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"limp" SMB

Discussion in 'Basic Scuba Discussions' started by fjpatrum, May 9, 2012.

  1. fjpatrum

    fjpatrum Loggerhead Turtle

    # of Dives: 25 - 49
    Location: DC area
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    I finally got some practice deploying my SMB from safety stops on my most recent trip to FL. We did 6 boat dives so I attempted, 6 times, to deploy this thing. I found that I need a lot of practice, and perhaps some tutelage because not once did it go as planned. The 5th dimension videos on u-tube make this look very easy, and I didn't have any tangling, but it isn't as simple as it looks, that's for sure.

    Primarily my issue is that from safety stop depth, I can't seem to get enough air in the 6 foot marker to get it to stand up on the surface unless I allow it to carry me to the surface also. At best I was getting the marker half full so it just lay on the surface when we arrived.

    My brother bought one on this trip and his has some weights, maybe a 1/4 or 1/2 pound sewn into the duck bill flap, which I thought was an excellent idea. I'll probably add a heavy fishing weight or something to my marker, but do you experienced folks have any other suggestions?
     
  2. Rainer

    Rainer DIR Practitioner

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    Most of the 6' markers are around 50# of lift. Even shooting it at 33' (2 ATA), you'd need to put in 25#. You just aren't going to manage to get 35+# of gas into such a bag from 15'. These larger markers are best shot significantly deeper (e.g. 70'). If you want to shoot something shallower, you're better off with a smaller 3-3.5' SMB (the 3.3' Halcyon one is quite nice, and at 6# of lift, extremely easy to shoot shallow).

    A 6' marker lying flat on the water is a lot less visible than a 3' marker standing erect. You can always carry a larger marker to inflate once at the surface. Or again, just shoot your bigger bag a lot deeper.
     
  3. g1138

    g1138 Marine Scientist

    # of Dives: 500 - 999
    Location: Charleston, SC
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    I carry a 6ft/40lb SMB from Piranha (made by Blue wave....I think). Usually I inflate about a quarter of the way at 20ft and shoot it up. It ends up being a fat "halcyon 1m" sized marker on the surface. I then have 3 ft of SMB below the surface, meaning I can clip off my spool and go hand over hand on my SMB before I break the surface (keeps the SMB upright the whole time).
    Weights aren't necessary to keep the SMB up, especially when you have a portion of the SMB deflated and submerged.

    I find that I don't have enough weight to keep my SMB fully inflated and upright unless the water is absolutely calm. Even then my trim has to be near vertical. I'd rather keep my swimming trim and have a short but upright SMB. In which case a 3ft by 7in marker is fine enough for me and the boat crew (probably around 15-20lbs of lift).

    During a moderate current, I fully inflated my SMB and ended up getting slowly dragged up while swimming. I had to be at a near 70degree down trim to swim forward. The current would drag my SMB back behind me, "shortening" my line.
    I haven't fully inflated my SMB since that dive and haven't had the problem again yet.

    After you deploy your SMB you only need 1-2 wraps around your finger spool to get it upright (assuming it's not fully inflated). You should be able to keep horizontal trim while keeping tension on the line.
    When reeling up, I grab the line in my off hand, create some slack between it and the spool, and then rotated the wrist on my spool hand to wind up. I usually keep the double ender on the line at this point so I can clip off quickly if need be.
     
  4. TSandM

    TSandM Missed and loved by many.

    # of Dives:
    Location: Woodinville, WA
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    The big markers, as has already been said, are better deployed from great depth, where air expansion helps you have a full marker on the surface. But even if it's full and taut, it won't stand up unless there is tension on it. I found out the hard way one day that, if you weight yourself perfectly neutral at your safety stop with 500 psi, you will be unable to put any downward tension on the line to make the bag stand. I added two pounds, and with that and, if necessary, a little downward finning, I can keep the marker standing. The taller the bag, the more tension you need on the line for it to remain vertical.
     
  5. fjpatrum

    fjpatrum Loggerhead Turtle

    # of Dives: 25 - 49
    Location: DC area
    2,759
    576
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    Thanks, everyone. g1138, I'm not sure what the difference is between your bag and mine, but even with light tension and half full, the marker simply wouldn't stand up, flat(ish) or not on the surface. I had to yank hard for it to stand up, for whatever reason.

    I think I might go ahead and just start deploying from depth, which will have several benefits as long as the surface current isn't ripping.
     
  6. g1138

    g1138 Marine Scientist

    # of Dives: 500 - 999
    Location: Charleston, SC
    2,914
    683
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    The trick might be putting all the tension in your arm. It took me a while to get. I OK my hand on top of the finger spool and just use arm tension to keep my SMB upright. I find that if you try to put your entire body into apply tension things get a little wacky. I really had to try this in 8ft at the pool to figure it out.

    I think it might be helpful to inflate your SMB halfway and then descend in the local pool so you can see what your SMB is doing.


    When I'm winding up, all the tension is in my off spool hand. I pinch the line with two fingers and pull down. My bolt snap is wrapped in my last three fingers of my off hand. Sometimes I'll press the boltsnap into the line with my thumb.
    I bring my spool up above my off hand and rotate my wrist, winding downward. (I hope that made sense)
     
    fjpatrum likes this.
  7. RTee

    RTee Divemaster

    # of Dives: 500 - 999
    Location: Ottawa, ON
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    As Lynne said, I tend to use Boyle's Law to assist me in filling my 6 footer and even my 3 footer. At 60 ft or so, I just need to do a third of the work. Once full, I just tend to remain slightly negative and lean on the spool in front of me using my hands. It is usually enough to tilt it up.
     
  8. Quero

    Quero Will be missed

    # of Dives: I just don't log dives
    Location: Phuket, Thailand
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    I have a five-footer that's easy to deploy from 15-20 feet (five-six meters)--it's skinny, so it makes "better" use of the air. Like others, I keep the tension through the arm and not the body. The first thought that came to mind when I read the post title was that maybe the air flowed out when the SMB reached the surface. It depends on the inflation mechanism, but for ones you just blow into an opening (rather than inflating with your LP hose), if you deploy and simply let the line play out freely as the SMB ascends, it sometimes rockets out of the water and loses a good portion of its air before it ends up lying flat on the surface. To rectify this, you need to apply tension to the line as the SMB rises so that when it reaches the surface the opening stays under water and all the air stays in it.
     
  9. t4e

    t4e Regular of the Pub

    # of Dives: 100 - 199
    Location: Burlington Ontario
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    based on the thread title this comes to mind :p
     
  10. Splitlip

    Splitlip Great White

    # of Dives: 500 - 999
    Location: Jupiter
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    As others have said, shoot from deeper depth. I use a manta reel which has never free spooled on me.

    I also concur with g1138; I'd rather have half of a 6ft x 7in marker over me than a full 1 meter by 2.5 in.
     

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