1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Buddy commando and the mini cylinder

Discussion in 'Dive Equipment' started by Pothole, May 10, 2017.

  1. Dave Whitlow

    Dave Whitlow Well-Known Member

    Joined:
    Oct 27, 2010
    Messages:
    1,063
    Likes Received:
    393
    The maths concluded the bottle is too small. The bottle is adequate for purpose.
     
  2. jb2cool

    jb2cool Moderator
    Staff Member

    Joined:
    Jan 20, 2008
    Messages:
    3,150
    Likes Received:
    481
    That's what was confusing me. The bottle must surely be fine (Even if it has to be full to 200bar) but I can't see how. Unless the DSMB is smaller than it appeared.
     
    Wibble likes this.
  3. Wibble

    Wibble Fish don't talk
    UKD Supporter

    Joined:
    Apr 7, 2014
    Messages:
    5,486
    Likes Received:
    1,220
    0.1 litre x 200 bar = 20 litres

    A lot less than both of us calculated the blob's volume.
     
  4. Big Joe

    Big Joe Active Member

    Joined:
    Jan 9, 2010
    Messages:
    918
    Likes Received:
    187
    You measured it flat. If it was round, the radius would have been a lot less and therefore the result would be smaller. HTH.
     
    Wibble, jb2cool and Dave Whitlow like this.
  5. Dave Whitlow

    Dave Whitlow Well-Known Member

    Joined:
    Oct 27, 2010
    Messages:
    1,063
    Likes Received:
    393
    Your measurements do not correctly reflect the internal volume of the SMB, as you've understated the width of the sealed and sewn edge (about 1.5cm each side).

    You are assuming it inflates to a cylindrical form of the same dimensions but a flat SMB measuring 20cm across does not form a cylinder of 9.5cm radius and actually has an oval cross-section (about 13cm x 10cm).

    I recall (can't find a reference) the volume is 15 litres and that matches my experience with partially filled bottles.
     
    jb2cool likes this.
  6. Wibble

    Wibble Fish don't talk
    UKD Supporter

    Joined:
    Apr 7, 2014
    Messages:
    5,486
    Likes Received:
    1,220
    Damn. I'll do my homework again then...

    Right, the internal blowy uppy bit was 19 cm wide when flat. Times 2 is the circumference: 38cm.
    Circumference is 2πR, so radius would be C/2π = 38/6.28 = 6
    So CSA is πR^2 = 3.14 x 6^2 = 113cm2. Therefore the volume of a 1.25m blob is 113 x 125 = 14.1 litres.

    14.1 litres needs 141 100ml crack-bottles-worth of gas to fill it. Call it 160bar to pressurise it.


    Now for the coconut carrying sparrow...
     
  7. hawk

    hawk Doing It Rong
    UKD Supporter

    Joined:
    Mar 29, 2012
    Messages:
    1,411
    Likes Received:
    496
    So what I said then :)

     
  8. Vanny

    Vanny Active Member

    Joined:
    Apr 18, 2016
    Messages:
    550
    Likes Received:
    179
    Does it matter ? The little bottle fills the blowy up thing when it's full. Job jobed.
     
    jb2cool likes this.
  9. Big Joe

    Big Joe Active Member

    Joined:
    Jan 9, 2010
    Messages:
    918
    Likes Received:
    187
    =D> =D>
     
  10. Pothole

    Pothole Member

    Joined:
    Apr 28, 2014
    Messages:
    43
    Likes Received:
    9
    Would this small cylinder be any good to anyone? Bcd already blanked so it's just spare
     
  11. Alex Denny

    Alex Denny Active Member

    Joined:
    Oct 25, 2016
    Messages:
    361
    Likes Received:
    85
    A follow up question to this, all these months later. I have also just picked up a buddy BCD with the little bottle and the plastic valve (not blanked). If I take the bottle off and simply don’t use it, is the old a clamp plastic bit on the BCD a one way / non return valve? I.e. will it work without the bottle if not blanked? Or will it just dump all the air?
     
  12. Dave Whitlow

    Dave Whitlow Well-Known Member

    Joined:
    Oct 27, 2010
    Messages:
    1,063
    Likes Received:
    393
    I believe you need a blanking plate. If you have no use for the bottle then I might have a purpose for it.
     
    Alex Denny likes this.
  13. Vanny

    Vanny Active Member

    Joined:
    Apr 18, 2016
    Messages:
    550
    Likes Received:
    179
    The a camp bit shouldn’t leak but it’s only a rubber band seal inside and isn’t perfect. You can buy a blank which will sit under the ring that holds the a clamp in place. Should be on AP’s website.
     
    Alex Denny likes this.
  14. Tel

    Tel Super Moderator
    Staff Member

    Joined:
    Jun 26, 2014
    Messages:
    1,845
    Likes Received:
    652
    It won't leak as such, but although rare the lack of cylinder exposes the stub which can get caught and
    knocked leading to the fitting working lose. This is unnecessary when the solution is so cheap and takes
    two secs, so better to change it :)

    The older version uses the seal in the fitting and is just a plate, while the later one has it's own o-ring.
    Check the links for the one that fits yours.

    Pre 2007
    https://www.apdiving.com/shop/spare...nance-pre-2007/ap35m-blanking-plate-only.html

    Post 2007
    https://www.apdiving.com/shop/spare...nce-post-2007/apv35m-blanking-plate-only.html
     
    Alex Denny likes this.
  15. Alex Denny

    Alex Denny Active Member

    Joined:
    Oct 25, 2016
    Messages:
    361
    Likes Received:
    85
    Thanks all. I’ve just bought the blanking plate. Dave I’ll ask the wife whether she wants to keep the cylinder and if not it’s yours. It’s an A-clamp one, rather than DIN though, which is a bit annoying!
     
  16. Tewdric

    Tewdric Member

    Joined:
    Jan 1, 2016
    Messages:
    72
    Likes Received:
    17
    Does anyone use the 0.4l suicide bottle for suit inflate? I hardly use any gas in my suit and from that point of view it should be good. if it runs out inflating my suit as my redundant buoyancy system I could disconnect my wing, bring the hose behind my neck and inflate the drysuit from.tbe right. Maybe. or more likely ditch redundant stiff and swim up. Or just swim.up because I know I can. Can you tell I'm thinking aloud here? Or shall I just get a 1l like everyone else..
     
  17. Wibble

    Wibble Fish don't talk
    UKD Supporter

    Joined:
    Apr 7, 2014
    Messages:
    5,486
    Likes Received:
    1,220
    Was doing a day in NDAC once, using a 1 litre suit inflate bottle, where we did a couple or three ascents in the first dive. Forgot to fill it up before the second dive. Descended then ran out of gas. Shrink-wrapping is quite uncomfortable!

    Often now, if using mixed gas, I will tape my suit inflate hose from the LH first stage to my SPG hose. Two reasons: bone idle to remove it and it's useful to inflate a bag/whatever. Also makes it a backup if the suit-inflate bottle failed.

    Note sure that 0.4 litre's enough backup.
     
  18. Tel

    Tel Super Moderator
    Staff Member

    Joined:
    Jun 26, 2014
    Messages:
    1,845
    Likes Received:
    652
    It's possible and i'd be looking to refill after each dive which would be a pain,
    but unless you are swapping out the valve you would need one of these if it's a Din.


    [​IMG]

    The bottle is a male Din and so is the 1st stage :)
    It's just under £20, so about half the price of a new valve.
     
  19. Tewdric

    Tewdric Member

    Joined:
    Jan 1, 2016
    Messages:
    72
    Likes Received:
    17
    Yeah I was thinking about the "backwards" din problem and that's quite a neat solution.
     
  20. nickb

    nickb Active Member

    Joined:
    Oct 13, 2009
    Messages:
    532
    Likes Received:
    237
    Back in my early OC twinset days, I used one with a DIN valve I bought from AP, I think it's M14. It was great for one square profile dive to 45-50m or a couple to 20m(ish)

    I put a couple of jubilee bands on it with some webbing and wore it on my harness waistband.

    It's now relegated to a helium bottle to use as bump gas for calibrating my analyser.
     

Share This Page

Users found this page by searching for:

  1. filling a buddy bcd bottle you tube

  • About Us

    Our UKDivers community has been around for many years and prides itself on offering unbiased, helpful discussion among people of all disciplines and abilities. We are working every day to make sure our community is one of the best and friendliest around.
  • Support us!

    The management works very hard to make sure the community continues to run reliably. Care to support us? All donations go to the running costs of the forum: hosting charges, software maintenance, etc. We'd really appreciate it!

    Choose option:  

    UKD Username: