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dry suit bouyancy

Discussion in 'Exposure Suits' started by chuckrt, Sep 5, 2002.

  1. chuckrt

    chuckrt Barracuda

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    I have been diving with my drysuit now for a couple of months and I am not comfortable using it as my bouyancy control. I no there has been many opinions expressed and the manuals state to use your suit only unless on the surface. I also feel I have to make up my mind which is better for me, BC or Suit. Here are the main questions. How much air is required to relieve suit squeeze, should some be alright? And when in really cold water and using argon isn't more in your suit going to keep you warmer? As you go deeper do you add more air for the squeeze , and less in your BC?

    Chuckrt
     
  2. Bob3

    Bob3 Dive Shop

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    You're better off using your BC for the use it was intended; offsetting the effects of compression & adjusting for the buoyancy difference of the air consumed. Add air to your suit for the purpose of squeeze relief. Adjust your suit first, as this will affect your buoyancy.
    Go easy on the suit inflator though, it's real common to over compensate when you're first learning how to use the suit.
    If you're using a shell suit, adding a spritz of air to the suit as you descend will also offset the effects of "undie compression" & you won't need to use the BC much 'till you use a bunch of air from your tank.
    You'll ALWAYS feel some squeeze from your dry suit, it's just the nature of the beast. The squeeze is much less noticeable if you remain in a horizontal position as much as possible. When you're vertical, there's a considerably larger difference in water pressure at your feet.
    After a while you won't even pay much attention to that little bit of squeeze though, it's just something you get used to.
    Think of it as your drysuit giving you a nice warm fuzzy hug, it's very comforting. Try to resist the impulse to take your suit to bed with you though, folks will start to thing you're even wierder than you are.
    Using argon doesn't make a whole lot of difference, it's mostly all in your head. If you THINK it keeps you warmer, you'll probably feel warmer, so in that sense it may justified.
    The only time you need to use a seperate suit inflate bottle [with argon or air] is when you're diving a helium mix, Helium carries off the body heat like a bandit.

    What is your suit material?
     
  3. chuckrt

    chuckrt Barracuda

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    Hi Bob3,

    Thank You for your reply. My suit is a shell style suit. I also wear a Jacket BC and I am comfortable with this style. I changed to a Dui weight harness from Integrated and weight belt and found that it puts a different balance in my position as well. I have been able to get fair control using the suit only but not nearly as well as when I used my BC and wetsuit.

    chuckrt
     
  4. IndyScott

    IndyScott Instructor, Scuba

    # of Dives: 500 - 999
    Location: Indianapolis,Indiana
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    The more you dive in it the quicker you will become better weighted. ;)
     
  5. Rickoz

    Rickoz Nassau Grouper

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    I too am new to drysuit diving love it :)

    I've had no problems with my bouyancy (shell type)
    But have only used the suit to reduce squeeze not as a BCD & was going to play around next time I dive, but youv'e saved me from a maybe notso good dive anyway thank's bob for you info without all the bullsh!t thanks mate :thumb:
     
  6. Lost Yooper

    Lost Yooper Loggerhead Turtle

    # of Dives: I'm a Fish!
    Location: Panama City Beach, FL
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    It's the underwear that really keeps you warm, not the air so much. You're much better off using the BC for what it was intended for (buoyancy control) and the suit for what it was intended for (keeping you dry). The reason most people use (and teach)the suit for buoyancy control is that it's the quick and easy route, not necessarily the best route.

    It takes a lot practice, but you'll get it.

    Mike
     
  7. SubMariner

    SubMariner C'est Moi ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: A Canuck Conch
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    Frankly, this is the same type of question as what kind of gear to buy: it's very much based on personal opinion.

    Some agencies/manuals tell you to use the suit only for buoyancy control u/w and the BC only at the surface; others tell you to use the BC for bouyancy control and only put a small amount of air into your suit to offset squeeze.

    Obviously, there are pros & cons to EITHER method. It's up to YOU to decide which one works best for YOU.

    As for how much air is required to relieve suit squeeze: again, very subjective. It also depends on the type of suit you are wearing & how much it squeeze the suit material allows. Full 1/4" neoprene suits very rarely experience suit squeeze, while shells almost always start out with some until you put air into them.

    One way to offset "pinching" or "squeeze" of the suit is to always wear long sleeved/long legged garments under the suit. Contrary to common belief, you CAN get long sleeved Tshirts and/or leggings in a variety of thicknesses or materials that will keep you warm with very little bulk. (E.g.: long sleeved poly that shirts skiers or hikers wear.)

    ~SubMariner~
     
  8. budgy

    budgy Instructor, Scuba

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    Hi chuck, I dive with a single tank, its easier and less complicated to use just one form of buoyancy and as I have to put air in the suit I just use the suit. Lots of people are oveweighted which means they sink like a stone and then have a big bubble of air sitting on their shoulders to get neutral. I think this is what makes it difficult, the extra large volume of air makes buoyancy changes due to ats more acute and you have a lesser ability to effect change with your lungs. Trim is another big factor, Uncle Pug tipped me to fastening my bcd higher on my cylinder to achieve a better horizontal balance because my feet were a bit light, I am using heavier fins now, gone back to jets. Suggest you use a cylinder with 40/50 bar and on the surface add on just enough ballast to sink on exhale yet float about mask level on inhale. I took a diver out last weekend and helped him take off 4kgs. He felt a bit bouncy breathing and had to learn to deflate and exhale to get down but he felt whole lot better, his air consumption rate also improved. Get a 30ft shot line and practice ascents and stopping at your safety stop level. Add air in small squirts and pause, the increased buoyancy takes a moment to take effect, dump air in small amounts, do it slow get it smooth.
    With a little practice I am sure you will get it right. Happy diving
     
  9. Soggy

    Soggy Dive Shop

    # of Dives: 200 - 499
    Location: Natick, MA
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    Almost immediately after my dry suit class, I began realizing that using the BC for bouyancy and the suit for squeeze is a lot more comfortable. The biggest problem in using the suit for bouyancy for me is the extra volume of air in my legs....kicking becomes much more tiring. I try to maintain a very slightly heads-up position to compensate for this, but it still is a problem.

    Always adjust the drysuit for comfort FIRST, then go and adjust your BC. That way you aren't playing the balancing game.

    In certain situations I would use my suit for primary bouyancy however. Take my dive on monday night...I was carrying the flag in my left hand, my flashlight in my right. Now, my left hand had to deal with venting my BC, grabbing my computer, and adjusting the flag. My right hand dealt with inflating my suit, using the light, and doing any of the other assorted tasks that might be required. I was definately task loaded, as I am new to night diving (but it is darn cool!). In retrospect, I think I would have felt much more comfy if I had just used my suit for bouyancy, as a simple raise of the arm would have been enough to vent on the way up.

    Now, I started drysuit diving the day I started my certification courses, so in the beginning it was benificial to use oonly the suit for bouyancy as it was much less complicated. Then I moved on to adjusting both.
     
  10. chuckrt

    chuckrt Barracuda

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    I was finally able to get a couple of dives in where the current didn't drive us out of the water. I was in my comfortable dive site in A-Bay on the Islander. When down on the wreck in 25'I adjusted the suit for squeeze and then used the BC for bouyancy. I only had to adjust a couple of times with the suit and found much better attitude in finning and my feet stayed level most of the time. Deepest depth was 62' averaged 40-45' most of the time. When I'm more comfortabe I will try and start reducing the weight a little at a time.

    chuck
     

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