+ Reply to Thread
Page 1 of 5 1234 ... Last
  1. #1
    MembersZone Subscriber

    Join Date
    Oct 2002
    Posts
    36

    Default Which knot do you use?

    Which knot do you use when attaching a lowering line to a stokes basket for a vertical lower and why, the bowline or a figure 8?

  2. #2
    MembersZone Subscriber

    Join Date
    Jan 1999
    Location
    SCHAUMBURG, IL.
    Posts
    133

    Default

    Figure eight. The bowline was a good knot for braided rope but the kernmantle rope allows the bowline to slip. the figure eight will not slip

  3. #3
    Truckie
    SPFDRum's Avatar
    Join Date
    Mar 1999
    Location
    St Paul, MN
    Posts
    2,516

    Default

    Figure 8 with a safety is correct. With todays synthetic ropes and their core type construction, a bowline causes to much compression and extension at the radius' of the bends.
    My posts reflect my views and opinions, not the organization I work for or my IAFF local. Some of which they may not agree. I.A.C.O.J. member
    "I ask, Sir, what is the militia? It is the whole people. To disarm the people is the best and most effectual way to enslave them."
    George Mason
    Co-author of the Second Amendment
    during Virginia's Convention to Ratify the Constitution, 1788
    Elevator Rescue Information

  4. #4
    Forum Member

    Join Date
    Jan 2000
    Location
    Somewhere in the Backcountry...
    Posts
    176

    Default

    SPFDRum - What is your data source re: bowlines causing excessive compression/exstension at the radii? Generally, the larger the radius within the loops, the better the overall strength retention.

    A correctly tied and dressed bowline will not slip. It should be finished with a safety, but is a solid and safe knot. In fact, the bowline and figure-8 are widely used in the climbing world as the primary endline/tie-in knots where they are subjected to lead falls (e.g. possible high fall factors)regularly.

    In complex rigging situations the bowline is sometimes a good choice since it tends to be more compact and uses less rope. Variants of the bowline such as the "high strength bowline" and Yosemite tie-off variant are both good.

    Figure eights are good too and fine for the endline knot on a raising or lowering. It is probably more important to look at your bridle set-up to ensure that you don't have an arrangement that allows for cross or triaxial loading on a carabiner(s).

    That being said, my personal preference is the figure-8, but I can use a bowline as well. In some respects, interlocking bowlines are a good choice since you can use the tails as safety attachment points for a litter attendant and the subject.

    A correctly tied/dressed bowline or figure-8 will serve you well.

  5. #5
    Senior Member
    shammrock54's Avatar
    Join Date
    Jul 2001
    Posts
    445

    Default

    I was always trained to use a figure 8 w/ a safety.
    Member IACOJ & IACOJ EMS Bureau
    New England FOOL
    "LEATHER FOREVER"
    As always these are strictly my own opinions and views

  6. #6
    Truckie
    SPFDRum's Avatar
    Join Date
    Mar 1999
    Location
    St Paul, MN
    Posts
    2,516

    Default

    Mtn., I got it from a rope manufacture/vendor- which is like saying I got it from a car manufacture... - soon as I find my RIT training notes, I'll have the vendor listed there. It's more of a factor with static rope (which should be used for rescue) than dynamic, due to the construction of the kern.
    My posts reflect my views and opinions, not the organization I work for or my IAFF local. Some of which they may not agree. I.A.C.O.J. member
    "I ask, Sir, what is the militia? It is the whole people. To disarm the people is the best and most effectual way to enslave them."
    George Mason
    Co-author of the Second Amendment
    during Virginia's Convention to Ratify the Constitution, 1788
    Elevator Rescue Information

  7. #7
    Forum Member

    Join Date
    Jan 2000
    Location
    Somewhere in the Backcountry...
    Posts
    176

    Default

    SPFDRum - I am more curious than anything about the recommendation re: fig-8 vs. bowline. If a mfg'r is that "concerned" (i.e., has a potential life-safety issue) about excessive bend based on the radius of the inside of a knot there are many other concerns that should be considered - such as the bend created around the spine of a carabiner, etc. These radii are certainly similar to those created by most/many knots. Look at the bottom of a loaded loop next time you are off the deck with a 600 lb. load. You're going to have some pretty sharp bends.....

    Most static ropes have a core/kern that is composed of largely parallel running fibers w/some degree of "winding" to reduce/counter spin and provide some degree of dynamic performance. This also helps make them less "stretchy", unlike a true dynamic rope, which has a twisted core to provide a more spring-like (e.g., dynamic)characteristic. There are many factors that can come into play at this point including nylon "types" that are used (may yield different performance characteristics (e.g., modulus of elasticity, melting points, etc.), wear and strength loss characteristics (curvilinear vs. linear). There may be certain rope types that you don't want to use in a lowering/raising situation with a rescue load. Getting into the physics and material science of it will make your head spin.

    Anyway.... I am more interested than anything in hearing more about this since I haven't heard anything from some of my acquaintances, including several that are on the technical/engineering side of things w/equipment (including) rope manufacturers.
    Last edited by MtnRsq; 02-29-2004 at 01:09 AM.

  8. #8
    Forum Member

    Join Date
    Jul 2001
    Posts
    277

    Default

    Anytime I have used the bowline it has been interlocking bowlines with long tails. The rescuer and patient then can attach to a tail for a safety. If the rescuer is attached to the mainline tail and the mainline fails, he is still connected to the safety(belay) since the bowlines are interlocked. If you are attached to the tails, knot slippage is not a factor. On my team, however, the bowline has been removed from all evolutions so we use a twin butterfly.(mainline and safety tied parallel to form one "twin" knot).
    Sometimes, in order to make an operation idiot proof, you must remove the idiot!

  9. #9
    Forum Member

    Join Date
    Jan 2000
    Location
    Somewhere in the Backcountry...
    Posts
    176

    Default

    Resqtek - I'm curious as to why your team has removed the bowline from the menu in favor of the butterfly (I have a guess.....). The butterfly is a versatile knot, but not often used outside of mid-line applications.

  10. #10
    FIGJAM
    lutan1's Avatar
    Join Date
    Jan 2001
    Location
    I come from The Land Down Under!
    Posts
    1,833

    Default

    We always use the figure 8 family of knots.

    The bowline is too easy to get wrong for so many people.

    Furhter to that, I'm with othewrs- we've been told by rope manufacturers not to use the bowline on kernmantle rope as it slips, etc.
    Luke

  11. #11
    MembersZone Subscriber

    Join Date
    May 2000
    Location
    Wheaton IL
    Posts
    1,767

    Default

    The Bowline should not be used any longer for synthetic rope.
    It also weakens the rope more then the family of 8 knots.
    I think it was CMC that has tested the knots.

  12. #12
    MembersZone Subscriber

    Join Date
    Jan 2004
    Location
    Santa Rosa County, Florida
    Posts
    160

    Default

    We use the Figure 8 on a bight, and also have started using the figure of 9 for other lifting or anchoring.

  13. #13
    MembersZone Subscriber

    Join Date
    Oct 2002
    Location
    Pennsdale, PA
    Posts
    47

    Default

    My experience with the Bowline in synthetic ropes is that they must be safetied or, as they are loaded and unloaded in a cyclic manner, the tail can work its way backward, untying the knot. This is, I feel, related to the smoothness of modern nylon ropes. When the bowline is used in rough ropes such as manila, the strands "bite" into each other, increasing the friction within the knot and keeping it tight, even when unloaded. The knot itself is not as strong in pull testing as the Figure 8 and Figure 9, but I have seen no published scientific studies that say the bowline must be abandoned. The bowline is referred to in many of the current texts on rope work both here in the US and in Great Britain. Interlocking longtailed bowlines are my preferred attachment method.

  14. #14
    Forum Member

    Join Date
    Jul 2001
    Posts
    277

    Default

    MtnRsq, they removed the bowline from the menu because they found alot of people were tying it wrong and the figure 8 family of knots can do almost everything in place of the bowline. I beleive the strength loss in the bowline was a factor as well. I personally like the bowline. It is quicker for tying around an object and uses less rope than the fiq 8 follow through. It is a safe knot when tied in the Yosemite configuration and when using it for a litter attachment where a tail is needed, it keeps the rigging tight as you can eliminate a carabiner by tying to the ring on the bridle. I don't personally feel the strength loss is a big deal when you are working with a 15:1 safety factor.
    Sometimes, in order to make an operation idiot proof, you must remove the idiot!

  15. #15
    Forum Member

    Join Date
    May 2000
    Location
    Ga. Power Co./ Juliette Ga
    Posts
    437

    Default

    This may sound stupid, but what is a "Figure 9" knot?

  16. #16
    Forum Member

    Join Date
    Jul 2001
    Posts
    277

    Default

    A figure 9 is very similar to a figure 8 on a bight except you make another half turn arond the standing part before passing the bight through the hole. It is supposed to be one of the strongest knots. I don't see the value in teaching another knot for a couple percent difference in strength loss. If you are that close to failure, the problem doesn't lie with the knot you are using. If I am concerned about strength loss due to a knot I will use a soft interface conection. This is acheived by tying a 3 wrap prussik onto the standing part of the rope above the figure 8. Create about 6-8 inches of slack between the prussik and the knot and attach your carabiner to both the prussik and the figure 8. This way, the prussik takes the load and the figure 8 does not. If there is any sever loading, the prussik will slip on the rope at about 1800-2400 lbs force until the prussik and the figure 8 are sharing the load. This will give you almost 100% rope strength. This is a common technique for highline rigging where high forces are expected but it can be used for any rigging.
    Sometimes, in order to make an operation idiot proof, you must remove the idiot!

  17. #17
    MembersZone Subscriber

    Join Date
    Oct 2002
    Location
    Pennsdale, PA
    Posts
    47

    Default

    The Figure 9 is a Figure 8 with one more wrap around the standing part of the line. It is stronger than the Figure 8 in pull testing and is easier to untie after loading. It is more bulky than the Fig 8 due to the extra wrap. Follow this link for a drawing: http://www.cavepage.magna.com.au/cave/knot.html#fig9[/URL]

  18. #18
    Forum Member

    Join Date
    Jan 2000
    Location
    Somewhere in the Backcountry...
    Posts
    176

    Default

    This has been a good discussion thread. I would comment on the notion that the bowline has some significant safety flaw. Is this destined to become the next rope rescue "truism"?

    Like all rescue tools, knots have performance characteristics and pros/cons that we must understand in order to use them appropriately.

    I've noted in other threads, particularly re: technical rescue that the focus is often on equipment, equipment, equipment and getting the latest/greatest when, frankly, people would be better off learning the hows/whys from competent instructors so that they can make informed decisions to accomplish the goal.

    It frankly scares the hell out of me if someone can't competently tie a range of common knots, tell if they are correct or not, etc. What else can't they do? Is there some other factor that is being missed? If the rescue is not "textbook" and folks need to think out of the box we have potential disaster.

    Enough soap box..... By the way, I like the figure-9. Waaaay easier to untie after loading.
    Last edited by MtnRsq; 03-03-2004 at 12:16 AM.

  19. #19
    Junior Member

    Join Date
    Aug 2000
    Posts
    24

    Default

    Hello,
    I like the use of the butterfly knot and tri-link to rig a basket for horizontal lowering. It was stated earlier that it "is mostly used for mid-line attachment". ~~~~YES~~~ That is exactly what the litter attachment from mainline and safety is - midline! (The tails are used for safety attachments for the rescuer and patient.) And, the tri-link eliminates any tri-loading. TIP - Use the largest, strongest tri-link you can find! Not many equipment suppliers offer the LARGE tri-link. I think they like the higher profit margin carabiner!

    I also like the figure 9 knot!

    MtnRsq,

    I like your soap box, keep screaming the message to all that will listen!!!

    Thanks...
    *~~~John J. Troyer~~~*
    -Sedgwick County FD Wichita, KS
    Lieutenant - Tech Rescue Station #37B
    -Hutchinson Community College
    Instructor - OSHA, Fire, Rescue
    -Norwich Fire Department
    Volunteer Firefighter

    Stay safe and remember, Gravity never sleeps!

  20. #20
    MembersZone Subscriber

    Join Date
    Oct 2002
    Location
    Pennsdale, PA
    Posts
    47

    Default

    There is no doubt there are a number of effective methods of interfacing the basket stretcher rigging with the main line system. Teams should look at various methods and decide, based on their specific needs and experiences, which will work best for them. The key is that, rather than relying on some dogmatic statement made by a rescue "guru" somewhere, the team must decide based on expereince and needs what works best. There is finally some reproducible scientific research being done to give us some empirical guidance on what may be the safest pracitces. We, as rope rescue practitioners, should be encouraging additional research and reading the results of the research that has been done. A lot of very pertinent information is presented annually at the International Technical Rescue Symposium. The proceedings are available from CMC rescue at a very reasonable cost. We can read the results of studies done by industry leaders about the strength of various webbing anchor configurations, what happens when carabiners are crossloaded, the effects of permanent markers on rope and webbing strength, and many more topics. Then, based on this knowledge, we can make more educated decisions on what our own best practices should be.

  21. #21
    Forum Member
    firespec35's Avatar
    Join Date
    Nov 2002
    Location
    Milford MI USA
    Posts
    213

    Default

    When I was in the academy in '98 (Yes, I know I'm still a pup, I bow to the mighty veterans knowledge) They told us that the bowline was not safe on kernmantle rope and the "8" series of knots were much safer. I haven't heard anything to the contrary since.

  22. #22
    Forum Member

    Join Date
    Jan 2000
    Location
    Somewhere in the Backcountry...
    Posts
    176

    Default

    When I was in the academy in '98 <snip> They told us that the bowline was not safe on kernmantle rope and the "8" series of knots were much safer. I haven't heard anything to the contrary since.
    Sigh - there it is - the gospel taught to many.

  23. #23
    Junior Member

    Join Date
    Aug 2000
    Posts
    24

    Default

    With the off chance of sounding argumentative...

    RemptyP,

    He did ask "Which knot do you use when attaching a lowering line to a stokes basket for a vertical lower and why, the bowline or a figure 8?" We were just giving him options to try and see which one they like. No one is trying to be a "guru" here. We are giving him the options he asked for.
    *~~~John J. Troyer~~~*
    -Sedgwick County FD Wichita, KS
    Lieutenant - Tech Rescue Station #37B
    -Hutchinson Community College
    Instructor - OSHA, Fire, Rescue
    -Norwich Fire Department
    Volunteer Firefighter

    Stay safe and remember, Gravity never sleeps!

  24. #24
    MembersZone Subscriber

    Join Date
    Oct 2002
    Location
    Pennsdale, PA
    Posts
    47

    Default

    My "guru" comment was in response to the several postings of "I was taught" that this or that is not to be used. What evidence did the instructor cite to the students that the bowline is unsafe in kernmantle rope? What studies were done? Why are we accepting of these blanket statements by instructors without hard evidence to back up their statements? I infer, from these postings, that we have a group of young rescuers who have accepted as gospel whatever their instructor fed them in their first course. When I first started in rescue we routinely used mechanical camming devices as belays. Then some people did some reproducible testing and discovered that those mechanical devices may not be as safe as other methods in instances where the belay could be shock loaded, which led to changes in the way many people belay. Rope rescue as we know it today is a very young discipline and very little scientific study has been done regarding our methods. That is something something that those of us in the trenches should be pushing for - quantitative information on what best practices are.

  25. #25
    Forum Member

    Join Date
    Jul 2001
    Posts
    277

    Default

    Rigging for Rescue from Invermere, B.C. and Ouray, Colorado(sp?) are an excellent source of information for testing done on rescue techniques. They did a demonstration at the technical rescue symposium a couple years ago showing the dangers of attaching the belay to the dorsal d-ring. There is also some great info on the unnecessary danger presented by the use of shock absorbers in rescue systems. I am taking one of their courses this year. They encourage you to question everything and make them prove it to you. You can also bring some gear to do destructive testing at their facility.
    Sometimes, in order to make an operation idiot proof, you must remove the idiot!

+ Reply to Thread
Page 1 of 5 1234 ... Last

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts

Log in

Click here to log in or register