DSMB will be equally positive and the net effect should be neutral (assuming you were neutral before you started the process). Then, if you need to add more air to your DSMB go ahead. Try to have an idea what percentage of full your DSMB should be so that it’s 100% full at the surface. No need to fill it all the way at depth.

    Practice.
     
  9. Alekseolsen

    Alekseolsen Angel Fish

    # of Dives: 50 - 99
    Location: Norway
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    If the BC fits, doesn't the octopus fit??
     
  10. KWS

    KWS ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: SE TEXAS
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    Keep in mind that you do not have to fully inflate the buoy. take into account the expansion of the gas you put into it. At 33 ft you have ti fill it half way at 66 ft you have to fill it 1/3 full and at 100 ft you have to fill it 1/4 full and let it go. air will expand and will be full at the surface. It is difficult to inflate one in shallow water because in the case of doing it at 33 ft 1/2 the volumn is still a large lifting volumn of air. Imagine a 8 ft 8' diameter buoy. if you can connect an additional lp hose and put a fill nozzle on it you can fill using that or directly form the lp hose on the oral fill tube. the fill will be faster and you can get the required gas int he buoy before it starts up to the surface. Its no easy task. to find a buoy that fits your need it often becomes a bear to fill.

    Shoot your buoy deep and then reclaim the line to the depth you need to be at. also at SAY 20 FEET ON THE LINE TIE A KNOT FOR A PHYSICAL REFERENCE TO THE DEPTH
     
    Soloist and Johnoly like this.

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