• 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

Balanced Rig - GUE - NEWB

Discussion in 'Advanced Scuba Discussions' started by Heat Miser, Sep 1, 2019.

  1. Heat Miser

    Heat Miser Angel Fish

    # of Dives: 100 - 199
    Location: Perth
    18
    22
    3
    Hi All,

    I recently (May 2019) completed a Fundies course in Sydney, I didn't smash it, however I did come back to Perth and firstly, buy a Back Plate & Wing (BP/Wing) plus Jet Fins and secondly, commit to some bottom of the pool time, working on trim and buoyancy when task loaded. I hope to redo / upgrade to a rec pass soon, subject to travel/work commitments.

    I went out on the (great ****) Lionfish dive charter boat last weekend and the Divemaster (a good / genuine bloke) was a bit concerned with the way I've rigged my weights. Generally I'm a little/big guy 101 kg / 222 lbs, short, but aerobically pretty fit. So wearing a 5/7mm wetsuit, with steel Halcyon Back-Plate, plus I had 6 kg or 13 lbs of weights of which only 3.5 kg or 8 lbs was dumpable.

    Anyway, with a new focus on buoyancy (and holding a safety stop / 4 x 1 min 3 meter intervals) I guess perhaps I hadn't focused on swimming the excess weight up, if I had a wing failure. I doubt whether it would be a problem. I regularly swim 10-20 ks 2-3 times a year. Have big lung capacity and I spend most of my time now trying to inhale/exhale slowly, rather than the gulp air down when I'm in an ocean race.

    But have I neglected the 7kg / 16 lbs I'd have to swim up from 25-30 meters with a wing failure, after I have dumped 3.5kg / 8 lbs of weights?

    Should I test it and how is the safest ... hand a buddy the dumpables at 25 meters?

    Regards
    DIR NEWB
     
  2. Jim Lapenta

    Jim Lapenta Dive Shop

    # of Dives: 500 - 999
    Location: Canonsburg, Pa
    16,854
    8,523
    113
    How did you determine what was needed to be dumpable? Also, what is your back up buoyancy device? Lift bag, large DSMB? If your wing fails and you need to dump lead to start to swim up, don't forget that your suit is going to provide additional lift as you ascend. The neoprene will start to lose compression.
    Having teammates near you to assist in a little exercise like handing off a kilo of lead to and then deflating your wing and trying to swim up may be a good way to check.
    Being a tech instructor I always have a backup for wing failure. Drysuit, lift bag, DSMB, etc.
    The other thing that DM's and many instructors seem to forget when they see weights that can't be ditched is Boyle's law. As depth decreases, pressure does as well and volume increases so that buoyancy increases. Your suit will start to provide the additional buoyancy you need.
     
    peocro, leadduck and Heat Miser like this.
  3. Heat Miser

    Heat Miser Angel Fish

    # of Dives: 100 - 199
    Location: Perth
    18
    22
    3
    I guess that my question "How do I determine what needs to be dumpable?"

    Also I have a large SMB - Its prob 9kg/20lbs, are you saying if theres a problem inflate the SMB and stick it under your arms? Makes sense... I never thought about it. Certainly I didn't cover it in Rescue Padi / nor Fundies.
     
  4. johndiver999

    johndiver999 Manta Ray

    # of Dives: 500 - 999
    Location: Gainesville FL
    762
    639
    93
    You concerns are VERY valid and if you take the time, this tool and the thread should provide you the EXACT answer that you are searching.

    Optimal Buoyancy Computer
     
    Heat Miser likes this.
  5. g1138

    g1138 Marine Scientist

    # of Dives: 500 - 999
    Location: Charleston, SC
    3,051
    779
    113
    If you want a quick test, try treading water in just swim trunks & fins. Have your whole rig, tanks, and weights on and tread for 10 minutes with no air in the BC.

    That will be a worst case scenario with 0 buoyancy, say if your weight suit was fully compressed at depth and your wing failed.

    If you can't do it dump the ditch weights and try again. If you still can't do it or easily fatigue then you've identified a risk and can rearrange more dumpable weights to correct for it.
     
    Heat Miser likes this.
  6. Marie13

    Marie13 Great Lakes Mermaid ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Great Lakes
    5,378
    3,715
    113
    Did you do the class single tank or doubles? If it was single tank, why aren’t you duplicating weighting you had in class?
     
    Heat Miser likes this.
  7. Heat Miser

    Heat Miser Angel Fish

    # of Dives: 100 - 199
    Location: Perth
    18
    22
    3
    Well I have different gear on these day then from the course, the class was in Sydney which is 1,500 miles from Perth. Think San Diego versus Florida.

    I have a single tank with Steel Back-Plate on my new 30lb wing now, In Sydney it was in a single tank with a back plate that had some sort of integrated weights. Also in Sydney the wing was larger at least 40lb (but felt like 60lb), I'm not certain how much larger, but it certainly taco-ed around the tank too much, though as a NEWB, I didn't appreciate that this was a problem, until I got back to Perth and tried some better fitting gear. My new Jet-fins weigh more than the old/new Tusa's.

    Finally I think the way I dived pre-course was negatively buoyant with alot of hand finning, post course my hand aren't flailing around as much and I'm much more neutral although far from text book yet. Pre course my RMV/SCR was 24 l/min Post course RMV/SCR 18/ l/min.

    All these things have an effect on total weight needed, but in the course there wasn't a great deal of discussion about how much should be dumpable. Or if there was I missed it, because the I was stressing about back-kicks or Minimum Gas calc, or something else when dumpable weight was touched on in the course.

    Anyway I like all of the practical suggestions to date....I love spreadsheets too ... so thanks to all for ideas.
     
  8. johndiver999

    johndiver999 Manta Ray

    # of Dives: 500 - 999
    Location: Gainesville FL
    762
    639
    93
    The spreadsheet should be helpful, but if you are inclined to experiment, simulating a failed BC is pretty easy. Swim to the bottom, with full tank, burp every last bit of air from the BC and watch your computer (to judge the ascent rate) and start kicking those big, heavy jet fins. Are you going up? Is the work load sustainable? Is it something you think you can do in a real emergency? It will get easier the closer you get to the surface, but with a thick suit, you may be too weak to make the swim. This is about you, not some theoretical diver on the internet.

    Once you determine if you can (or can't) make it to the surface with a failed BC (and not dropping lead) then you can decide IF you should be carrying some ditchable lead. The spreadsheet can be hugely beneficial in helping you make a safer weighting configuration.
     
    Heat Miser likes this.
  9. rvojr

    rvojr ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 25 - 49
    Location: Williamstown, NJ
    93
    60
    18
    I referred back to a spreadsheet they showed us in my fundies class. It showed weight and needed ditchable weight. I have been able to remove 14 lbs of weight over the last couple months between the class and further comfort in the water. HP100, negatively buoyant fins and SST backplate is enough for my 8/7 semi dry but in fresh water. Everything but the fins were the same prior to the class. You may want to go to an aluminum backplate and AL80s you should be fine if you are not overweighted with additional ditchable or trim weight. I still have not gotten to around to weighing each piece of equipment in the water so I can fill in the spreadsheet accurately. As mentioned to me by many instructors, when in doubt at the end of a dive do a weight check with an empty wing.
     
    Heat Miser likes this.
  10. decompression

    decompression Instructor...seriously...

    # of Dives: 5,000 - ∞
    Location: Victoria, BC, Canada
    3,960
    1,464
    113
    Back to balanced rig school......so the heaviest you’ll be is at the beginning of the dive, assuming you’ve gone through proper weighting......the weight of gas what you are “negative” so you compensate by adding air to the wing. So, the weight of the air can be ditched if there’s a wing failure. Usually 4-5 lbs. this should also be “swimable” if not ditched.

    If you are at 30m, you must have a redundant source of buoyancy.
     
    Heat Miser likes this.

Share This Page