1. #1
    Senior Member

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    From North Pole, AK to Hell, OK
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    Default Stokes Basket rigging/strength of directional 8's

    Got a question for ya:

    How do YOU clip in to a Stokes as a victim attendant?
    Could you tie a Directional 8 with both the main line and the safety, clip the stokes in each knot's loops, and then come down with 4' or so and then clip your harness into both via Fig8 on a bight (& prussik for adjusting) WITHOUT losing much system strength? How much stronger is a full 8 as opposed to a directional?

    Why would you use a double line lowering system on a Stokes? Not a Main and a Safety, but two Main lines to lower. Seems to me it'd be hard to maintain the proper angle for the pt.

    In unrelated news, why the hell are we still teaching the bowline?

    'PRECIATE IT!!!!!!!!


    P.S. - I found the knot strength thread further down in Specialized Rescue, per CMC Rope Rescue Manual, a Fig 8 on a bight is 4% stronger than an "Inline 8", which I am assuming is what I know as a Directional 8. Which brings me to another question. If a Fig 8 on a bight decreases strength by 19%, how come a Fig 8 follow-through weakens it 21% (I may have my numbers backwards, but you get the idea) if they are the same knot, just tied differently? Hmmmm....
    Last edited by MrFreeze; 03-02-2002 at 03:20 PM.
    ...if you put the handline in the right spot, you won't have to jump out the window...
    -Andy "Nozzles", SQ18, 9-11-01

  2. #2
    Senior Member

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    Default

    Just bringin' it back to the front...
    ...if you put the handline in the right spot, you won't have to jump out the window...
    -Andy "Nozzles", SQ18, 9-11-01

  3. #3
    MembersZone Subscriber

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    Default

    We have everything attached to the proof ring that your main line is attached to. Sorry don't have any pictures so I'll try too describe it.

    The main lowering line is attached to the proof ring with a follow through fig 8. (For added security we have used a butterfly with the end attached to the head of the stokes with an 8. I personally don't see a need because that ring is usually twice as strong, or more, as the rope, so I'm confident that it isn't going to fail.) The stokes is secured by the 4 adjustable straps that came with the stokes.

    We use a smaller line for the attendant. The line is about 10' long and goes from the ring to the attachment point on the rescuer's lower back. The front attachment is secured to the rope using a handled assender or gibbs or accessory cord. a second assender with foot loop to use as a step. You can move up or down this line to do whatever is needed.

    Our safety is attached to the head of the stokes and then the attendant. Once over the side and on line it works well for us.


    PS we stopped using an in-line 8 because of the reported strength loss over a butterfly. Also the butterfly can be used in a three way pull vs the 8 that is designed for only a two way pull.
    Last edited by ADSNWFLD; 03-03-2002 at 04:13 PM.

  4. #4
    MEDIC O372
    Firehouse.com Guest

    Default

    We use a Long Tail Bowline on the end of the Rescue line and the Belay line...We attach the litter tendant to the Long Tails of the Bowline. This is the only application that we would use a Bowline in Rescue. It is a very safe and easy system to use.

    A long Tail Bowline is a Bowline with about an 8 to 10 foot tail. We tie the Bowlines directly to the Stoke bridle...no hardware is used. We attach the tender to the tail of the Rescue line with a prussic so that he can move up and down the line.

    Regarding the question of using two main lines instead of a rescue line and a belay line (1 line system vs 2 line system). There are a couple resons why you may want to do this. One is if you are using two litter attendants and you have one person in the stokes...that will then add up to three people supported by the rescue line. In order to keep the basket level you need good communications but it is not all that difficult to do. Sometimes it is actually easier to use the two main line system in rough terrain type rescues off cliffs and such.

    It is good to know how and when to use the different types of systems. Most times though...we would use the 1 main line and 1 Belay line system (one line system).

    Take care and be safe but most of all have fun,
    Medic 0372
    Last edited by MEDIC O372; 03-04-2002 at 09:42 AM.

  5. #5
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    Default Litter Rigging

    Our rigging varies according to raise/lowering type - vertical or horizontal.

    Verticals are used for lower angle/scree type situations. Horizontals are used for vertical/high angle situations.

    We use a double line (2 "mains") on both. For a horizontal raise (vertical environment) we attach to the main lines via 8s on bights and 'biner into the bridle/spider attached to the litter (positioned so the patient rides slightly head up). The attendant (usually a single person) has a safety line connected into the mains and a "positioning" line also attached. The attendant may move up/down this line via an ascender (handled, Jumar-type) as necessary & may utilize a small M:A/jigger system if nec. to move from vertical to horizontal, etc.

    For verticals (lower angle) we usually use two attendants (one on each side) attached in a similar manner. The main lines are 'binered to two separate/short loops of rope that are attached to the litter @ the head. Since the attendants are "walking" the litter up/down their positioning lines are "wound" around the litter rail which allows them to carry much of the weight in their hips/legs.

    Long tail bowline set-ups also work very well.

    The issue of knot strength is usually not an issue. There are many other factors in most situations (for instance - anchors).

    Note - we are operating almost exclusively in rough terrain/cliff environments often several miles from road access. Raises/Lowers may be 100's of feet. We strongly prefer two line systems w/both lines operating as mains. Issues w/slack are nil, we can spread people out over two lines to give pulling umph (and avoid any risk of "over pulling") and make use of sometimes very limited working spaces.

  6. #6
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    Lightbulb

    When we do the rigging on a vertical, we often use the technique you described with the directional 8 at the top hooked to the basket and the 8 on a bight on the end about 4' down. This works very well in giving the rescuer 2 points of contact as well.

    As far as the double line on the lower, we use a 2 line system for everything. Both lines have to be belayed at the same time. The "main" line is usually ran through a brake bar rack, with the "secondary" or backup line, ran through a rescue 8, unless it is a long lower, then we use 2 racks. This still gives the basket a 2 point system for safety.

    As far as the question about the bowline, sometimes it works better to tie a bowline at the foot of a basket for a tag line and it is quicker than tying a follow through 8. Where strenghts are concerned, the follow thru and the 8 on a bight are the same knot and should have the same strength. The "in line 8" is an 8 on a bight tied somewhere in the middle of the rope, not on the end. The directional 8 will actually give you about 3%-4% more strenght in that situation due to the stress on the ropes.

    For the guys that are using a butterfly in the rigging system for a basket, that knot will weaken the system by 37%, as opposed to an 8 on a bight only 25%. Butterfly's work well for anchors, but I don't like using them on a basket. Also, they are harder for people to learn to tie.

    One thing to remember about all your rigging. K-I-S-S...
    Keep It Simple, Stupid.

    The simpler the rigging, the less chance of messing it up. Always use the same setup to rig your baskets and practice often. This way, all your squad will be familiar with the system and know what to do if they end up on the basket.

    If you are interested, I have learned a different method of rigging a vertical rig on a basket using a single 30'- 1/2" rope. It works really well and came from a squad that does about 50 technical Mtn. Rescues each year. E-mail me if you are interested. I have some pictures and can easily describe it for you.

    Train hard and Be Safe!
    Tell me, I will forget. Show me, I will remember. Involve me, I will understand.

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