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Side Mount Aluminum 80s, setup with no weights?

Discussion in 'Sidemount Diving' started by SentinelAce, Oct 17, 2018.

  1. northernone

    northernone Contributor Rest in Peace ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Currently: Cozumel, from Canada
    3,792
    3,408
    Here's what I've figured out so far between SM diving in Canada and Mexico.

    Two systems of SM.
    1. Designed for tanks which float when near empty.
    2. Designed for tanks which stay negative and behave as ballast.

    The easy way to use system #2 with al80s is make them negative by adding weight. (Ideally streamlined and well attached.) Otherwise you need to modify the BCD harness to look like system #1.

    When I switch between lp131s and al80s the same day with a #2 I add lead to my tanks. When I dive al80s for months I use a #1 style setup.

    Where #1 style harness configuration is rare people still add lead.

    Do what works.
    Cameron (A pretty ugly, starting to be experienced, SM diver)
     
  2. Rollin Bonz

    Rollin Bonz *insert catchy phrase here* ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: Georgia, the state, not the country ;-)
    520
    430
    I dive sidemount using AL80s in both a Hollis SMS75 and SMS100. I don't use weights on the tanks. I use fixed D rings on the waist straps instead of the rails for my tanks. I tried using the rails/doorknobs with AL80s at the start of the dive (then move them to the D rings as they become more buoyant), but found it impossible to achieve proper trim, so I start with the tanks on the D rings. Most will say the rails are for steel tanks and I agree, at least for me. I believe there are a few threads here arguing for and against weights on the tanks. Although you will find a vast majority against the practice, and doesn't appear to be the best solution, some have their reasons to do it, and it seems to work for them...
     
    Johanan likes this.
  3. Rollin Bonz

    Rollin Bonz *insert catchy phrase here* ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: Georgia, the state, not the country ;-)
    520
    430
    I think that is a great way to summarize!
     
  4. decompression

    decompression Instructor...seriously...

    # of Dives: 5,000 - ∞
    Location: Victoria, BC, Canada
    4,193
    1,726
    A very large part of SM is tank selection. The rig and the tanks form one unit. Ideally tanks should be neutral to slightly negative at the beginning of the dive. You can’t always get the tanks you want so you dive what you get. If that’s the case choose a rig that accounts for that. As mentioned, placing weights on tanks can be looked at as lazy, lack of skill or as a bandaid. Luckily there are rigs that can dive both very well and there are those that look like a dog humping a football.
     
    Rollin Bonz, rjack321 and JBFG like this.
  5. rjack321

    rjack321 Captain

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, Washington State
    10,966
    5,632
    I'm lazy and I've put weights on al80s. I need the lead anyway, and its more comfortable there than having a bigger weight belt (I max out the weight integration system on the harness/bc). 2lbs on the cam band is not the drama filled soap opera you make it out to be. Additionally, if there's trimix in an al80 it will never want to lay flat and in trim even when its full.
     
  6. rddvet

    rddvet DIR Practitioner

    # of Dives: 50 - 99
    Location: Florida
    1,504
    1,416
    Go down to mexico and you will get snickers and jeers. In florida, you will too. Even with trimix it's unneccssary. If you're doing it just to put weight somewhere that's a little more understable. To do it because you can't control the butts of your tanks is sad.
     
  7. scuba127

    scuba127 Contributor

    # of Dives: 200 - 499
    Location: Urbandale Iowa
    385
    61
    I've used 2 stationary drings, the triangle method using double enders and, last trip, sliding d rings with aluminium 80's. I'm finding I prefer the sliding d rings....I started on a stationary d ring and then switched to the slider during the dive....thought about it after the trip and wondered if anyone uses just the sliding d ring....no stationary d ring at all....respect to the OP.....hopefully I haven't hijacked the thread....
     
  8. rjack321

    rjack321 Captain

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, Washington State
    10,966
    5,632
    I wouldn't use Al80s in FL when lp50s or 85s are readily available and far superior cylinders.

    SMing an 80 of 21/35 on one side as BO in the great lakes, yes I want 2lbs (or even 3lbs) on the cam band. I don't want to front clip that to keep the butt end down because then there's no offset on the buttplate for the EAN50 bottle on the other side (which is significantly heavier).

    Carry on with your broad brush assumptions about competency, skills, and what's "necessary" based on where a chunk of lead is placed.
     
  9. northernone

    northernone Contributor Rest in Peace ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Currently: Cozumel, from Canada
    3,792
    3,408
    I've found the vast majority of cave divers around tulum/playa/cozumel are kind and helpful and have grown up and matured past those kinds of disrespectful attitudes.

    Rudeness and ridicule for gear choices is pretty classless.

    Thankfully I rarely meet that kind of diver.

    (Conversations about avoiding damage to delicate systems is another story.)

    It's easy to make fun of a configuration we view as not the perfect one.

    With those disclaimer, I do suggest a #1 style configuration for aluminium/CF tanks. IDEALLY with someone experienced and competent to help get you sorted.

    That wasn't how I learned and it was ugly for a long time. (Sometimes still is in OW.)

    Cameron
     
  10. tanstaafl99

    tanstaafl99 Registered

    21
    5
    I strictly use sliding d-rings. No stationary d-rings on my waist at all.
     

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