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Buoyancy Propulsion and Trim

Discussion in 'Basic Scuba' started by Bigd2722, Jul 18, 2015.

  1. Bigd2722

    Bigd2722 Solo Diver

    # of Dives: 500 - 999
    Location: Winter Park, fl
    Recently spent a few days in the Keys taking a couple of classes from "Netdoc". The first class was Pete's insane (his words on the web site) Bouyancy Propulsion and Trim. Now, I have 19 years experience and over 600 dives so I don't qualify as a beginner, but I always felt that buoyancy was not my strong suit. We did this class over 3 days, although I'm sure you could make more or less of it depending on your schedule. Our first day was in the pool and consisted of working on proper weight, practicing air share and propulsion using mostly frog kick style. Pete has a couple of exercises involving weights that help you realize how much wiggle room you have in order to be not over or under weighted. The second day was at Cannon Beach in Pennekamp State Park. There's an interesting history to the area as it was used as a practice site for D Day. We also saw a free swimming frog fish. A first for me. The third day was a bonus in that we got to dive the Bibb. I had never had the opportunity before and really enjoyed it. It did not strike me as an especially advanced dive although it has that reputation. Perhaps we just caught it on a good day. There were another couple on the boat who completed their 32nd dive and still manage to survive. In short, the time was well worthwhile to me for the tips and tricks I picked up, the diving (always a good thing), and the multitude of stories Pete has to share. I would recommend this class to anyone wanting to improve their diving skill set.

    Thanx Pete.
    boulderjohn, Altamira, D_B and 3 others like this.
  2. RJP

    RJP Scuba Media & Publications

    # of Dives: 1,000 - 2,499
    Location: New Jersey
    The "Holy Trinity" of scuba diving.
    D_B, mselenaous and northernone like this.
  3. glock34girl

    glock34girl Registered

    # of Dives: 25 - 49
    Hi There:

    Please don't flame me for what I am about to ask. I want to make sure I have these straight in my head:

    Buoyancy - how you float in the water either negatively(sinking), Positively (floating) or neither (neutral).

    Propulsion: How you move through the water... flutter kick, scooter, frog etc.

    Trim:... I am not exactly sure.... is this sort of what causes me to change angles in the water?? Feet up, head down or side to side???? Sorry, I am a newbie.

    D_B likes this.
  4. KevinNM

    KevinNM DIR Practitioner

    Pretty much. Trim is the angle of the diver in the water. Under usual circumstances that should be roughly horizontal, with the shoulders to knees all in a roughly straight line.
    D_B and glock34girl like this.
  5. The Chairman

    The Chairman Chairman of the Board Staff Member

    # of Dives: I just don't log dives
    Location: Cave Country!
    First, Thanks to BigD for the more than kind words. It's a fun class because you came to learn. Some people find they worked harder in this class which never comes with a c-card. :D

    As for the question about trim: it's the missing piece for most to the buoyancy puzzle. It your attitude (angle of propulsion) is not horizontal, then your kicking will force you up or down in the water column while also (hopefully) pushing you forward. If you set your buoyancy to counter these forces, then when you stop to look at something, you'll be immediately too heavy or too light. However, if your propulsion is horizontal, then your buoyancy remains stable, even when you stop. Instead of taking a hundred dives to master buoyancy, a student can master this skill in just a few dives if they get their trim horizontal.

    Every student is different. I can usually tell within the first lap or two in the pool what a student really needs to work on and every class is adjusted to their needs. BigD was pretty close with his trim and converting him to the frog kick, which is the easiest kick to get horizontal propulsion from, gave him the stability he needed. It wasn't much of a tweak, but it made buoyancy control a lot easier for him. He also learned to establish his buoyancy before attempting any task. The tweaks are usually small, but they are so important to keep you from floating to the surface or wreaking havoc with silt by sinking.

    As an aside, this is my absolute most favorite class to teach but no, it doesn't come with a c-card as NASE feels that this is a remedial skill that all OW water students should have already learned.
    RJP, D_B and glock34girl like this.
  6. glock34girl

    glock34girl Registered

    # of Dives: 25 - 49
    I have about 40 dives and each one gets more and more frustrating for me. I seem to be able to stay somewhat where I want to be if I am moving but stop to look at something and I am usually plummeting to suck on an urchin. I have noticed that I am more probably at a 45 degree angel than horizontal. I have been terribly frustrated because one dive seems okay and then the next dive I am surfacing faster than Id like. Sometimes when I am at depth I feel like I have too much weight but then when I am a bit shallower around 15-18 feet i have to be very careful not to take a full breath or its a rocket ride to the top. I also think I just discovered why my knees are killing me after a live aboard. Besides kneeling on the swim deck I think Iam kicking with my knees rather than my hips. Hmm. A lot to think about.

    ---------- Post added July 19th, 2015 at 09:21 PM ----------

    Wish NetDoc was in Cali.
    D_B likes this.
  7. KevinNM

    KevinNM DIR Practitioner

    People typically finish an OW course with too much weight for a variety of reasons (breathing, finning, etc). So if you haven't adjusted this you probably have too much weight. Having trouble with a safety stop is often because someone needs to keep air in their BC because they are too heavy, and even a minor rise in depth when you are shallow results in all the air in your BC expanding, and up you go.

    Once you get weight right trim is largely figuring out how to distribute the weight so it tends to keep you horizontal vs vertical.

    Both weighting and trim are a lot faster to fix with a skilled instructor or mentor helping.

    Oh, and kicking with your knees rather then your hips is another flutter kick technique. It works well once you get weighting and trim right.
    D_B likes this.
  8. D_B

    D_B Kimber/TekDiveGirl storyteller and memory keeper ScubaBoard Sponsor

    # of Dives: 50 - 99
    Location: San Diego, Ca.
    great post, good questions

    glock34girl ... it sometimes helps if you think back to a teeter totter / see saw ... once you have the correct amount of weight, removing wight from one end, and putting it on the other will tilt you in the water ... that's the basic premise ... usually only a small change is needed to get you in trim (I hope I didn't just make worse your understanding with my try to help you)
  9. mselenaous

    mselenaous Island girl ScubaBoard Supporter

    # of Dives: I just don't log dives
    Location: Key Largo, FL... Dive Capital of the World
    Too funny at the "insane" comment. I think the word is "snobbish". The nickname came from thez_yo, a UTD diver, who said her buddy, aeweems had "snobbish amounts of trim" when she finished Netdoc ' s class.

    Glock34girl, come on down to the Keys. :)

    There are some good instructors on the west coast that could work with you and provide some mentoring. These are the ones who come to mind:
    Robert Arak of ScubaTude
    Peter Guy & TS&M (Lynne)
    NWGratefulDiver (Bob)

    Sent from my SM-G900V using Tapatalk
    D_B likes this.
  10. TheHobster

    TheHobster Master Instructor

    # of Dives: I just don't log dives
    Location: Indianapolis
    Where bin California. I h underwave some friends in SoCal that might be able to help. One is an instructor and a cave diver. He has his s*** together underwater.

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