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Sidemount or Backmount?

Discussion in 'Cave Diving' started by Tickler, Dec 12, 2013.

  1. DevonDiver

    DevonDiver N/A

    # of Dives: 5,000 - ∞
    Location: Subic Bay, Philippines
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    I teach technical wreck (not cave, yet), but the issue of restrictions and confined spaces exists in both. On those courses, I have students in both sidemount and backmount configurations. What I see, as an instructor, is that the sidemount configured student divers enjoy considerably less stress when moving through confined areas. Not just 'small restrictions', but more generally in the overhead environment.

    Of course, unlike Ragnar, I don't have the luxury of only diving 'upright' wrecks - so passages, doors, hatches etc may present themselves at all angles. Some wrecks, especially Japanese, have much smaller doors/passages. The sidemount diver can maneuver through those areas, altering their trim as necessary. They can jack-knife, twist and flex to fit around any corner, pass obstructions or fit through any shape of restriction - more often than not without even needed to make use of their capacity to partially disengage and swing forwards their cylinders.

    The backmount diver is very limited in that capability and I see, first-hand, much more struggling. I also see, or rather hear, plenty of valves clanging loudly against structure...

    What I describe above isn't passage through extreme restrictions - it's generally moving around passageway/decks inside the wrecks. There are vast areas inside the wrecks I dive that are wide open to sidemount divers, but remain impassable, or highly advanced, for backmount divers.

    With regards to diver safety - well, a sidemount diver has the option to exit the wreck in an emergency though smaller areas. In the same circumstances, a backmount diver could be trapped... and could die. I like that sidemount gives me more options to escape a wreck, should that ever be necessary.
     
    nimoh likes this.
  2. Razorista

    Razorista Manta Ray

    # of Dives: 1,000 - 2,499
    Location: Germany
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    I do not dive wrecks or restrictions much, as the lakes I dive in mostly contain neither. Similar to other sidemount novices I have a tendency to search for small openings to squeeze through, however.

    What I like most about having no restricting material on my back is the difference in the way you experience the environment that way.
    Bending your back to look up and inspect ceilings in passages feels natural and when things get tight and it is much less guesswork and risk to touch areas above you with your body (and not the tank).

    There is also the aspect of being more stable in non-horizontal orientation.
    If passages bent up or down the sidemount diver will just shift persective and will drift over the angled floor without seeming to notice.
    Since this needs only a shift I posture, there is no need to move fins to shift position and the water moved by the fins for propulsion is easier to control.

    Oh, and I forgot about equipment: butt-mounted equipment and pockets are easy to reach in any situation and make many areas seem less restricted.

    All in all most areas that appear 'restricted' to many backmounters feel like cathedral halls to me :D (ok a bit much..., 'normal', at least)
    I have actually lost perspective there on the last 500 dives - the sound of a backmounter ramming himself into an opening I just went though without noticing is something I can identify without looking up by now :wink:
     
  3. Ragnar

    Ragnar Solo Diver

    # of Dives: 1,000 - 2,499
    Location: Guam Via CT
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    Nice illustration except that the box representing the backmounted doubles is way too big while all the others are amazingly the correct size!:wink: Make the backmounted box the correct size and what you have is half the diameter of the tank larger, which I'll buy as about correct....

    Struck a nerve with this one I see, and will concede there are some flaws in a few of my arguments, but that still leaves a lot of valid arguments for my point, especially for open water. The mere fact that you won't even award that one to me is proof that no matter what evidence is presented you don't have an open mind about it.

    ---------- Post added December 20th, 2013 at 10:41 AM ----------

    Actually, two of the three bigger wrecks I dive regularly are fully on their sides. You have experience back-mounting and side-mounting where I only back-mount so can't compare on as many points as you, however for many of the reasons I've given BM is a better setup for a wider range of diving than SM and this craze to SM as a better system for MOST diving including open water is just pure silly. It's a better system for getting into really tight places, that IT!!
     
    Last edited: Dec 20, 2013
    Pullmyfinger likes this.
  4. Razorista

    Razorista Manta Ray

    # of Dives: 1,000 - 2,499
    Location: Germany
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    This assumption is completely wrong now.
     
  5. DevonDiver

    DevonDiver N/A

    # of Dives: 5,000 - ∞
    Location: Subic Bay, Philippines
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    The point was, you were talking about shape. Which shape is a door?

    Unless you live in Hobbiton... :wink:

    Proof doesn't exist on the internet - but if you're ever in the Subic area, I'll happily take you on a run through some technical wreck penetrations so you can see the realities...

    Ummm.... think about what you're saying...
     
    Doppler likes this.
  6. nimoh

    nimoh Public Safety Diver

    # of Dives: 500 - 999
    Location: Rochester, MN
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    I agree there are advantages with sidemount, and could definitely see myself doing sidemount at some point, although backmount seems to be serving me well now.

    My earlier comment was more about how well your illustration shows the advantages of sidemount. I do agree with Ragnar that the backmount square could be a bit smaller, but I don't think this would significantly change the message of the illustration.
     
  7. DevonDiver

    DevonDiver N/A

    # of Dives: 5,000 - ∞
    Location: Subic Bay, Philippines
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    What range of diving?

    Serious question - lets all list the pros and cons of both configurations, from a range of diving.
     
    FM1520 likes this.
  8. SanDiegoSidemount

    SanDiegoSidemount DIR Practitioner

    # of Dives: 200 - 499
    Location: San Diego, CA
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    My main reason for diving sidemount is to spare my back. I've had spine surgery, and can't carry doubles on my back without serious risk of further injury.

    Slinging one tank off each hip in sidemount configuration is easy. Bonus: low CG makes beach entries more stable when the surf's up.

    I personally couldn't dive doubles any other way. Singles are more of a tossup. I do like the simplicity of my BP/W rig, it's a bit cleaner than my sidemount setup with all its bungees and stage rigging.
     
    Doppler likes this.
  9. Doppler

    Doppler Dive Equipment Manufacturer

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    Hummm. Didn't I read somewhere you offering a critic on SM? Nah, must have been someone else.

    I've dived both setups... a lot... and whereas these days I would dive backmount in a cave if I had to, I would not think about going into a wreck in backmounted doubles... not a real wreck.

    Allow me to explain. I teach cave and advanced wreck and had the good fortune to help develop the original Advanced Wreck program for TDI. Only in that program and SDI Solo Diver is the instructor allowed (and encouraged) to tie the student up... in other words, simulate an entanglement... I mostly do it when the student has on a blacked out mask once they manage it "normally." For backmounted students, it's a struggle either way. For students configured sidemount (correct SM not this front-mount nonsense), the exercise when they can see it over pretty much over in three or four seconds... even when they are unable to see it's done in half to a quarter the time.

    Just saying

    It's not my intention to put down or promote one kit configuration over another... all the good ones work and they all have a place in the toolkit... Not specifically directed at you... but here on the internet, it seems there are a lot of people saying that SM is wrong for reason A or application B when they have zero experience with it.

    Seem odd to anyone else or just me and Andy?
     
    sskasser and Dive-aholic like this.
  10. victorzamora

    victorzamora Solo Diver

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    It seems odd to me as well. I get, and understand, that sidemount was not designed for open water dives. I understand sidemount was designed for ultra-tight restrictions only. However, I can't agree that it is any less good than BM in the Open Water. If you're carrying 8 tanks, yeah...I get it....strap some to your back, there's a LOT of space there. That's a cogent argument for the "Real-estate" argument. However, as far as I see it, they trade pros and cons.

    Sidemount
    Pros:
    More stable
    Can use any two identical cylinders
    Can see valves
    Fully redundant
    Flatter profile
    Less rigid
    Featherable valves
    Easily removable

    Cons:
    Less standardized
    Lots of fiddling, unless instructor is good
    Wider profile
    No manifold
    OOA might be from temporarily "dormant" reg

    Did I miss something?
     
    Razorista and Doppler like this.

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