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When to blow your bag?

Discussion in 'Technical Diving' started by dave22387, Mar 26, 2014.

  1. Diver0001

    Diver0001 Instructor, Scuba

    0
    63
    Yes, well clearly if you're diving from a boat in heavy current and you're not making use of any kind of up-line then you need to get your marker on the surface. There's more involved here than just when to launch the blob, though. On our local wrecks if you didn't use an up-line you'd be lucky if you didn't wash ashore in England because of the currents. With, say, 6-8 divers in the water if everyone just went drifting off the wreck, blob or no blob, then we'd have lost-divers every weekend.

    That triggered me because the agreement we have with the skippers here is that everyone uses an up-line that's anchored to the wreck and if a blob gets spotted then it means you're unable to use the up-line for some reason and need to make a non-standard ascent. The point being that if the OP is diving from a boat that the crew should know how he intends to use his blob too.

    Just a thought.

    R..
     
    TTPaws and waterpirate like this.
  2. Cave Diver

    Cave Diver Divemaster

    17,866
    2,523
    +1 to this. Been there, done that, stressed out the crew looking for us.
     
  3. ajduplessis

    ajduplessis Solo Diver

    # of Dives: I'm a Fish!
    Location: dry land :-(
    3,256
    836
    I always shoot from the bottom and always as a group together. Current as already mentioned has the tendency to drift you wherever it goes. Slight delays in bag launches also can separate divers quickly. Separation within a group causes severe headaches for the team(s) topside that needs manage the situation and available resources. When, where and how you shoot bags is a topic within a dive briefing and must be carefully considered.

    On deep dives I have 2 primary DM reels and SMB's (redundancy) both with 500ft of high viz Dacron lines. I have seen jammed reels and SMB failures and will not dive without a backup.
     
    Last edited: Mar 27, 2014
    Nuribromanski likes this.
  4. LiteHedded

    LiteHedded Contributor

    4,075
    922
    top notch crew and we discussed our ascent with them on the surface.
    had to cut the ball off the wreck...
     
  5. Centrals

    Centrals Barangay Pasaway

    # of Dives:
    Location: Hong Kong
    9,656
    3,528
    1. Never shoot a bag on wreck dive unless failing to return to the shot line. Very naughty.
    2. If it is a wall dive then I will only shoot the bag just before leaving my final deco stop at 6m.
    3. If it is a blue water ascent then I will shoot the bag at 21m where I always allocated extra couple of minutes on the dive plan for changing gas and deploying smb. The boatman also know when to expect the smb popping up.
    4. In water up-date!! eg. blown away.
    5. Used to use reel but only with spool nowadays. Three spools and 2 smb are usually carried. In really ow wreck dive then I will carry an extra yellow colour smb.
     
  6. Nasser

    Nasser ScubaBoard Supporter ScubaBoard Supporter

    544
    233
    Diving in warm clear water here to 60m max and currents generally mild, so I shoot the bag at first stop longer than a minute... on average around 12m or 9m. I use a spool.

    Probably what can be inferred here is that it depends on your environment, diving conditions, type of dive and what is agreed on with dive team and crew.
     
    Peter69_56 likes this.
  7. Peter69_56

    Peter69_56 Divemaster

    # of Dives: 500 - 999
    Location: Australia
    1,538
    632
    Agree totally, one size does not fit all.

    For shooting 30m or less I use a spool. I carry 2 - 50m spools and 2 SMB. For anything greater than 30m I will carry an 80m reel as well. However the initial plan always is to go back via the upline. Keeps you attached to the boat and keeps the group together and no need to shoot a bag at all.

    Have done drift dives where the group is strung out over 2 km which makes it hard for the crew to keep track of everyone, and a recipe for disaster.

    Like this too, and I have my second SMB yellow. Local dive boat tech rule is, if a yellow SMB goes up, someone is in trouble and requires assistance. SMB will have a slate on it
     
  8. gekodivebali

    gekodivebali Tech Instructor

    # of Dives: I'm a Fish!
    Location: Padang Bai
    874
    430
    Sometimes I don't!
    Shore deco dives in Tulamben come to mind.
    The rest of the time the amount of current and what direction (if only one) it blows will dictate depth.
    It has happened that I would not deploy til 5m in strong currents since I had such a fun time holding on a rock at 6m ;-)
     
  9. syntaxerrorsix

    syntaxerrorsix ScubaBoard Supporter ScubaBoard Supporter

    1,007
    230
    Dives on the East coast of Florida are going to entail current. We tend to hot drop the wrecks and drift the deco so bags are shot at the end of bottom time before we get off the wreck so the boat can follow. As previously mentioned scope in these conditions require more line than any spool I know of. I'd love to watch someone with a spool shoot a bag from ~200' with a 5-7 knot current.
     

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