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Sunday
Mar012015

10 Golden Rules of Knot Tying

1)A knot, bend or hitch is either right or totally wrong; one mistaken tuck or turn results in a different knot – or no knot at all.

2) Use the simplest Knot applicable to the job at hand.

3) Simplicity may be had only at the expense of friction.

4) Strength and security are distinct and discrete characteristics in a knot.

5) Knots weaken rope/line.

6) A knot is only as good as the line in which it is tied.

7) All knots must be systematically worked snug, a bit at a time, prior to tightening them (dressing the knot).

8) A poorly tied knot is less effective than the same knot properly (dressed) and tightened.

9) Use fingers to tie small cordage, but hands and arms to manipulate large ropes (line larger than 10mm in diameter) and cables.

10) Knots that can be untied in the bight may be tied in the bight.

These rules are dedicated to the principle that sooner or later you will be handed a rope’s end or (line) and be expected to do something useful with it. Quote (Geoffrey Budworth). For “practical” use this link to practice your skills.

Before we take a close look at each of these rules and their implications of design, be sure to remember you can visit my entire video collection of knot tying practical’s at this (link.) Or view my other rope article in the archives at www.hazmatmike.com entitled “New Beginnings; the Knot-of-the-Day.” Be sure to check this out, as it gives you a template for setting up an Instructional Base for your Response group.

1)    Each particular “knot” is unique to its construction. Any deviation from the method of construction resulting in the knot being improperly tied may very well result in the failure of the knot under load. When a life is suspended by these knots death can result. When equipment is suspended, serious injury to those below as well as destruction to your equipment can result. This is exactly why; the knot tier “should always construct or (build) the knot the way you are looking at it.” I especially took great care to demonstrate this in the videos. By “building” your knots in this manner, you eliminate the possibility of an improperly tied knot. Trick wrist flips and arm turns to master a knot leave the door open for mistakes. When developing “your” training, always start from this position. Do NOT allow any deviations by Team members as to how “they learned.” Knot construction in this manner also allows the Trainer to inspect the student’s knot tying ability for correctness and safety.

2)    There are many exotic knots that will do the same job as simply constructed ones. Avoid demonstrating your “knot crafting prowess” by avocation of an exotic knot over a simple one. Ultimately; safety and success are your goals NOT to impress your fellow Team mates. By using simpler knots you accomplish two goals; 1) proper construction before a life load is placed on the line, and 2) simpler knots are easily “untied” after a load is removed from the line. Always untie knots after use; this reduces wear in the line. Also, remember rule 1). During long operations, when exhaustion sets in, complex knot construction is more likely to slip through inspection before a life/equipment load is attached.

3)    The only exception to rule #2 is in the case of “friction.” Friction is a unique principle that must be fully understood before knot tying begins. “Friction” is the force that resists the motion of one surface relative to another with which it is in contact. No matter how smooth your “lines” appear to be to the naked eye, with a microscopic view, you can observe many humps, valleys, and crests. This means the actual area of contact is very small while subjected to high pressure “welding” of the frictional line surfaces. It should also be known that during movement, these welds are broken and remade frequently. This is known as “rolling friction” the long term result we refer to as “wear.” These factors demonstrate the critical importance of rules #1 and #2. So, as long as simplicity does not compromise the safety of “friction” for the load being considered your knot choice is wise. These principles are critical to understand when choosing your SOP operational knots for your response group.

4)    It is critical to understand the difference between the concepts of strength and security in knot crafting. “Strength” refers to the knots reduction impact on the lines ability to carry a measured load. While “security” refers to HOW easily the knot can become undone (or untied) during the overall use of the system you have built. Such as, the working conditions of chaff, whether or not the lines in the system are wet (water or chemicals) and the angle of pull when measuring Force on the line specific to the dynamics of the system constructed. It is important to take in affect the concept of “directionals.” When pulleys are inserted into a system, remember there is equal and additional force being exerted on the line in both directions of pull. This multiplies the force on the line, thus lowering the total line safety margin of your system.

5)    Because of the physics of knot crafting, the curvatures of knot-building within a line weaken your cordage. In my second book “Practical Confined Space”, there is a detailed line chart demonstrating the load reductions of various knots used in line. These values must be calculated into your 15 to 1 Rescue Safety margin for determining the maximum safe load you can suspend.

6)    Since this phenomenon occurs, the quality, type and style of line being used must match the situation. Also, if the line is to be shock loaded, the benefits of dynamic line should be considered. Static line may not be the answer for every situational use.

7)    In order to minimize this phenomenon of load reduction through knot crafting all knots must be properly “dressed” BEFORE they are snugged-up for use within your rescue system.

8)    Quick or poorly “dressed” knots increase load loss, thereby becoming less effective. If a knot is rated at a load loss of 21% of the lines total load rating, a poorly dressed knot of the same type can exceed 30% of this rating. When calculating safety margins, an additional 9% could very well violate your safety ratio (15 to 1), thus endangering personnel, equipment, or victims. This practice could increase “line snap” when loaded.

9)    Matching your hand/arm motion to the cordage size is helpful when tying operations involving different size line. This generic format for “workability” should be followed; hands for lines up to 12mm (1/2”) and arms for larger cordage. This will enhance the ease of knot-crafting and reduce responder fatigue.

10)           Lastly; any knot that can be tied “in-a-bight” can inversely be untied in that bight. Your group will need one more thing to get you started. A good knot crafting training class geared to your operation AND a text-book of knots in your SOP for reference. This is always a benefit and gives your group a solid template to begin from and to conduct “refresher” Training.

 

                       Haz Mat Mike

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