"limp" SMB

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

  1. fjpatrum

    fjpatrum Surface Interval Member

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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 Tech Diver

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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 NAUI Instructor

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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.

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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 Surface Interval Member

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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 NAUI Instructor

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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)
     
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  7. RTee

    RTee Divemaster

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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

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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

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    based on the thread title this comes to mind :p
     
  10. Splitlip

    Splitlip Surface Interval Member

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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.
     
  11. GrumpyOldGuy

    GrumpyOldGuy Great White

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    Since no one else will say it I will, maybe the limp SMB is a reflection of your manhood.;)

    Seriously, if you deploy from depth and let some pressure build up it will tend to stand erect. :D

    You need enough pressure to keep it standing at attention and the OPV will protect you (at least for up to 4 hours).

    I think I said enough.
     
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  12. dumpsterDiver

    dumpsterDiver Scuba Instructor

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    Also something to consider... If it is windy and rough the SMB will get pushed over hard. The stronger the wind, the more tension you have to put on the line (i.e., negative weight) to keep it close to vertical. You may need considerable negative bouyancy at depth to keep a large SMB in a vertical position when it is rough. The taller the float, the more wind resistance and them more it gets blown over.

    There is a point of diminshing return of large and larger markers..
     
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  13. RonFrank

    RonFrank Orca

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    I have a few SMB's. I carry a smaller one when vacationing maybe 5'. The big ones are nice but I have to attempt to travel light which is a joke for a diver. But generally the seas are mild and I do not have to unroll my SMB.

    Having them stand strait up while you are underwater is less important then when your at the surface. That's when you want to be picked up. The seas are generally less than 4'. If they waves are 6' or greater the boat is still going to be looking for you, so a SMB is what you want. If your with your buddy you should have two! The boat is not going to leave divers behind.

    If your leading a drift dive you will be dragging a float usually provided by the boat. In that case remember the golden rule. He who has the gold makes.... umm wrong rule. The person towing the float is never lost. IOW they are the leader even if they loose everyone! Stay with the float, that is the rule. You can yell at them later for not being on the reef. :D

    On drift dives the boat can generally do a good job of following divers. In Coz they just look down! In FL they often follow the bubbles. But generally the current is running at a similar speed and direction. Boat Captains are rather used to finding their divers.

    Good Diving
     
  14. Splitlip

    Splitlip Surface Interval Member

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    Edit: my reply was meant for DD, not Ron.

    I carry a couple extra pounds for this reason. And I am not afraid of hanging in a vertical position if it means keeping the marker upright. A video of me was posted by someone on a couple forums and the comments were essentially "OMG. Who is that person? He is almost vertical in the water!". I'd rather have a good marker above me than to look pretty by someone else's standards.
     
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  15. Dr Dog

    Dr Dog DIR Practitioner

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    Tie a knot in your line at about 17 to 18 feet also. This will help keep you at your safety stop and not have you staring at your depth gauge for 3 minutes
     
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  16. Quero

    Quero Will be missed

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    The knot thing only works if there's no surface current. If there is a current, you can need significantly more linear feet/meters of line for any given depth.

    I prefer to be vertical on the safety stop in order to put negative tension on the line. A visible SMB while I'm still under water has a high priority for me for reasons of boat traffic.

    That's why I like the 5 ft/5.5 inch one I routinely use. It takes 40% less air to fill it than it would take to fill a 7" wide one, and it's not that much smaller.
     
    Last edited: May 10, 2012
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  17. awap

    awap Giant Squid

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    I like to launch from a 30' stop. If it does not stand proud it should still work fine to keep boats from running over you at your RS and as you surface. Then you can top it off and wave it around to attract more distant boats.
     
  18. Splitlip

    Splitlip Surface Interval Member

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    Further, I scan 360 during my accent. I've been hit by a boat, and I hate that. It is so much easier to to look around at the surface while vertical.
     
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  19. Quero

    Quero Will be missed

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    Never been hit by a boat, but we did have a death here last year when a girl surfaced into a moving prop. The only time I don't deploy my SMB is when my boat is tied up and I'm doing an out-and-back dive.
     
  20. Centrals

    Centrals Barangay Pasaway

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    I use a Buddy(1.5m) smb with OPV. Always ascend horizontally unitl the last metre. The boatmen never complained of NOT spoting the smb from distance. It takes time and practice to deploy a smb "properly erected" from 6m and I use my primary 2nd stage to inflate it.
     

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